absence.rb

# frozen_string_literal: true

module ActiveRecord
  module Validations
    class AbsenceValidator < ActiveModel::Validations::AbsenceValidator # :nodoc:
      def validate_each(record, attribute, association_or_value)
        if record.class._reflect_on_association(attribute)
          association_or_value = Array.wrap(association_or_value).reject(&:marked_for_destruction?)
        end
        super
      end
    end

    module ClassMethods
      # Validates that the specified attributes are not present (as defined by
      # Object#present?). If the attribute is an association, the associated object
      # is considered absent if it was marked for destruction.
      #
      # See ActiveModel::Validations::HelperMethods.validates_absence_of for more information.
      def validates_absence_of(*attr_names)
        validates_with AbsenceValidator, _merge_attributes(attr_names)
      end
    end
  end
end

abstract_adapter.rb

# frozen_string_literal: true

require "set"
require "active_record/connection_adapters/sql_type_metadata"
require "active_record/connection_adapters/abstract/schema_dumper"
require "active_record/connection_adapters/abstract/schema_creation"
require "active_support/concurrency/load_interlock_aware_monitor"
require "arel/collectors/bind"
require "arel/collectors/composite"
require "arel/collectors/sql_string"
require "arel/collectors/substitute_binds"

module ActiveRecord
  module ConnectionAdapters # :nodoc:
    # Active Record supports multiple database systems. AbstractAdapter and
    # related classes form the abstraction layer which makes this possible.
    # An AbstractAdapter represents a connection to a database, and provides an
    # abstract interface for database-specific functionality such as establishing
    # a connection, escaping values, building the right SQL fragments for +:offset+
    # and +:limit+ options, etc.
    #
    # All the concrete database adapters follow the interface laid down in this class.
    # {ActiveRecord::Base.connection}[rdoc-ref:ConnectionHandling#connection] returns an AbstractAdapter object, which
    # you can use.
    #
    # Most of the methods in the adapter are useful during migrations. Most
    # notably, the instance methods provided by SchemaStatements are very useful.
    class AbstractAdapter
      ADAPTER_NAME = "Abstract"
      include ActiveSupport::Callbacks
      define_callbacks :checkout, :checkin

      include Quoting, DatabaseStatements, SchemaStatements
      include DatabaseLimits
      include QueryCache
      include Savepoints

      SIMPLE_INT = /\A\d+\z/
      COMMENT_REGEX = %r{(?:--.*\n)*|/\*(?:[^*]|\*[^/])*\*/}m

      attr_accessor :pool
      attr_reader :visitor, :owner, :logger, :lock
      alias :in_use? :owner

      set_callback :checkin, :after, :enable_lazy_transactions!

      def self.type_cast_config_to_integer(config)
        if config.is_a?(Integer)
          config
        elsif SIMPLE_INT.match?(config)
          config.to_i
        else
          config
        end
      end

      def self.type_cast_config_to_boolean(config)
        if config == "false"
          false
        else
          config
        end
      end

      def self.validate_default_timezone(config)
        case config
        when nil
        when "utc", "local"
          config.to_sym
        else
          raise ArgumentError, "default_timezone must be either 'utc' or 'local'"
        end
      end

      DEFAULT_READ_QUERY = [:begin, :commit, :explain, :release, :rollback, :savepoint, :select, :with] # :nodoc:
      private_constant :DEFAULT_READ_QUERY

      def self.build_read_query_regexp(*parts) # :nodoc:
        parts += DEFAULT_READ_QUERY
        parts = parts.map { |part| /#{part}/i }
        /\A(?:[(\s]|#{COMMENT_REGEX})*#{Regexp.union(*parts)}/
      end

      def self.quoted_column_names # :nodoc:
        @quoted_column_names ||= {}
      end

      def self.quoted_table_names # :nodoc:
        @quoted_table_names ||= {}
      end

      def initialize(connection, logger = nil, config = {}) # :nodoc:
        super()

        @raw_connection      = connection
        @owner               = nil
        @instrumenter        = ActiveSupport::Notifications.instrumenter
        @logger              = logger
        @config              = config
        @pool                = ActiveRecord::ConnectionAdapters::NullPool.new
        @idle_since          = Process.clock_gettime(Process::CLOCK_MONOTONIC)
        @visitor = arel_visitor
        @statements = build_statement_pool
        @lock = ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new

        @prepared_statements = self.class.type_cast_config_to_boolean(
          config.fetch(:prepared_statements, true)
        )

        @advisory_locks_enabled = self.class.type_cast_config_to_boolean(
          config.fetch(:advisory_locks, true)
        )

        @default_timezone = self.class.validate_default_timezone(config[:default_timezone])

        @raw_connection_dirty = false

        configure_connection
      end

      EXCEPTION_NEVER = { Exception => :never }.freeze # :nodoc:
      EXCEPTION_IMMEDIATE = { Exception => :immediate }.freeze # :nodoc:
      private_constant :EXCEPTION_NEVER, :EXCEPTION_IMMEDIATE
      def with_instrumenter(instrumenter, &block) # :nodoc:
        Thread.handle_interrupt(EXCEPTION_NEVER) do
          previous_instrumenter = @instrumenter
          @instrumenter = instrumenter
          Thread.handle_interrupt(EXCEPTION_IMMEDIATE, &block)
        ensure
          @instrumenter = previous_instrumenter
        end
      end

      def check_if_write_query(sql) # :nodoc:
        if preventing_writes? && write_query?(sql)
          raise ActiveRecord::ReadOnlyError, "Write query attempted while in readonly mode: #{sql}"
        end
      end

      def replica?
        @config[:replica] || false
      end

      def use_metadata_table?
        @config.fetch(:use_metadata_table, true)
      end

      def default_timezone
        @default_timezone || ActiveRecord.default_timezone
      end

      # Determines whether writes are currently being prevented.
      #
      # Returns true if the connection is a replica.
      #
      # If the application is using legacy handling, returns
      # true if +connection_handler.prevent_writes+ is set.
      #
      # If the application is using the new connection handling
      # will return true based on +current_preventing_writes+.
      def preventing_writes?
        return true if replica?
        return ActiveRecord::Base.connection_handler.prevent_writes if ActiveRecord.legacy_connection_handling
        return false if connection_class.nil?

        connection_class.current_preventing_writes
      end

      def migrations_paths # :nodoc:
        @config[:migrations_paths] || Migrator.migrations_paths
      end

      def migration_context # :nodoc:
        MigrationContext.new(migrations_paths, schema_migration)
      end

      def schema_migration # :nodoc:
        @schema_migration ||= begin
                                conn = self
                                spec_name = conn.pool.pool_config.connection_specification_name

                                return ActiveRecord::SchemaMigration if spec_name == "ActiveRecord::Base"

                                schema_migration_name = "#{spec_name}::SchemaMigration"

                                Class.new(ActiveRecord::SchemaMigration) do
                                  define_singleton_method(:name) { schema_migration_name }
                                  define_singleton_method(:to_s) { schema_migration_name }

                                  self.connection_specification_name = spec_name
                                end
                              end
      end

      def prepared_statements?
        @prepared_statements && !prepared_statements_disabled_cache.include?(object_id)
      end
      alias :prepared_statements :prepared_statements?

      def prepared_statements_disabled_cache # :nodoc:
        ActiveSupport::IsolatedExecutionState[:active_record_prepared_statements_disabled_cache] ||= Set.new
      end

      class Version
        include Comparable

        attr_reader :full_version_string

        def initialize(version_string, full_version_string = nil)
          @version = version_string.split(".").map(&:to_i)
          @full_version_string = full_version_string
        end

        def <=>(version_string)
          @version <=> version_string.split(".").map(&:to_i)
        end

        def to_s
          @version.join(".")
        end
      end

      def valid_type?(type) # :nodoc:
        !native_database_types[type].nil?
      end

      # this method must only be called while holding connection pool's mutex
      def lease
        if in_use?
          msg = +"Cannot lease connection, "
          if @owner == ActiveSupport::IsolatedExecutionState.context
            msg << "it is already leased by the current thread."
          else
            msg << "it is already in use by a different thread: #{@owner}. " \
                   "Current thread: #{ActiveSupport::IsolatedExecutionState.context}."
          end
          raise ActiveRecordError, msg
        end

        @owner = ActiveSupport::IsolatedExecutionState.context
      end

      def connection_class # :nodoc:
        @pool.connection_class
      end

      # The role (e.g. +:writing+) for the current connection. In a
      # non-multi role application, +:writing+ is returned.
      def role
        @pool.role
      end

      # The shard (e.g. +:default+) for the current connection. In
      # a non-sharded application, +:default+ is returned.
      def shard
        @pool.shard
      end

      def schema_cache
        @pool.get_schema_cache(self)
      end

      def schema_cache=(cache)
        cache.connection = self
        @pool.set_schema_cache(cache)
      end

      # this method must only be called while holding connection pool's mutex
      def expire
        if in_use?
          if @owner != ActiveSupport::IsolatedExecutionState.context
            raise ActiveRecordError, "Cannot expire connection, " \
              "it is owned by a different thread: #{@owner}. " \
              "Current thread: #{ActiveSupport::IsolatedExecutionState.context}."
          end

          @idle_since = Process.clock_gettime(Process::CLOCK_MONOTONIC)
          @owner = nil
        else
          raise ActiveRecordError, "Cannot expire connection, it is not currently leased."
        end
      end

      # this method must only be called while holding connection pool's mutex (and a desire for segfaults)
      def steal! # :nodoc:
        if in_use?
          if @owner != ActiveSupport::IsolatedExecutionState.context
            pool.send :remove_connection_from_thread_cache, self, @owner

            @owner = ActiveSupport::IsolatedExecutionState.context
          end
        else
          raise ActiveRecordError, "Cannot steal connection, it is not currently leased."
        end
      end

      # Seconds since this connection was returned to the pool
      def seconds_idle # :nodoc:
        return 0 if in_use?
        Process.clock_gettime(Process::CLOCK_MONOTONIC) - @idle_since
      end

      def unprepared_statement
        cache = prepared_statements_disabled_cache.add?(object_id) if @prepared_statements
        yield
      ensure
        cache&.delete(object_id)
      end

      # Returns the human-readable name of the adapter. Use mixed case - one
      # can always use downcase if needed.
      def adapter_name
        self.class::ADAPTER_NAME
      end

      # Does the database for this adapter exist?
      def self.database_exists?(config)
        raise NotImplementedError
      end

      # Does this adapter support DDL rollbacks in transactions? That is, would
      # CREATE TABLE or ALTER TABLE get rolled back by a transaction?
      def supports_ddl_transactions?
        false
      end

      def supports_bulk_alter?
        false
      end

      # Does this adapter support savepoints?
      def supports_savepoints?
        false
      end

      # Do TransactionRollbackErrors on savepoints affect the parent
      # transaction?
      def savepoint_errors_invalidate_transactions?
        false
      end

      def supports_restart_db_transaction?
        false
      end

      # Does this adapter support application-enforced advisory locking?
      def supports_advisory_locks?
        false
      end

      # Should primary key values be selected from their corresponding
      # sequence before the insert statement? If true, next_sequence_value
      # is called before each insert to set the record's primary key.
      def prefetch_primary_key?(table_name = nil)
        false
      end

      def supports_partitioned_indexes?
        false
      end

      # Does this adapter support index sort order?
      def supports_index_sort_order?
        false
      end

      # Does this adapter support partial indices?
      def supports_partial_index?
        false
      end

      # Does this adapter support expression indices?
      def supports_expression_index?
        false
      end

      # Does this adapter support explain?
      def supports_explain?
        false
      end

      # Does this adapter support setting the isolation level for a transaction?
      def supports_transaction_isolation?
        false
      end

      # Does this adapter support database extensions?
      def supports_extensions?
        false
      end

      # Does this adapter support creating indexes in the same statement as
      # creating the table?
      def supports_indexes_in_create?
        false
      end

      # Does this adapter support creating foreign key constraints?
      def supports_foreign_keys?
        false
      end

      # Does this adapter support creating invalid constraints?
      def supports_validate_constraints?
        false
      end

      # Does this adapter support creating deferrable constraints?
      def supports_deferrable_constraints?
        false
      end

      # Does this adapter support creating check constraints?
      def supports_check_constraints?
        false
      end

      # Does this adapter support views?
      def supports_views?
        false
      end

      # Does this adapter support materialized views?
      def supports_materialized_views?
        false
      end

      # Does this adapter support datetime with precision?
      def supports_datetime_with_precision?
        false
      end

      # Does this adapter support json data type?
      def supports_json?
        false
      end

      # Does this adapter support metadata comments on database objects (tables, columns, indexes)?
      def supports_comments?
        false
      end

      # Can comments for tables, columns, and indexes be specified in create/alter table statements?
      def supports_comments_in_create?
        false
      end

      # Does this adapter support virtual columns?
      def supports_virtual_columns?
        false
      end

      # Does this adapter support foreign/external tables?
      def supports_foreign_tables?
        false
      end

      # Does this adapter support optimizer hints?
      def supports_optimizer_hints?
        false
      end

      def supports_common_table_expressions?
        false
      end

      def supports_lazy_transactions?
        false
      end

      def supports_insert_returning?
        false
      end

      def supports_insert_on_duplicate_skip?
        false
      end

      def supports_insert_on_duplicate_update?
        false
      end

      def supports_insert_conflict_target?
        false
      end

      def supports_concurrent_connections?
        true
      end

      def async_enabled? # :nodoc:
        supports_concurrent_connections? &&
          !ActiveRecord.async_query_executor.nil? && !pool.async_executor.nil?
      end

      # This is meant to be implemented by the adapters that support extensions
      def disable_extension(name)
      end

      # This is meant to be implemented by the adapters that support extensions
      def enable_extension(name)
      end

      # This is meant to be implemented by the adapters that support custom enum types
      def create_enum(*) # :nodoc:
      end

      def advisory_locks_enabled? # :nodoc:
        supports_advisory_locks? && @advisory_locks_enabled
      end

      # This is meant to be implemented by the adapters that support advisory
      # locks
      #
      # Return true if we got the lock, otherwise false
      def get_advisory_lock(lock_id) # :nodoc:
      end

      # This is meant to be implemented by the adapters that support advisory
      # locks.
      #
      # Return true if we released the lock, otherwise false
      def release_advisory_lock(lock_id) # :nodoc:
      end

      # A list of extensions, to be filled in by adapters that support them.
      def extensions
        []
      end

      # A list of index algorithms, to be filled by adapters that support them.
      def index_algorithms
        {}
      end

      # REFERENTIAL INTEGRITY ====================================

      # Override to turn off referential integrity while executing <tt>&block</tt>.
      def disable_referential_integrity
        yield
      end

      # Override to check all foreign key constraints in a database.
      def all_foreign_keys_valid?
        true
      end

      # CONNECTION MANAGEMENT ====================================

      # Checks whether the connection to the database is still active. This includes
      # checking whether the database is actually capable of responding, i.e. whether
      # the connection isn't stale.
      def active?
      end

      # Disconnects from the database if already connected, and establishes a
      # new connection with the database. Implementors should call super
      # immediately after establishing the new connection (and while still
      # holding @lock).
      def reconnect!(restore_transactions: false)
        reset_transaction(restore: restore_transactions) do
          clear_cache!(new_connection: true)
          configure_connection
        end
      end

      # Disconnects from the database if already connected. Otherwise, this
      # method does nothing.
      def disconnect!
        clear_cache!(new_connection: true)
        reset_transaction
      end

      # Immediately forget this connection ever existed. Unlike disconnect!,
      # this will not communicate with the server.
      #
      # After calling this method, the behavior of all other methods becomes
      # undefined. This is called internally just before a forked process gets
      # rid of a connection that belonged to its parent.
      def discard!
        # This should be overridden by concrete adapters.
        #
        # Prevent @raw_connection's finalizer from touching the socket, or
        # otherwise communicating with its server, when it is collected.
        if schema_cache.connection == self
          schema_cache.connection = nil
        end
      end

      # Reset the state of this connection, directing the DBMS to clear
      # transactions and other connection-related server-side state. Usually a
      # database-dependent operation.
      #
      # If a database driver or protocol does not support such a feature,
      # implementors may alias this to #reconnect!. Otherwise, implementors
      # should call super immediately after resetting the connection (and while
      # still holding @lock).
      def reset!
        clear_cache!(new_connection: true)
        reset_transaction
        configure_connection
      end

      # Removes the connection from the pool and disconnect it.
      def throw_away!
        pool.remove self
        disconnect!
      end

      # Clear any caching the database adapter may be doing.
      def clear_cache!(new_connection: false)
        if @statements
          @lock.synchronize do
            if new_connection
              @statements.reset
            else
              @statements.clear
            end
          end
        end
      end

      # Returns true if its required to reload the connection between requests for development mode.
      def requires_reloading?
        false
      end

      # Checks whether the connection to the database is still active (i.e. not stale).
      # This is done under the hood by calling #active?. If the connection
      # is no longer active, then this method will reconnect to the database.
      def verify!
        reconnect! unless active?
      end

      # Provides access to the underlying database driver for this adapter. For
      # example, this method returns a Mysql2::Client object in case of Mysql2Adapter,
      # and a PG::Connection object in case of PostgreSQLAdapter.
      #
      # This is useful for when you need to call a proprietary method such as
      # PostgreSQL's lo_* methods.
      def raw_connection
        disable_lazy_transactions!
        @raw_connection_dirty = true
        @raw_connection
      end

      def default_uniqueness_comparison(attribute, value) # :nodoc:
        attribute.eq(value)
      end

      def case_sensitive_comparison(attribute, value) # :nodoc:
        attribute.eq(value)
      end

      def case_insensitive_comparison(attribute, value) # :nodoc:
        column = column_for_attribute(attribute)

        if can_perform_case_insensitive_comparison_for?(column)
          attribute.lower.eq(attribute.relation.lower(value))
        else
          attribute.eq(value)
        end
      end

      def can_perform_case_insensitive_comparison_for?(column)
        true
      end
      private :can_perform_case_insensitive_comparison_for?

      # Check the connection back in to the connection pool
      def close
        pool.checkin self
      end

      def default_index_type?(index) # :nodoc:
        index.using.nil?
      end

      # Called by ActiveRecord::InsertAll,
      # Passed an instance of ActiveRecord::InsertAll::Builder,
      # This method implements standard bulk inserts for all databases, but
      # should be overridden by adapters to implement common features with
      # non-standard syntax like handling duplicates or returning values.
      def build_insert_sql(insert) # :nodoc:
        if insert.skip_duplicates? || insert.update_duplicates?
          raise NotImplementedError, "#{self.class} should define `build_insert_sql` to implement adapter-specific logic for handling duplicates during INSERT"
        end

        "INSERT #{insert.into} #{insert.values_list}"
      end

      def get_database_version # :nodoc:
      end

      def database_version # :nodoc:
        schema_cache.database_version
      end

      def check_version # :nodoc:
      end

      # Returns the version identifier of the schema currently available in
      # the database. This is generally equal to the number of the highest-
      # numbered migration that has been executed, or 0 if no schema
      # information is present / the database is empty.
      def schema_version
        migration_context.current_version
      end

      def field_ordered_value(column, values) # :nodoc:
        node = Arel::Nodes::Case.new(column)
        values.each.with_index(1) do |value, order|
          node.when(value).then(order)
        end

        Arel::Nodes::Ascending.new(node.else(values.length + 1))
      end

      class << self
        def register_class_with_precision(mapping, key, klass, **kwargs) # :nodoc:
          mapping.register_type(key) do |*args|
            precision = extract_precision(args.last)
            klass.new(precision: precision, **kwargs)
          end
        end

        def extended_type_map(default_timezone:) # :nodoc:
          Type::TypeMap.new(self::TYPE_MAP).tap do |m|
            register_class_with_precision m, %r(\A[^\(]*time)i, Type::Time, timezone: default_timezone
            register_class_with_precision m, %r(\A[^\(]*datetime)i, Type::DateTime, timezone: default_timezone
            m.alias_type %r(\A[^\(]*timestamp)i, "datetime"
          end
        end

        private
          def initialize_type_map(m)
            register_class_with_limit m, %r(boolean)i,       Type::Boolean
            register_class_with_limit m, %r(char)i,          Type::String
            register_class_with_limit m, %r(binary)i,        Type::Binary
            register_class_with_limit m, %r(text)i,          Type::Text
            register_class_with_precision m, %r(date)i,      Type::Date
            register_class_with_precision m, %r(time)i,      Type::Time
            register_class_with_precision m, %r(datetime)i,  Type::DateTime
            register_class_with_limit m, %r(float)i,         Type::Float
            register_class_with_limit m, %r(int)i,           Type::Integer

            m.alias_type %r(blob)i,      "binary"
            m.alias_type %r(clob)i,      "text"
            m.alias_type %r(timestamp)i, "datetime"
            m.alias_type %r(numeric)i,   "decimal"
            m.alias_type %r(number)i,    "decimal"
            m.alias_type %r(double)i,    "float"

            m.register_type %r(^json)i, Type::Json.new

            m.register_type(%r(decimal)i) do |sql_type|
              scale = extract_scale(sql_type)
              precision = extract_precision(sql_type)

              if scale == 0
                # FIXME: Remove this class as well
                Type::DecimalWithoutScale.new(precision: precision)
              else
                Type::Decimal.new(precision: precision, scale: scale)
              end
            end
          end

          def register_class_with_limit(mapping, key, klass)
            mapping.register_type(key) do |*args|
              limit = extract_limit(args.last)
              klass.new(limit: limit)
            end
          end

          def extract_scale(sql_type)
            case sql_type
            when /\((\d+)\)/ then 0
            when /\((\d+)(,(\d+))\)/ then $3.to_i
            end
          end

          def extract_precision(sql_type)
            $1.to_i if sql_type =~ /\((\d+)(,\d+)?\)/
          end

          def extract_limit(sql_type)
            $1.to_i if sql_type =~ /\((.*)\)/
          end
      end

      TYPE_MAP = Type::TypeMap.new.tap { |m| initialize_type_map(m) }
      EXTENDED_TYPE_MAPS = Concurrent::Map.new

      private
        def reconnect_can_restore_state?
          transaction_manager.restorable? && !@raw_connection_dirty
        end

        def extended_type_map_key
          if @default_timezone
            { default_timezone: @default_timezone }
          end
        end

        def type_map
          if key = extended_type_map_key
            self.class::EXTENDED_TYPE_MAPS.compute_if_absent(key) do
              self.class.extended_type_map(**key)
            end
          else
            self.class::TYPE_MAP
          end
        end

        def translate_exception_class(e, sql, binds)
          message = "#{e.class.name}: #{e.message}"

          exception = translate_exception(
            e, message: message, sql: sql, binds: binds
          )
          exception.set_backtrace e.backtrace
          exception
        end

        def log(sql, name = "SQL", binds = [], type_casted_binds = [], statement_name = nil, async: false, &block) # :doc:
          @instrumenter.instrument(
            "sql.active_record",
            sql:               sql,
            name:              name,
            binds:             binds,
            type_casted_binds: type_casted_binds,
            statement_name:    statement_name,
            async:             async,
            connection:        self) do
            @lock.synchronize(&block)
          rescue => e
            raise translate_exception_class(e, sql, binds)
          end
        end

        def transform_query(sql)
          ActiveRecord.query_transformers.each do |transformer|
            sql = transformer.call(sql)
          end
          sql
        end

        def translate_exception(exception, message:, sql:, binds:)
          # override in derived class
          case exception
          when RuntimeError
            exception
          else
            ActiveRecord::StatementInvalid.new(message, sql: sql, binds: binds)
          end
        end

        def without_prepared_statement?(binds)
          !prepared_statements || binds.empty?
        end

        def column_for(table_name, column_name)
          column_name = column_name.to_s
          columns(table_name).detect { |c| c.name == column_name } ||
            raise(ActiveRecordError, "No such column: #{table_name}.#{column_name}")
        end

        def column_for_attribute(attribute)
          table_name = attribute.relation.name
          schema_cache.columns_hash(table_name)[attribute.name.to_s]
        end

        def collector
          if prepared_statements
            Arel::Collectors::Composite.new(
              Arel::Collectors::SQLString.new,
              Arel::Collectors::Bind.new,
            )
          else
            Arel::Collectors::SubstituteBinds.new(
              self,
              Arel::Collectors::SQLString.new,
            )
          end
        end

        def arel_visitor
          Arel::Visitors::ToSql.new(self)
        end

        def build_statement_pool
        end

        # Builds the result object.
        #
        # This is an internal hook to make possible connection adapters to build
        # custom result objects with connection-specific data.
        def build_result(columns:, rows:, column_types: {})
          ActiveRecord::Result.new(columns, rows, column_types)
        end

        # Perform any necessary initialization upon the newly-established
        # @raw_connection -- this is the place to modify the adapter's
        # connection settings, run queries to configure any application-global
        # "session" variables, etc.
        #
        # Implementations may assume this method will only be called while
        # holding @lock (or from #initialize).
        def configure_connection
        end
    end
  end
end

abstract_mysql_adapter.rb

# frozen_string_literal: true

require "active_record/connection_adapters/abstract_adapter"
require "active_record/connection_adapters/statement_pool"
require "active_record/connection_adapters/mysql/column"
require "active_record/connection_adapters/mysql/explain_pretty_printer"
require "active_record/connection_adapters/mysql/quoting"
require "active_record/connection_adapters/mysql/schema_creation"
require "active_record/connection_adapters/mysql/schema_definitions"
require "active_record/connection_adapters/mysql/schema_dumper"
require "active_record/connection_adapters/mysql/schema_statements"
require "active_record/connection_adapters/mysql/type_metadata"

module ActiveRecord
  module ConnectionAdapters
    class AbstractMysqlAdapter < AbstractAdapter
      include MySQL::Quoting
      include MySQL::SchemaStatements

      ##
      # :singleton-method:
      # By default, the Mysql2Adapter will consider all columns of type <tt>tinyint(1)</tt>
      # as boolean. If you wish to disable this emulation you can add the following line
      # to your application.rb file:
      #
      #   ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans = false
      class_attribute :emulate_booleans, default: true

      NATIVE_DATABASE_TYPES = {
        primary_key: "bigint auto_increment PRIMARY KEY",
        string:      { name: "varchar", limit: 255 },
        text:        { name: "text" },
        integer:     { name: "int", limit: 4 },
        bigint:      { name: "bigint" },
        float:       { name: "float", limit: 24 },
        decimal:     { name: "decimal" },
        datetime:    { name: "datetime" },
        timestamp:   { name: "timestamp" },
        time:        { name: "time" },
        date:        { name: "date" },
        binary:      { name: "blob" },
        blob:        { name: "blob" },
        boolean:     { name: "tinyint", limit: 1 },
        json:        { name: "json" },
      }

      class StatementPool < ConnectionAdapters::StatementPool # :nodoc:
        private
          def dealloc(stmt)
            stmt.close
          end
      end

      def initialize(connection, logger, connection_options, config)
        super(connection, logger, config)
      end

      def get_database_version # :nodoc:
        full_version_string = get_full_version
        version_string = version_string(full_version_string)
        Version.new(version_string, full_version_string)
      end

      def mariadb? # :nodoc:
        /mariadb/i.match?(full_version)
      end

      def supports_bulk_alter?
        true
      end

      def supports_index_sort_order?
        !mariadb? && database_version >= "8.0.1"
      end

      def supports_expression_index?
        !mariadb? && database_version >= "8.0.13"
      end

      def supports_transaction_isolation?
        true
      end

      def supports_restart_db_transaction?
        true
      end

      def supports_explain?
        true
      end

      def supports_indexes_in_create?
        true
      end

      def supports_foreign_keys?
        true
      end

      def supports_check_constraints?
        if mariadb?
          database_version >= "10.2.1"
        else
          database_version >= "8.0.16"
        end
      end

      def supports_views?
        true
      end

      def supports_datetime_with_precision?
        mariadb? || database_version >= "5.6.4"
      end

      def supports_virtual_columns?
        mariadb? || database_version >= "5.7.5"
      end

      # See https://dev.mysql.com/doc/refman/en/optimizer-hints.html for more details.
      def supports_optimizer_hints?
        !mariadb? && database_version >= "5.7.7"
      end

      def supports_common_table_expressions?
        if mariadb?
          database_version >= "10.2.1"
        else
          database_version >= "8.0.1"
        end
      end

      def supports_advisory_locks?
        true
      end

      def supports_insert_on_duplicate_skip?
        true
      end

      def supports_insert_on_duplicate_update?
        true
      end

      def field_ordered_value(column, values) # :nodoc:
        field = Arel::Nodes::NamedFunction.new("FIELD", [column, values.reverse])
        Arel::Nodes::Descending.new(field)
      end

      def get_advisory_lock(lock_name, timeout = 0) # :nodoc:
        query_value("SELECT GET_LOCK(#{quote(lock_name.to_s)}, #{timeout})") == 1
      end

      def release_advisory_lock(lock_name) # :nodoc:
        query_value("SELECT RELEASE_LOCK(#{quote(lock_name.to_s)})") == 1
      end

      def native_database_types
        NATIVE_DATABASE_TYPES
      end

      def index_algorithms
        {
          default: "ALGORITHM = DEFAULT",
          copy:    "ALGORITHM = COPY",
          inplace: "ALGORITHM = INPLACE",
          instant: "ALGORITHM = INSTANT",
        }
      end

      # HELPER METHODS ===========================================

      # The two drivers have slightly different ways of yielding hashes of results, so
      # this method must be implemented to provide a uniform interface.
      def each_hash(result) # :nodoc:
        raise NotImplementedError
      end

      # Must return the MySQL error number from the exception, if the exception has an
      # error number.
      def error_number(exception) # :nodoc:
        raise NotImplementedError
      end

      # REFERENTIAL INTEGRITY ====================================

      def disable_referential_integrity # :nodoc:
        old = query_value("SELECT @@FOREIGN_KEY_CHECKS")

        begin
          update("SET FOREIGN_KEY_CHECKS = 0")
          yield
        ensure
          update("SET FOREIGN_KEY_CHECKS = #{old}")
        end
      end

      #--
      # DATABASE STATEMENTS ======================================
      #++

      # Executes the SQL statement in the context of this connection.
      def execute(sql, name = nil, async: false)
        raw_execute(sql, name, async: async)
      end

      # Mysql2Adapter doesn't have to free a result after using it, but we use this method
      # to write stuff in an abstract way without concerning ourselves about whether it
      # needs to be explicitly freed or not.
      def execute_and_free(sql, name = nil, async: false) # :nodoc:
        yield execute(sql, name, async: async)
      end

      def begin_db_transaction # :nodoc:
        execute("BEGIN", "TRANSACTION")
      end

      def begin_isolated_db_transaction(isolation) # :nodoc:
        execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
        begin_db_transaction
      end

      def commit_db_transaction # :nodoc:
        execute("COMMIT", "TRANSACTION")
      end

      def exec_rollback_db_transaction # :nodoc:
        execute("ROLLBACK", "TRANSACTION")
      end

      def exec_restart_db_transaction # :nodoc:
        execute("ROLLBACK AND CHAIN", "TRANSACTION")
      end

      def empty_insert_statement_value(primary_key = nil) # :nodoc:
        "VALUES ()"
      end

      # SCHEMA STATEMENTS ========================================

      # Drops the database specified on the +name+ attribute
      # and creates it again using the provided +options+.
      def recreate_database(name, options = {})
        drop_database(name)
        sql = create_database(name, options)
        reconnect!
        sql
      end

      # Create a new MySQL database with optional <tt>:charset</tt> and <tt>:collation</tt>.
      # Charset defaults to utf8mb4.
      #
      # Example:
      #   create_database 'charset_test', charset: 'latin1', collation: 'latin1_bin'
      #   create_database 'matt_development'
      #   create_database 'matt_development', charset: :big5
      def create_database(name, options = {})
        if options[:collation]
          execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT COLLATE #{quote_table_name(options[:collation])}"
        elsif options[:charset]
          execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset])}"
        elsif row_format_dynamic_by_default?
          execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET `utf8mb4`"
        else
          raise "Configure a supported :charset and ensure innodb_large_prefix is enabled to support indexes on varchar(255) string columns."
        end
      end

      # Drops a MySQL database.
      #
      # Example:
      #   drop_database('sebastian_development')
      def drop_database(name) # :nodoc:
        execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
      end

      def current_database
        query_value("SELECT database()", "SCHEMA")
      end

      # Returns the database character set.
      def charset
        show_variable "character_set_database"
      end

      # Returns the database collation strategy.
      def collation
        show_variable "collation_database"
      end

      def table_comment(table_name) # :nodoc:
        scope = quoted_scope(table_name)

        query_value(<<~SQL, "SCHEMA").presence
          SELECT table_comment
          FROM information_schema.tables
          WHERE table_schema = #{scope[:schema]}
            AND table_name = #{scope[:name]}
        SQL
      end

      def change_table_comment(table_name, comment_or_changes) # :nodoc:
        comment = extract_new_comment_value(comment_or_changes)
        comment = "" if comment.nil?
        execute("ALTER TABLE #{quote_table_name(table_name)} COMMENT #{quote(comment)}")
      end

      # Renames a table.
      #
      # Example:
      #   rename_table('octopuses', 'octopi')
      def rename_table(table_name, new_name)
        schema_cache.clear_data_source_cache!(table_name.to_s)
        schema_cache.clear_data_source_cache!(new_name.to_s)
        execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
        rename_table_indexes(table_name, new_name)
      end

      # Drops a table from the database.
      #
      # [<tt>:force</tt>]
      #   Set to +:cascade+ to drop dependent objects as well.
      #   Defaults to false.
      # [<tt>:if_exists</tt>]
      #   Set to +true+ to only drop the table if it exists.
      #   Defaults to false.
      # [<tt>:temporary</tt>]
      #   Set to +true+ to drop temporary table.
      #   Defaults to false.
      #
      # Although this command ignores most +options+ and the block if one is given,
      # it can be helpful to provide these in a migration's +change+ method so it can be reverted.
      # In that case, +options+ and the block will be used by create_table.
      def drop_table(table_name, **options)
        schema_cache.clear_data_source_cache!(table_name.to_s)
        execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
      end

      def rename_index(table_name, old_name, new_name)
        if supports_rename_index?
          validate_index_length!(table_name, new_name)

          execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
        else
          super
        end
      end

      def change_column_default(table_name, column_name, default_or_changes) # :nodoc:
        default = extract_new_default_value(default_or_changes)
        change_column table_name, column_name, nil, default: default
      end

      def change_column_null(table_name, column_name, null, default = nil) # :nodoc:
        unless null || default.nil?
          execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
        end

        change_column table_name, column_name, nil, null: null
      end

      def change_column_comment(table_name, column_name, comment_or_changes) # :nodoc:
        comment = extract_new_comment_value(comment_or_changes)
        change_column table_name, column_name, nil, comment: comment
      end

      def change_column(table_name, column_name, type, **options) # :nodoc:
        execute("ALTER TABLE #{quote_table_name(table_name)} #{change_column_for_alter(table_name, column_name, type, **options)}")
      end

      def rename_column(table_name, column_name, new_column_name) # :nodoc:
        execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_for_alter(table_name, column_name, new_column_name)}")
        rename_column_indexes(table_name, column_name, new_column_name)
      end

      def add_index(table_name, column_name, **options) # :nodoc:
        index, algorithm, if_not_exists = add_index_options(table_name, column_name, **options)

        return if if_not_exists && index_exists?(table_name, column_name, name: index.name)

        create_index = CreateIndexDefinition.new(index, algorithm)
        execute schema_creation.accept(create_index)
      end

      def add_sql_comment!(sql, comment) # :nodoc:
        sql << " COMMENT #{quote(comment)}" if comment.present?
        sql
      end

      def foreign_keys(table_name)
        raise ArgumentError unless table_name.present?

        scope = quoted_scope(table_name)

        fk_info = exec_query(<<~SQL, "SCHEMA")
          SELECT fk.referenced_table_name AS 'to_table',
                 fk.referenced_column_name AS 'primary_key',
                 fk.column_name AS 'column',
                 fk.constraint_name AS 'name',
                 rc.update_rule AS 'on_update',
                 rc.delete_rule AS 'on_delete'
          FROM information_schema.referential_constraints rc
          JOIN information_schema.key_column_usage fk
          USING (constraint_schema, constraint_name)
          WHERE fk.referenced_column_name IS NOT NULL
            AND fk.table_schema = #{scope[:schema]}
            AND fk.table_name = #{scope[:name]}
            AND rc.constraint_schema = #{scope[:schema]}
            AND rc.table_name = #{scope[:name]}
        SQL

        fk_info.map do |row|
          options = {
            column: row["column"],
            name: row["name"],
            primary_key: row["primary_key"]
          }

          options[:on_update] = extract_foreign_key_action(row["on_update"])
          options[:on_delete] = extract_foreign_key_action(row["on_delete"])

          ForeignKeyDefinition.new(table_name, row["to_table"], options)
        end
      end

      def check_constraints(table_name)
        if supports_check_constraints?
          scope = quoted_scope(table_name)

          sql = <<~SQL
            SELECT cc.constraint_name AS 'name',
                  cc.check_clause AS 'expression'
            FROM information_schema.check_constraints cc
            JOIN information_schema.table_constraints tc
            USING (constraint_schema, constraint_name)
            WHERE tc.table_schema = #{scope[:schema]}
              AND tc.table_name = #{scope[:name]}
              AND cc.constraint_schema = #{scope[:schema]}
          SQL
          sql += " AND cc.table_name = #{scope[:name]}" if mariadb?

          chk_info = exec_query(sql, "SCHEMA")

          chk_info.map do |row|
            options = {
              name: row["name"]
            }
            expression = row["expression"]
            expression = expression[1..-2] unless mariadb? # remove parentheses added by mysql
            CheckConstraintDefinition.new(table_name, expression, options)
          end
        else
          raise NotImplementedError
        end
      end

      def table_options(table_name) # :nodoc:
        create_table_info = create_table_info(table_name)

        # strip create_definitions and partition_options
        # Be aware that `create_table_info` might not include any table options due to `NO_TABLE_OPTIONS` sql mode.
        raw_table_options = create_table_info.sub(/\A.*\n\) ?/m, "").sub(/\n\/\*!.*\*\/\n\z/m, "").strip

        return if raw_table_options.empty?

        table_options = {}

        if / DEFAULT CHARSET=(?<charset>\w+)(?: COLLATE=(?<collation>\w+))?/ =~ raw_table_options
          raw_table_options = $` + $' # before part + after part
          table_options[:charset] = charset
          table_options[:collation] = collation if collation
        end

        # strip AUTO_INCREMENT
        raw_table_options.sub!(/(ENGINE=\w+)(?: AUTO_INCREMENT=\d+)/, '\1')

        # strip COMMENT
        if raw_table_options.sub!(/ COMMENT='.+'/, "")
          table_options[:comment] = table_comment(table_name)
        end

        table_options[:options] = raw_table_options unless raw_table_options == "ENGINE=InnoDB"
        table_options
      end

      # SHOW VARIABLES LIKE 'name'
      def show_variable(name)
        query_value("SELECT @@#{name}", "SCHEMA")
      rescue ActiveRecord::StatementInvalid
        nil
      end

      def primary_keys(table_name) # :nodoc:
        raise ArgumentError unless table_name.present?

        scope = quoted_scope(table_name)

        query_values(<<~SQL, "SCHEMA")
          SELECT column_name
          FROM information_schema.statistics
          WHERE index_name = 'PRIMARY'
            AND table_schema = #{scope[:schema]}
            AND table_name = #{scope[:name]}
          ORDER BY seq_in_index
        SQL
      end

      def case_sensitive_comparison(attribute, value) # :nodoc:
        column = column_for_attribute(attribute)

        if column.collation && !column.case_sensitive?
          attribute.eq(Arel::Nodes::Bin.new(value))
        else
          super
        end
      end

      def can_perform_case_insensitive_comparison_for?(column)
        column.case_sensitive?
      end
      private :can_perform_case_insensitive_comparison_for?

      # In MySQL 5.7.5 and up, ONLY_FULL_GROUP_BY affects handling of queries that use
      # DISTINCT and ORDER BY. It requires the ORDER BY columns in the select list for
      # distinct queries, and requires that the ORDER BY include the distinct column.
      # See https://dev.mysql.com/doc/refman/en/group-by-handling.html
      def columns_for_distinct(columns, orders) # :nodoc:
        order_columns = orders.compact_blank.map { |s|
          # Convert Arel node to string
          s = visitor.compile(s) unless s.is_a?(String)
          # Remove any ASC/DESC modifiers
          s.gsub(/\s+(?:ASC|DESC)\b/i, "")
        }.compact_blank.map.with_index { |column, i| "#{column} AS alias_#{i}" }

        (order_columns << super).join(", ")
      end

      def strict_mode?
        self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
      end

      def default_index_type?(index) # :nodoc:
        index.using == :btree || super
      end

      def build_insert_sql(insert) # :nodoc:
        sql = +"INSERT #{insert.into} #{insert.values_list}"

        if insert.skip_duplicates?
          no_op_column = quote_column_name(insert.keys.first)
          sql << " ON DUPLICATE KEY UPDATE #{no_op_column}=#{no_op_column}"
        elsif insert.update_duplicates?
          sql << " ON DUPLICATE KEY UPDATE "
          if insert.raw_update_sql?
            sql << insert.raw_update_sql
          else
            sql << insert.touch_model_timestamps_unless { |column| "#{column}<=>VALUES(#{column})" }
            sql << insert.updatable_columns.map { |column| "#{column}=VALUES(#{column})" }.join(",")
          end
        end

        sql
      end

      def check_version # :nodoc:
        if database_version < "5.5.8"
          raise "Your version of MySQL (#{database_version}) is too old. Active Record supports MySQL >= 5.5.8."
        end
      end

      class << self
        def extended_type_map(default_timezone: nil, emulate_booleans:) # :nodoc:
          super(default_timezone: default_timezone).tap do |m|
            if emulate_booleans
              m.register_type %r(^tinyint\(1\))i, Type::Boolean.new
            end
          end
        end

        private
          def initialize_type_map(m)
            super

            m.register_type(%r(char)i) do |sql_type|
              limit = extract_limit(sql_type)
              Type.lookup(:string, adapter: :mysql2, limit: limit)
            end

            m.register_type %r(tinytext)i,   Type::Text.new(limit: 2**8 - 1)
            m.register_type %r(tinyblob)i,   Type::Binary.new(limit: 2**8 - 1)
            m.register_type %r(text)i,       Type::Text.new(limit: 2**16 - 1)
            m.register_type %r(blob)i,       Type::Binary.new(limit: 2**16 - 1)
            m.register_type %r(mediumtext)i, Type::Text.new(limit: 2**24 - 1)
            m.register_type %r(mediumblob)i, Type::Binary.new(limit: 2**24 - 1)
            m.register_type %r(longtext)i,   Type::Text.new(limit: 2**32 - 1)
            m.register_type %r(longblob)i,   Type::Binary.new(limit: 2**32 - 1)
            m.register_type %r(^float)i,     Type::Float.new(limit: 24)
            m.register_type %r(^double)i,    Type::Float.new(limit: 53)

            register_integer_type m, %r(^bigint)i,    limit: 8
            register_integer_type m, %r(^int)i,       limit: 4
            register_integer_type m, %r(^mediumint)i, limit: 3
            register_integer_type m, %r(^smallint)i,  limit: 2
            register_integer_type m, %r(^tinyint)i,   limit: 1

            m.alias_type %r(year)i, "integer"
            m.alias_type %r(bit)i,  "binary"

            m.register_type %r(^enum)i, Type.lookup(:string, adapter: :mysql2)
            m.register_type %r(^set)i,  Type.lookup(:string, adapter: :mysql2)
          end

          def register_integer_type(mapping, key, **options)
            mapping.register_type(key) do |sql_type|
              if /\bunsigned\b/.match?(sql_type)
                Type::UnsignedInteger.new(**options)
              else
                Type::Integer.new(**options)
              end
            end
          end

          def extract_precision(sql_type)
            if /\A(?:date)?time(?:stamp)?\b/.match?(sql_type)
              super || 0
            else
              super
            end
          end
      end

      TYPE_MAP = Type::TypeMap.new.tap { |m| initialize_type_map(m) }
      EXTENDED_TYPE_MAPS = Concurrent::Map.new
      EMULATE_BOOLEANS_TRUE = { emulate_booleans: true }.freeze

      private
        def extended_type_map_key
          if @default_timezone
            { default_timezone: @default_timezone, emulate_booleans: emulate_booleans }
          elsif emulate_booleans
            EMULATE_BOOLEANS_TRUE
          end
        end

        def raw_execute(sql, name, async: false)
          materialize_transactions
          mark_transaction_written_if_write(sql)

          log(sql, name, async: async) do
            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
              @raw_connection.query(sql)
            end
          end
        end

        # See https://dev.mysql.com/doc/mysql-errors/en/server-error-reference.html
        ER_DB_CREATE_EXISTS     = 1007
        ER_FILSORT_ABORT        = 1028
        ER_DUP_ENTRY            = 1062
        ER_NOT_NULL_VIOLATION   = 1048
        ER_NO_REFERENCED_ROW    = 1216
        ER_ROW_IS_REFERENCED    = 1217
        ER_DO_NOT_HAVE_DEFAULT  = 1364
        ER_ROW_IS_REFERENCED_2  = 1451
        ER_NO_REFERENCED_ROW_2  = 1452
        ER_DATA_TOO_LONG        = 1406
        ER_OUT_OF_RANGE         = 1264
        ER_LOCK_DEADLOCK        = 1213
        ER_CANNOT_ADD_FOREIGN   = 1215
        ER_CANNOT_CREATE_TABLE  = 1005
        ER_LOCK_WAIT_TIMEOUT    = 1205
        ER_QUERY_INTERRUPTED    = 1317
        ER_QUERY_TIMEOUT        = 3024
        ER_FK_INCOMPATIBLE_COLUMNS = 3780

        def translate_exception(exception, message:, sql:, binds:)
          case error_number(exception)
          when nil
            if exception.message.match?(/MySQL client is not connected/i)
              ConnectionNotEstablished.new(exception)
            else
              super
            end
          when ER_DB_CREATE_EXISTS
            DatabaseAlreadyExists.new(message, sql: sql, binds: binds)
          when ER_DUP_ENTRY
            RecordNotUnique.new(message, sql: sql, binds: binds)
          when ER_NO_REFERENCED_ROW, ER_ROW_IS_REFERENCED, ER_ROW_IS_REFERENCED_2, ER_NO_REFERENCED_ROW_2
            InvalidForeignKey.new(message, sql: sql, binds: binds)
          when ER_CANNOT_ADD_FOREIGN, ER_FK_INCOMPATIBLE_COLUMNS
            mismatched_foreign_key(message, sql: sql, binds: binds)
          when ER_CANNOT_CREATE_TABLE
            if message.include?("errno: 150")
              mismatched_foreign_key(message, sql: sql, binds: binds)
            else
              super
            end
          when ER_DATA_TOO_LONG
            ValueTooLong.new(message, sql: sql, binds: binds)
          when ER_OUT_OF_RANGE
            RangeError.new(message, sql: sql, binds: binds)
          when ER_NOT_NULL_VIOLATION, ER_DO_NOT_HAVE_DEFAULT
            NotNullViolation.new(message, sql: sql, binds: binds)
          when ER_LOCK_DEADLOCK
            Deadlocked.new(message, sql: sql, binds: binds)
          when ER_LOCK_WAIT_TIMEOUT
            LockWaitTimeout.new(message, sql: sql, binds: binds)
          when ER_QUERY_TIMEOUT, ER_FILSORT_ABORT
            StatementTimeout.new(message, sql: sql, binds: binds)
          when ER_QUERY_INTERRUPTED
            QueryCanceled.new(message, sql: sql, binds: binds)
          else
            super
          end
        end

        def change_column_for_alter(table_name, column_name, type, **options)
          column = column_for(table_name, column_name)
          type ||= column.sql_type

          unless options.key?(:default)
            options[:default] = column.default
          end

          unless options.key?(:null)
            options[:null] = column.null
          end

          unless options.key?(:comment)
            options[:comment] = column.comment
          end

          unless options.key?(:auto_increment)
            options[:auto_increment] = column.auto_increment?
          end

          td = create_table_definition(table_name)
          cd = td.new_column_definition(column.name, type, **options)
          schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
        end

        def rename_column_for_alter(table_name, column_name, new_column_name)
          return rename_column_sql(table_name, column_name, new_column_name) if supports_rename_column?

          column  = column_for(table_name, column_name)
          options = {
            default: column.default,
            null: column.null,
            auto_increment: column.auto_increment?,
            comment: column.comment
          }

          current_type = exec_query("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE #{quote(column_name)}", "SCHEMA").first["Type"]
          td = create_table_definition(table_name)
          cd = td.new_column_definition(new_column_name, current_type, **options)
          schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
        end

        def add_index_for_alter(table_name, column_name, **options)
          index, algorithm, _ = add_index_options(table_name, column_name, **options)
          algorithm = ", #{algorithm}" if algorithm

          "ADD #{schema_creation.accept(index)}#{algorithm}"
        end

        def remove_index_for_alter(table_name, column_name = nil, **options)
          index_name = index_name_for_remove(table_name, column_name, options)
          "DROP INDEX #{quote_column_name(index_name)}"
        end

        def supports_rename_index?
          if mariadb?
            database_version >= "10.5.2"
          else
            database_version >= "5.7.6"
          end
        end

        def supports_rename_column?
          if mariadb?
            database_version >= "10.5.2"
          else
            database_version >= "8.0.3"
          end
        end

        def configure_connection
          variables = @config.fetch(:variables, {}).stringify_keys

          # By default, MySQL 'where id is null' selects the last inserted id; Turn this off.
          variables["sql_auto_is_null"] = 0

          # Increase timeout so the server doesn't disconnect us.
          wait_timeout = self.class.type_cast_config_to_integer(@config[:wait_timeout])
          wait_timeout = 2147483 unless wait_timeout.is_a?(Integer)
          variables["wait_timeout"] = wait_timeout

          defaults = [":default", :default].to_set

          # Make MySQL reject illegal values rather than truncating or blanking them, see
          # https://dev.mysql.com/doc/refman/en/sql-mode.html#sqlmode_strict_all_tables
          # If the user has provided another value for sql_mode, don't replace it.
          if sql_mode = variables.delete("sql_mode")
            sql_mode = quote(sql_mode)
          elsif !defaults.include?(strict_mode?)
            if strict_mode?
              sql_mode = "CONCAT(@@sql_mode, ',STRICT_ALL_TABLES')"
            else
              sql_mode = "REPLACE(@@sql_mode, 'STRICT_TRANS_TABLES', '')"
              sql_mode = "REPLACE(#{sql_mode}, 'STRICT_ALL_TABLES', '')"
              sql_mode = "REPLACE(#{sql_mode}, 'TRADITIONAL', '')"
            end
            sql_mode = "CONCAT(#{sql_mode}, ',NO_AUTO_VALUE_ON_ZERO')"
          end
          sql_mode_assignment = "@@SESSION.sql_mode = #{sql_mode}, " if sql_mode

          # NAMES does not have an equals sign, see
          # https://dev.mysql.com/doc/refman/en/set-names.html
          # (trailing comma because variable_assignments will always have content)
          if @config[:encoding]
            encoding = +"NAMES #{@config[:encoding]}"
            encoding << " COLLATE #{@config[:collation]}" if @config[:collation]
            encoding << ", "
          end

          # Gather up all of the SET variables...
          variable_assignments = variables.filter_map do |k, v|
            if defaults.include?(v)
              "@@SESSION.#{k} = DEFAULT" # Sets the value to the global or compile default
            elsif !v.nil?
              "@@SESSION.#{k} = #{quote(v)}"
            end
          end.join(", ")

          # ...and send them all in one query
          execute("SET #{encoding} #{sql_mode_assignment} #{variable_assignments}", "SCHEMA")
        end

        def column_definitions(table_name) # :nodoc:
          execute_and_free("SHOW FULL FIELDS FROM #{quote_table_name(table_name)}", "SCHEMA") do |result|
            each_hash(result)
          end
        end

        def create_table_info(table_name) # :nodoc:
          exec_query("SHOW CREATE TABLE #{quote_table_name(table_name)}", "SCHEMA").first["Create Table"]
        end

        def arel_visitor
          Arel::Visitors::MySQL.new(self)
        end

        def build_statement_pool
          StatementPool.new(self.class.type_cast_config_to_integer(@config[:statement_limit]))
        end

        def mismatched_foreign_key(message, sql:, binds:)
          match = %r/
            (?:CREATE|ALTER)\s+TABLE\s*(?:`?\w+`?\.)?`?(?<table>\w+)`?.+?
            FOREIGN\s+KEY\s*\(`?(?<foreign_key>\w+)`?\)\s*
            REFERENCES\s*(`?(?<target_table>\w+)`?)\s*\(`?(?<primary_key>\w+)`?\)
          /xmi.match(sql)

          options = {
            message: message,
            sql: sql,
            binds: binds,
          }

          if match
            options[:table] = match[:table]
            options[:foreign_key] = match[:foreign_key]
            options[:target_table] = match[:target_table]
            options[:primary_key] = match[:primary_key]
            options[:primary_key_column] = column_for(match[:target_table], match[:primary_key])
          end

          MismatchedForeignKey.new(**options)
        end

        def version_string(full_version_string)
          full_version_string.match(/^(?:5\.5\.5-)?(\d+\.\d+\.\d+)/)[1]
        end

        ActiveRecord::Type.register(:immutable_string, adapter: :mysql2) do |_, **args|
          Type::ImmutableString.new(true: "1", false: "0", **args)
        end
        ActiveRecord::Type.register(:string, adapter: :mysql2) do |_, **args|
          Type::String.new(true: "1", false: "0", **args)
        end
        ActiveRecord::Type.register(:unsigned_integer, Type::UnsignedInteger, adapter: :mysql2)
    end
  end
end

active_record.rb

# frozen_string_literal: true

require "rails/generators/named_base"
require "rails/generators/active_model"
require "rails/generators/active_record/migration"
require "active_record"

module ActiveRecord
  module Generators # :nodoc:
    class Base < Rails::Generators::NamedBase # :nodoc:
      include ActiveRecord::Generators::Migration

      # Set the current directory as base for the inherited generators.
      def self.base_root
        __dir__
      end
    end
  end
end

adapter_specific_registry.rb

# frozen_string_literal: true

module ActiveRecord
  # :stopdoc:
  module Type
    class AdapterSpecificRegistry # :nodoc:
      def initialize
        @registrations = []
      end

      def initialize_copy(other)
        @registrations = @registrations.dup
      end

      def add_modifier(options, klass, **args)
        registrations << DecorationRegistration.new(options, klass, **args)
      end

      def register(type_name, klass = nil, **options, &block)
        unless block_given?
          block = proc { |_, *args| klass.new(*args) }
          block.ruby2_keywords if block.respond_to?(:ruby2_keywords)
        end
        registrations << Registration.new(type_name, block, **options)
      end

      def lookup(symbol, *args, **kwargs)
        registration = find_registration(symbol, *args, **kwargs)

        if registration
          registration.call(self, symbol, *args, **kwargs)
        else
          raise ArgumentError, "Unknown type #{symbol.inspect}"
        end
      end

      private
        attr_reader :registrations

        def find_registration(symbol, *args, **kwargs)
          registrations
            .select { |registration| registration.matches?(symbol, *args, **kwargs) }
            .max
        end
    end

    class Registration # :nodoc:
      def initialize(name, block, adapter: nil, override: nil)
        @name = name
        @block = block
        @adapter = adapter
        @override = override
      end

      def call(_registry, *args, adapter: nil, **kwargs)
        block.call(*args, **kwargs)
      end

      def matches?(type_name, *args, **kwargs)
        type_name == name && matches_adapter?(**kwargs)
      end

      def <=>(other)
        if conflicts_with?(other)
          raise TypeConflictError.new("Type #{name} was registered for all
                                      adapters, but shadows a native type with
                                      the same name for #{other.adapter}".squish)
        end
        priority <=> other.priority
      end

      protected
        attr_reader :name, :block, :adapter, :override

        def priority
          result = 0
          if adapter
            result |= 1
          end
          if override
            result |= 2
          end
          result
        end

        def priority_except_adapter
          priority & 0b111111100
        end

      private
        def matches_adapter?(adapter: nil, **)
          (self.adapter.nil? || adapter == self.adapter)
        end

        def conflicts_with?(other)
          same_priority_except_adapter?(other) &&
            has_adapter_conflict?(other)
        end

        def same_priority_except_adapter?(other)
          priority_except_adapter == other.priority_except_adapter
        end

        def has_adapter_conflict?(other)
          (override.nil? && other.adapter) ||
            (adapter && other.override.nil?)
        end
    end

    class DecorationRegistration < Registration # :nodoc:
      def initialize(options, klass, adapter: nil)
        @options = options
        @klass = klass
        @adapter = adapter
      end

      def call(registry, *args, **kwargs)
        subtype = registry.lookup(*args, **kwargs.except(*options.keys))
        klass.new(subtype)
      end

      def matches?(*args, **kwargs)
        matches_adapter?(**kwargs) && matches_options?(**kwargs)
      end

      def priority
        super | 4
      end

      private
        attr_reader :options, :klass

        def matches_options?(**kwargs)
          options.all? do |key, value|
            kwargs[key] == value
          end
        end
    end
  end

  class TypeConflictError < StandardError # :nodoc:
  end
  # :startdoc:
end

aes256_gcm.rb

# frozen_string_literal: true

require "openssl"

module ActiveRecord
  module Encryption
    class Cipher
      # A 256-GCM cipher.
      #
      # By default it will use random initialization vectors. For deterministic encryption, it will use a SHA-256 hash of
      # the text to encrypt and the secret.
      #
      # See +Encryptor+
      class Aes256Gcm
        CIPHER_TYPE = "aes-256-gcm"

        class << self
          def key_length
            OpenSSL::Cipher.new(CIPHER_TYPE).key_len
          end

          def iv_length
            OpenSSL::Cipher.new(CIPHER_TYPE).iv_len
          end
        end

        # When iv not provided, it will generate a random iv on each encryption operation (default and
        # recommended operation)
        def initialize(secret, deterministic: false)
          @secret = secret
          @deterministic = deterministic
        end

        def encrypt(clear_text)
          # This code is extracted from +ActiveSupport::MessageEncryptor+. Not using it directly because we want to control
          # the message format and only serialize things once at the +ActiveRecord::Encryption::Message+ level. Also, this
          # cipher is prepared to deal with deterministic/non deterministic encryption modes.

          cipher = OpenSSL::Cipher.new(CIPHER_TYPE)
          cipher.encrypt
          cipher.key = @secret

          iv = generate_iv(cipher, clear_text)
          cipher.iv = iv

          encrypted_data = clear_text.empty? ? clear_text.dup : cipher.update(clear_text)
          encrypted_data << cipher.final

          ActiveRecord::Encryption::Message.new(payload: encrypted_data).tap do |message|
            message.headers.iv = iv
            message.headers.auth_tag = cipher.auth_tag
          end
        end

        def decrypt(encrypted_message)
          encrypted_data = encrypted_message.payload
          iv = encrypted_message.headers.iv
          auth_tag = encrypted_message.headers.auth_tag

          # Currently the OpenSSL bindings do not raise an error if auth_tag is
          # truncated, which would allow an attacker to easily forge it. See
          # https://github.com/ruby/openssl/issues/63
          raise ActiveRecord::Encryption::Errors::EncryptedContentIntegrity if auth_tag.nil? || auth_tag.bytes.length != 16

          cipher = OpenSSL::Cipher.new(CIPHER_TYPE)

          cipher.decrypt
          cipher.key = @secret
          cipher.iv = iv

          cipher.auth_tag = auth_tag
          cipher.auth_data = ""

          decrypted_data = encrypted_data.empty? ? encrypted_data : cipher.update(encrypted_data)
          decrypted_data << cipher.final

          decrypted_data
        rescue OpenSSL::Cipher::CipherError, TypeError, ArgumentError
          raise ActiveRecord::Encryption::Errors::Decryption
        end

        private
          def generate_iv(cipher, clear_text)
            if @deterministic
              generate_deterministic_iv(clear_text)
            else
              cipher.random_iv
            end
          end

          def generate_deterministic_iv(clear_text)
            OpenSSL::HMAC.digest(OpenSSL::Digest::SHA256.new, @secret, clear_text)[0, ActiveRecord::Encryption.cipher.iv_length]
          end
      end
    end
  end
end

aggregations.rb

# frozen_string_literal: true

module ActiveRecord
  # See ActiveRecord::Aggregations::ClassMethods for documentation
  module Aggregations
    def initialize_dup(*) # :nodoc:
      @aggregation_cache = {}
      super
    end

    def reload(*) # :nodoc:
      clear_aggregation_cache
      super
    end

    private
      def clear_aggregation_cache
        @aggregation_cache.clear if persisted?
      end

      def init_internals
        @aggregation_cache = {}
        super
      end

      # Active Record implements aggregation through a macro-like class method called #composed_of
      # for representing attributes as value objects. It expresses relationships like "Account [is]
      # composed of Money [among other things]" or "Person [is] composed of [an] address". Each call
      # to the macro adds a description of how the value objects are created from the attributes of
      # the entity object (when the entity is initialized either as a new object or from finding an
      # existing object) and how it can be turned back into attributes (when the entity is saved to
      # the database).
      #
      #   class Customer < ActiveRecord::Base
      #     composed_of :balance, class_name: "Money", mapping: %w(balance amount)
      #     composed_of :address, mapping: [ %w(address_street street), %w(address_city city) ]
      #   end
      #
      # The customer class now has the following methods to manipulate the value objects:
      # * <tt>Customer#balance, Customer#balance=(money)</tt>
      # * <tt>Customer#address, Customer#address=(address)</tt>
      #
      # These methods will operate with value objects like the ones described below:
      #
      #  class Money
      #    include Comparable
      #    attr_reader :amount, :currency
      #    EXCHANGE_RATES = { "USD_TO_DKK" => 6 }
      #
      #    def initialize(amount, currency = "USD")
      #      @amount, @currency = amount, currency
      #    end
      #
      #    def exchange_to(other_currency)
      #      exchanged_amount = (amount * EXCHANGE_RATES["#{currency}_TO_#{other_currency}"]).floor
      #      Money.new(exchanged_amount, other_currency)
      #    end
      #
      #    def ==(other_money)
      #      amount == other_money.amount && currency == other_money.currency
      #    end
      #
      #    def <=>(other_money)
      #      if currency == other_money.currency
      #        amount <=> other_money.amount
      #      else
      #        amount <=> other_money.exchange_to(currency).amount
      #      end
      #    end
      #  end
      #
      #  class Address
      #    attr_reader :street, :city
      #    def initialize(street, city)
      #      @street, @city = street, city
      #    end
      #
      #    def close_to?(other_address)
      #      city == other_address.city
      #    end
      #
      #    def ==(other_address)
      #      city == other_address.city && street == other_address.street
      #    end
      #  end
      #
      # Now it's possible to access attributes from the database through the value objects instead. If
      # you choose to name the composition the same as the attribute's name, it will be the only way to
      # access that attribute. That's the case with our +balance+ attribute. You interact with the value
      # objects just like you would with any other attribute:
      #
      #   customer.balance = Money.new(20)     # sets the Money value object and the attribute
      #   customer.balance                     # => Money value object
      #   customer.balance.exchange_to("DKK")  # => Money.new(120, "DKK")
      #   customer.balance > Money.new(10)     # => true
      #   customer.balance == Money.new(20)    # => true
      #   customer.balance < Money.new(5)      # => false
      #
      # Value objects can also be composed of multiple attributes, such as the case of Address. The order
      # of the mappings will determine the order of the parameters.
      #
      #   customer.address_street = "Hyancintvej"
      #   customer.address_city   = "Copenhagen"
      #   customer.address        # => Address.new("Hyancintvej", "Copenhagen")
      #
      #   customer.address = Address.new("May Street", "Chicago")
      #   customer.address_street # => "May Street"
      #   customer.address_city   # => "Chicago"
      #
      # == Writing value objects
      #
      # Value objects are immutable and interchangeable objects that represent a given value, such as
      # a Money object representing $5. Two Money objects both representing $5 should be equal (through
      # methods such as <tt>==</tt> and <tt><=></tt> from Comparable if ranking makes sense). This is
      # unlike entity objects where equality is determined by identity. An entity class such as Customer can
      # easily have two different objects that both have an address on Hyancintvej. Entity identity is
      # determined by object or relational unique identifiers (such as primary keys). Normal
      # ActiveRecord::Base classes are entity objects.
      #
      # It's also important to treat the value objects as immutable. Don't allow the Money object to have
      # its amount changed after creation. Create a new Money object with the new value instead. The
      # <tt>Money#exchange_to</tt> method is an example of this. It returns a new value object instead of changing
      # its own values. Active Record won't persist value objects that have been changed through means
      # other than the writer method.
      #
      # The immutable requirement is enforced by Active Record by freezing any object assigned as a value
      # object. Attempting to change it afterwards will result in a +RuntimeError+.
      #
      # Read more about value objects on http://c2.com/cgi/wiki?ValueObject and on the dangers of not
      # keeping value objects immutable on http://c2.com/cgi/wiki?ValueObjectsShouldBeImmutable
      #
      # == Custom constructors and converters
      #
      # By default value objects are initialized by calling the <tt>new</tt> constructor of the value
      # class passing each of the mapped attributes, in the order specified by the <tt>:mapping</tt>
      # option, as arguments. If the value class doesn't support this convention then #composed_of allows
      # a custom constructor to be specified.
      #
      # When a new value is assigned to the value object, the default assumption is that the new value
      # is an instance of the value class. Specifying a custom converter allows the new value to be automatically
      # converted to an instance of value class if necessary.
      #
      # For example, the +NetworkResource+ model has +network_address+ and +cidr_range+ attributes that should be
      # aggregated using the +NetAddr::CIDR+ value class (https://www.rubydoc.info/gems/netaddr/1.5.0/NetAddr/CIDR).
      # The constructor for the value class is called +create+ and it expects a CIDR address string as a parameter.
      # New values can be assigned to the value object using either another +NetAddr::CIDR+ object, a string
      # or an array. The <tt>:constructor</tt> and <tt>:converter</tt> options can be used to meet
      # these requirements:
      #
      #   class NetworkResource < ActiveRecord::Base
      #     composed_of :cidr,
      #                 class_name: 'NetAddr::CIDR',
      #                 mapping: [ %w(network_address network), %w(cidr_range bits) ],
      #                 allow_nil: true,
      #                 constructor: Proc.new { |network_address, cidr_range| NetAddr::CIDR.create("#{network_address}/#{cidr_range}") },
      #                 converter: Proc.new { |value| NetAddr::CIDR.create(value.is_a?(Array) ? value.join('/') : value) }
      #   end
      #
      #   # This calls the :constructor
      #   network_resource = NetworkResource.new(network_address: '192.168.0.1', cidr_range: 24)
      #
      #   # These assignments will both use the :converter
      #   network_resource.cidr = [ '192.168.2.1', 8 ]
      #   network_resource.cidr = '192.168.0.1/24'
      #
      #   # This assignment won't use the :converter as the value is already an instance of the value class
      #   network_resource.cidr = NetAddr::CIDR.create('192.168.2.1/8')
      #
      #   # Saving and then reloading will use the :constructor on reload
      #   network_resource.save
      #   network_resource.reload
      #
      # == Finding records by a value object
      #
      # Once a #composed_of relationship is specified for a model, records can be loaded from the database
      # by specifying an instance of the value object in the conditions hash. The following example
      # finds all customers with +address_street+ equal to "May Street" and +address_city+ equal to "Chicago":
      #
      #   Customer.where(address: Address.new("May Street", "Chicago"))
      #
      module ClassMethods
        # Adds reader and writer methods for manipulating a value object:
        # <tt>composed_of :address</tt> adds <tt>address</tt> and <tt>address=(new_address)</tt> methods.
        #
        # Options are:
        # * <tt>:class_name</tt> - Specifies the class name of the association. Use it only if that name
        #   can't be inferred from the part id. So <tt>composed_of :address</tt> will by default be linked
        #   to the Address class, but if the real class name is +CompanyAddress+, you'll have to specify it
        #   with this option.
        # * <tt>:mapping</tt> - Specifies the mapping of entity attributes to attributes of the value
        #   object. Each mapping is represented as an array where the first item is the name of the
        #   entity attribute and the second item is the name of the attribute in the value object. The
        #   order in which mappings are defined determines the order in which attributes are sent to the
        #   value class constructor.
        # * <tt>:allow_nil</tt> - Specifies that the value object will not be instantiated when all mapped
        #   attributes are +nil+. Setting the value object to +nil+ has the effect of writing +nil+ to all
        #   mapped attributes.
        #   This defaults to +false+.
        # * <tt>:constructor</tt> - A symbol specifying the name of the constructor method or a Proc that
        #   is called to initialize the value object. The constructor is passed all of the mapped attributes,
        #   in the order that they are defined in the <tt>:mapping option</tt>, as arguments and uses them
        #   to instantiate a <tt>:class_name</tt> object.
        #   The default is <tt>:new</tt>.
        # * <tt>:converter</tt> - A symbol specifying the name of a class method of <tt>:class_name</tt>
        #   or a Proc that is called when a new value is assigned to the value object. The converter is
        #   passed the single value that is used in the assignment and is only called if the new value is
        #   not an instance of <tt>:class_name</tt>. If <tt>:allow_nil</tt> is set to true, the converter
        #   can return +nil+ to skip the assignment.
        #
        # Option examples:
        #   composed_of :temperature, mapping: %w(reading celsius)
        #   composed_of :balance, class_name: "Money", mapping: %w(balance amount)
        #   composed_of :address, mapping: [ %w(address_street street), %w(address_city city) ]
        #   composed_of :gps_location
        #   composed_of :gps_location, allow_nil: true
        #   composed_of :ip_address,
        #               class_name: 'IPAddr',
        #               mapping: %w(ip to_i),
        #               constructor: Proc.new { |ip| IPAddr.new(ip, Socket::AF_INET) },
        #               converter: Proc.new { |ip| ip.is_a?(Integer) ? IPAddr.new(ip, Socket::AF_INET) : IPAddr.new(ip.to_s) }
        #
        def composed_of(part_id, options = {})
          options.assert_valid_keys(:class_name, :mapping, :allow_nil, :constructor, :converter)

          unless self < Aggregations
            include Aggregations
          end

          name        = part_id.id2name
          class_name  = options[:class_name]  || name.camelize
          mapping     = options[:mapping]     || [ name, name ]
          mapping     = [ mapping ] unless mapping.first.is_a?(Array)
          allow_nil   = options[:allow_nil]   || false
          constructor = options[:constructor] || :new
          converter   = options[:converter]

          reader_method(name, class_name, mapping, allow_nil, constructor)
          writer_method(name, class_name, mapping, allow_nil, converter)

          reflection = ActiveRecord::Reflection.create(:composed_of, part_id, nil, options, self)
          Reflection.add_aggregate_reflection self, part_id, reflection
        end

        private
          def reader_method(name, class_name, mapping, allow_nil, constructor)
            define_method(name) do
              if @aggregation_cache[name].nil? && (!allow_nil || mapping.any? { |key, _| !read_attribute(key).nil? })
                attrs = mapping.collect { |key, _| read_attribute(key) }
                object = constructor.respond_to?(:call) ?
                  constructor.call(*attrs) :
                  class_name.constantize.send(constructor, *attrs)
                @aggregation_cache[name] = object
              end
              @aggregation_cache[name]
            end
          end

          def writer_method(name, class_name, mapping, allow_nil, converter)
            define_method("#{name}=") do |part|
              klass = class_name.constantize

              unless part.is_a?(klass) || converter.nil? || part.nil?
                part = converter.respond_to?(:call) ? converter.call(part) : klass.send(converter, part)
              end

              hash_from_multiparameter_assignment = part.is_a?(Hash) &&
                part.keys.all?(Integer)
              if hash_from_multiparameter_assignment
                raise ArgumentError unless part.size == part.each_key.max
                part = klass.new(*part.sort.map(&:last))
              end

              if part.nil? && allow_nil
                mapping.each { |key, _| write_attribute(key, nil) }
                @aggregation_cache[name] = nil
              else
                mapping.each { |key, value| write_attribute(key, part.send(value)) }
                @aggregation_cache[name] = part.freeze
              end
            end
          end
      end
  end
end

alias_predication.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module AliasPredication
    def as(other)
      Nodes::As.new self, Nodes::SqlLiteral.new(other)
    end
  end
end

alias_tracker.rb

# frozen_string_literal: true

require "active_support/core_ext/string/conversions"

module ActiveRecord
  module Associations
    # Keeps track of table aliases for ActiveRecord::Associations::JoinDependency
    class AliasTracker # :nodoc:
      def self.create(connection, initial_table, joins, aliases = nil)
        if joins.empty?
          aliases ||= Hash.new(0)
        elsif aliases
          default_proc = aliases.default_proc || proc { 0 }
          aliases.default_proc = proc { |h, k|
            h[k] = initial_count_for(connection, k, joins) + default_proc.call(h, k)
          }
        else
          aliases = Hash.new { |h, k|
            h[k] = initial_count_for(connection, k, joins)
          }
        end
        aliases[initial_table] = 1
        new(connection, aliases)
      end

      def self.initial_count_for(connection, name, table_joins)
        quoted_name = nil

        counts = table_joins.map do |join|
          if join.is_a?(Arel::Nodes::StringJoin)
            # quoted_name should be case ignored as some database adapters (Oracle) return quoted name in uppercase
            quoted_name ||= connection.quote_table_name(name)

            # Table names + table aliases
            join.left.scan(
              /JOIN(?:\s+\w+)?\s+(?:\S+\s+)?(?:#{quoted_name}|#{name})\sON/i
            ).size
          elsif join.is_a?(Arel::Nodes::Join)
            join.left.name == name ? 1 : 0
          else
            raise ArgumentError, "joins list should be initialized by list of Arel::Nodes::Join"
          end
        end

        counts.sum
      end

      # table_joins is an array of arel joins which might conflict with the aliases we assign here
      def initialize(connection, aliases)
        @aliases    = aliases
        @connection = connection
      end

      def aliased_table_for(arel_table, table_name = nil)
        table_name ||= arel_table.name

        if aliases[table_name] == 0
          # If it's zero, we can have our table_name
          aliases[table_name] = 1
          arel_table = arel_table.alias(table_name) if arel_table.name != table_name
        else
          # Otherwise, we need to use an alias
          aliased_name = @connection.table_alias_for(yield)

          # Update the count
          count = aliases[aliased_name] += 1

          aliased_name = "#{truncate(aliased_name)}_#{count}" if count > 1

          arel_table = arel_table.alias(aliased_name)
        end

        arel_table
      end

      attr_reader :aliases

      private
        def truncate(name)
          name.slice(0, @connection.table_alias_length - 2)
        end
    end
  end
end

and.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class And < Arel::Nodes::NodeExpression
      attr_reader :children

      def initialize(children)
        super()
        @children = children
      end

      def left
        children.first
      end

      def right
        children[1]
      end

      def hash
        children.hash
      end

      def eql?(other)
        self.class == other.class &&
          self.children == other.children
      end
      alias :== :eql?
    end
  end
end

application_record_generator.rb

# frozen_string_literal: true

require "rails/generators/active_record"

module ActiveRecord
  module Generators # :nodoc:
    class ApplicationRecordGenerator < ::Rails::Generators::Base # :nodoc:
      source_root File.expand_path("templates", __dir__)

      # FIXME: Change this file to a symlink once RubyGems 2.5.0 is required.
      def create_application_record
        template "application_record.rb", application_record_file_name
      end

      private
        def application_record_file_name
          @application_record_file_name ||=
            if namespaced?
              "app/models/#{namespaced_path}/application_record.rb"
            else
              "app/models/application_record.rb"
            end
        end
    end
  end
end

arel.rb

# frozen_string_literal: true

require "arel/errors"

require "arel/crud"
require "arel/factory_methods"

require "arel/expressions"
require "arel/predications"
require "arel/filter_predications"
require "arel/window_predications"
require "arel/math"
require "arel/alias_predication"
require "arel/order_predications"
require "arel/table"
require "arel/attributes/attribute"

require "arel/visitors"
require "arel/collectors/sql_string"

require "arel/tree_manager"
require "arel/insert_manager"
require "arel/select_manager"
require "arel/update_manager"
require "arel/delete_manager"
require "arel/nodes"

module Arel
  VERSION = "10.0.0"

  # Wrap a known-safe SQL string for passing to query methods, e.g.
  #
  #   Post.order(Arel.sql("REPLACE(title, 'misc', 'zzzz') asc")).pluck(:id)
  #
  # Great caution should be taken to avoid SQL injection vulnerabilities.
  # This method should not be used with unsafe values such as request
  # parameters or model attributes.
  def self.sql(raw_sql)
    Arel::Nodes::SqlLiteral.new raw_sql
  end

  def self.star # :nodoc:
    sql "*"
  end

  def self.arel_node?(value) # :nodoc:
    value.is_a?(Arel::Nodes::Node) || value.is_a?(Arel::Attribute) || value.is_a?(Arel::Nodes::SqlLiteral)
  end

  def self.fetch_attribute(value, &block) # :nodoc:
    unless String === value
      value.fetch_attribute(&block)
    end
  end
end

array.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Array < Type::Value # :nodoc:
          include ActiveModel::Type::Helpers::Mutable

          Data = Struct.new(:encoder, :values) # :nodoc:

          attr_reader :subtype, :delimiter
          delegate :type, :user_input_in_time_zone, :limit, :precision, :scale, to: :subtype

          def initialize(subtype, delimiter = ",")
            @subtype = subtype
            @delimiter = delimiter

            @pg_encoder = PG::TextEncoder::Array.new name: "#{type}[]", delimiter: delimiter
            @pg_decoder = PG::TextDecoder::Array.new name: "#{type}[]", delimiter: delimiter
          end

          def deserialize(value)
            case value
            when ::String
              type_cast_array(@pg_decoder.decode(value), :deserialize)
            when Data
              type_cast_array(value.values, :deserialize)
            else
              super
            end
          end

          def cast(value)
            if value.is_a?(::String)
              value = begin
                @pg_decoder.decode(value)
              rescue TypeError
                # malformed array string is treated as [], will raise in PG 2.0 gem
                # this keeps a consistent implementation
                []
              end
            end
            type_cast_array(value, :cast)
          end

          def serialize(value)
            if value.is_a?(::Array)
              casted_values = type_cast_array(value, :serialize)
              Data.new(@pg_encoder, casted_values)
            else
              super
            end
          end

          def ==(other)
            other.is_a?(Array) &&
              subtype == other.subtype &&
              delimiter == other.delimiter
          end

          def type_cast_for_schema(value)
            return super unless value.is_a?(::Array)
            "[" + value.map { |v| subtype.type_cast_for_schema(v) }.join(", ") + "]"
          end

          def map(value, &block)
            value.map(&block)
          end

          def changed_in_place?(raw_old_value, new_value)
            deserialize(raw_old_value) != new_value
          end

          def force_equality?(value)
            value.is_a?(::Array)
          end

          private
            def type_cast_array(value, method)
              if value.is_a?(::Array)
                value.map { |item| type_cast_array(item, method) }
              else
                @subtype.public_send(method, value)
              end
            end
        end
      end
    end
  end
end

array_handler.rb

# frozen_string_literal: true

require "active_support/core_ext/array/extract"

module ActiveRecord
  class PredicateBuilder
    class ArrayHandler # :nodoc:
      def initialize(predicate_builder)
        @predicate_builder = predicate_builder
      end

      def call(attribute, value)
        return attribute.in([]) if value.empty?

        values = value.map { |x| x.is_a?(Base) ? x.id : x }
        nils = values.extract!(&:nil?)
        ranges = values.extract! { |v| v.is_a?(Range) }

        values_predicate =
          case values.length
          when 0 then NullPredicate
          when 1 then predicate_builder.build(attribute, values.first)
          else Arel::Nodes::HomogeneousIn.new(values, attribute, :in)
          end

        unless nils.empty?
          values_predicate = values_predicate.or(attribute.eq(nil))
        end

        if ranges.empty?
          values_predicate
        else
          array_predicates = ranges.map! { |range| predicate_builder.build(attribute, range) }
          array_predicates.inject(values_predicate, &:or)
        end
      end

      private
        attr_reader :predicate_builder

        module NullPredicate # :nodoc:
          def self.or(other)
            other
          end
        end
    end
  end
end

ascending.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Ascending < Ordering
      def reverse
        Descending.new(expr)
      end

      def direction
        :asc
      end

      def ascending?
        true
      end

      def descending?
        false
      end
    end
  end
end

associated.rb

# frozen_string_literal: true

module ActiveRecord
  module Validations
    class AssociatedValidator < ActiveModel::EachValidator # :nodoc:
      def validate_each(record, attribute, value)
        if Array(value).reject { |r| valid_object?(r) }.any?
          record.errors.add(attribute, :invalid, **options.merge(value: value))
        end
      end

      private
        def valid_object?(record)
          (record.respond_to?(:marked_for_destruction?) && record.marked_for_destruction?) || record.valid?
        end
    end

    module ClassMethods
      # Validates whether the associated object or objects are all valid.
      # Works with any kind of association.
      #
      #   class Book < ActiveRecord::Base
      #     has_many :pages
      #     belongs_to :library
      #
      #     validates_associated :pages, :library
      #   end
      #
      # WARNING: This validation must not be used on both ends of an association.
      # Doing so will lead to a circular dependency and cause infinite recursion.
      #
      # NOTE: This validation will not fail if the association hasn't been
      # assigned. If you want to ensure that the association is both present and
      # guaranteed to be valid, you also need to use
      # {validates_presence_of}[rdoc-ref:Validations::ClassMethods#validates_presence_of].
      #
      # Configuration options:
      #
      # * <tt>:message</tt> - A custom error message (default is: "is invalid").
      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
      #   Runs in all validation contexts by default +nil+. You can pass a symbol
      #   or an array of symbols. (e.g. <tt>on: :create</tt> or
      #   <tt>on: :custom_validation_context</tt> or
      #   <tt>on: [:create, :custom_validation_context]</tt>)
      # * <tt>:if</tt> - Specifies a method, proc, or string to call to determine
      #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
      #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
      #   proc or string should return or evaluate to a +true+ or +false+ value.
      # * <tt>:unless</tt> - Specifies a method, proc, or string to call to
      #   determine if the validation should not occur (e.g. <tt>unless: :skip_validation</tt>,
      #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
      #   method, proc, or string should return or evaluate to a +true+ or +false+
      #   value.
      def validates_associated(*attr_names)
        validates_with AssociatedValidator, _merge_attributes(attr_names)
      end
    end
  end
end

association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class Preloader
      class Association # :nodoc:
        class LoaderQuery
          attr_reader :scope, :association_key_name

          def initialize(scope, association_key_name)
            @scope = scope
            @association_key_name = association_key_name
          end

          def eql?(other)
            association_key_name == other.association_key_name &&
              scope.table_name == other.scope.table_name &&
              scope.values_for_queries == other.scope.values_for_queries
          end

          def hash
            [association_key_name, scope.table_name, scope.values_for_queries].hash
          end

          def records_for(loaders)
            LoaderRecords.new(loaders, self).records
          end

          def load_records_in_batch(loaders)
            raw_records = records_for(loaders)

            loaders.each do |loader|
              loader.load_records(raw_records)
              loader.run
            end
          end

          def load_records_for_keys(keys, &block)
            scope.where(association_key_name => keys).load(&block)
          end
        end

        class LoaderRecords
          def initialize(loaders, loader_query)
            @loader_query = loader_query
            @loaders = loaders
            @keys_to_load = Set.new
            @already_loaded_records_by_key = {}

            populate_keys_to_load_and_already_loaded_records
          end

          def records
            load_records + already_loaded_records
          end

          private
            attr_reader :loader_query, :loaders, :keys_to_load, :already_loaded_records_by_key

            def populate_keys_to_load_and_already_loaded_records
              loaders.each do |loader|
                loader.owners_by_key.each do |key, owners|
                  if loaded_owner = owners.find { |owner| loader.loaded?(owner) }
                    already_loaded_records_by_key[key] = loader.target_for(loaded_owner)
                  else
                    keys_to_load << key
                  end
                end
              end

              @keys_to_load.subtract(already_loaded_records_by_key.keys)
            end

            def load_records
              loader_query.load_records_for_keys(keys_to_load) do |record|
                loaders.each { |l| l.set_inverse(record) }
              end
            end

            def already_loaded_records
              already_loaded_records_by_key.values.flatten
            end
        end

        attr_reader :klass

        def initialize(klass, owners, reflection, preload_scope, reflection_scope, associate_by_default)
          @klass         = klass
          @owners        = owners.uniq(&:__id__)
          @reflection    = reflection
          @preload_scope = preload_scope
          @reflection_scope = reflection_scope
          @associate     = associate_by_default || !preload_scope || preload_scope.empty_scope?
          @model         = owners.first && owners.first.class
          @run = false
        end

        def table_name
          @klass.table_name
        end

        def future_classes
          if run?
            []
          else
            [@klass]
          end
        end

        def runnable_loaders
          [self]
        end

        def run?
          @run
        end

        def run
          return self if run?
          @run = true

          records = records_by_owner

          owners.each do |owner|
            associate_records_to_owner(owner, records[owner] || [])
          end if @associate

          self
        end

        def records_by_owner
          load_records unless defined?(@records_by_owner)

          @records_by_owner
        end

        def preloaded_records
          load_records unless defined?(@preloaded_records)

          @preloaded_records
        end

        # The name of the key on the associated records
        def association_key_name
          reflection.join_primary_key(klass)
        end

        def loader_query
          LoaderQuery.new(scope, association_key_name)
        end

        def owners_by_key
          @owners_by_key ||= owners.each_with_object({}) do |owner, result|
            key = convert_key(owner[owner_key_name])
            (result[key] ||= []) << owner if key
          end
        end

        def loaded?(owner)
          owner.association(reflection.name).loaded?
        end

        def target_for(owner)
          Array.wrap(owner.association(reflection.name).target)
        end

        def scope
          @scope ||= build_scope
        end

        def set_inverse(record)
          if owners = owners_by_key[convert_key(record[association_key_name])]
            # Processing only the first owner
            # because the record is modified but not an owner
            association = owners.first.association(reflection.name)
            association.set_inverse_instance(record)
          end
        end

        def load_records(raw_records = nil)
          # owners can be duplicated when a relation has a collection association join
          # #compare_by_identity makes such owners different hash keys
          @records_by_owner = {}.compare_by_identity
          raw_records ||= loader_query.records_for([self])

          @preloaded_records = raw_records.select do |record|
            assignments = false

            owners_by_key[convert_key(record[association_key_name])]&.each do |owner|
              entries = (@records_by_owner[owner] ||= [])

              if reflection.collection? || entries.empty?
                entries << record
                assignments = true
              end
            end

            assignments
          end
        end

        def associate_records_from_unscoped(unscoped_records)
          return if unscoped_records.nil? || unscoped_records.empty?
          return if !reflection_scope.empty_scope?
          return if preload_scope && !preload_scope.empty_scope?
          return if reflection.collection?

          unscoped_records.select { |r| r[association_key_name].present? }.each do |record|
            owners = owners_by_key[convert_key(record[association_key_name])]
            owners&.each_with_index do |owner, i|
              association = owner.association(reflection.name)
              association.target = record

              if i == 0 # Set inverse on first owner
                association.set_inverse_instance(record)
              end
            end
          end
        end

        private
          attr_reader :owners, :reflection, :preload_scope, :model

          # The name of the key on the model which declares the association
          def owner_key_name
            reflection.join_foreign_key
          end

          def associate_records_to_owner(owner, records)
            return if loaded?(owner)

            association = owner.association(reflection.name)

            if reflection.collection?
              association.target = records
            else
              association.target = records.first
            end
          end

          def key_conversion_required?
            unless defined?(@key_conversion_required)
              @key_conversion_required = (association_key_type != owner_key_type)
            end

            @key_conversion_required
          end

          def convert_key(key)
            if key_conversion_required?
              key.to_s
            else
              key
            end
          end

          def association_key_type
            @klass.type_for_attribute(association_key_name).type
          end

          def owner_key_type
            @model.type_for_attribute(owner_key_name).type
          end

          def reflection_scope
            @reflection_scope ||= reflection.join_scopes(klass.arel_table, klass.predicate_builder, klass).inject(klass.unscoped, &:merge!)
          end

          def build_scope
            scope = klass.scope_for_association

            if reflection.type && !reflection.through_reflection?
              scope.where!(reflection.type => model.polymorphic_name)
            end

            scope.merge!(reflection_scope) unless reflection_scope.empty_scope?

            if preload_scope && !preload_scope.empty_scope?
              scope.merge!(preload_scope)
            end

            cascade_strict_loading(scope)
          end

          def cascade_strict_loading(scope)
            preload_scope&.strict_loading_value ? scope.strict_loading : scope
          end
      end
    end
  end
end

association_query_value.rb

# frozen_string_literal: true

module ActiveRecord
  class PredicateBuilder
    class AssociationQueryValue # :nodoc:
      def initialize(associated_table, value)
        @associated_table = associated_table
        @value = value
      end

      def queries
        [ associated_table.join_foreign_key => ids ]
      end

      private
        attr_reader :associated_table, :value

        def ids
          case value
          when Relation
            value.select_values.empty? ? value.select(primary_key) : value
          when Array
            value.map { |v| convert_to_id(v) }
          else
            convert_to_id(value)
          end
        end

        def primary_key
          associated_table.join_primary_key
        end

        def convert_to_id(value)
          if value.respond_to?(primary_key)
            value.public_send(primary_key)
          else
            value
          end
        end
    end
  end
end

association_relation.rb

# frozen_string_literal: true

module ActiveRecord
  class AssociationRelation < Relation # :nodoc:
    def initialize(klass, association, **)
      super(klass)
      @association = association
    end

    def proxy_association
      @association
    end

    def ==(other)
      other == records
    end

    %w(insert insert_all insert! insert_all! upsert upsert_all).each do |method|
      class_eval <<~RUBY
        def #{method}(attributes, **kwargs)
          if @association.reflection.through_reflection?
            raise ArgumentError, "Bulk insert or upsert is currently not supported for has_many through association"
          end

          scoping { klass.#{method}(attributes, **kwargs) }
        end
      RUBY
    end

    private
      def _new(attributes, &block)
        @association.build(attributes, &block)
      end

      def _create(attributes, &block)
        @association.create(attributes, &block)
      end

      def _create!(attributes, &block)
        @association.create!(attributes, &block)
      end

      def exec_queries
        super do |record|
          @association.set_inverse_instance_from_queries(record)
          yield record if block_given?
        end
      end
  end
end

association_scope.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class AssociationScope # :nodoc:
      def self.scope(association)
        INSTANCE.scope(association)
      end

      def self.create(&block)
        block ||= lambda { |val| val }
        new(block)
      end

      def initialize(value_transformation)
        @value_transformation = value_transformation
      end

      INSTANCE = create

      def scope(association)
        klass = association.klass
        reflection = association.reflection
        scope = klass.unscoped
        owner = association.owner
        chain = get_chain(reflection, association, scope.alias_tracker)

        scope.extending! reflection.extensions
        scope = add_constraints(scope, owner, chain)
        scope.limit!(1) unless reflection.collection?
        scope
      end

      def self.get_bind_values(owner, chain)
        binds = []
        last_reflection = chain.last

        binds << last_reflection.join_id_for(owner)
        if last_reflection.type
          binds << owner.class.polymorphic_name
        end

        chain.each_cons(2).each do |reflection, next_reflection|
          if reflection.type
            binds << next_reflection.klass.polymorphic_name
          end
        end
        binds
      end

      private
        attr_reader :value_transformation

        def join(table, constraint)
          Arel::Nodes::LeadingJoin.new(table, Arel::Nodes::On.new(constraint))
        end

        def last_chain_scope(scope, reflection, owner)
          primary_key = reflection.join_primary_key
          foreign_key = reflection.join_foreign_key

          table = reflection.aliased_table
          value = transform_value(owner[foreign_key])
          scope = apply_scope(scope, table, primary_key, value)

          if reflection.type
            polymorphic_type = transform_value(owner.class.polymorphic_name)
            scope = apply_scope(scope, table, reflection.type, polymorphic_type)
          end

          scope
        end

        def transform_value(value)
          value_transformation.call(value)
        end

        def next_chain_scope(scope, reflection, next_reflection)
          primary_key = reflection.join_primary_key
          foreign_key = reflection.join_foreign_key

          table = reflection.aliased_table
          foreign_table = next_reflection.aliased_table
          constraint = table[primary_key].eq(foreign_table[foreign_key])

          if reflection.type
            value = transform_value(next_reflection.klass.polymorphic_name)
            scope = apply_scope(scope, table, reflection.type, value)
          end

          scope.joins!(join(foreign_table, constraint))
        end

        class ReflectionProxy < SimpleDelegator # :nodoc:
          attr_reader :aliased_table

          def initialize(reflection, aliased_table)
            super(reflection)
            @aliased_table = aliased_table
          end

          def all_includes; nil; end
        end

        def get_chain(reflection, association, tracker)
          name = reflection.name
          chain = [Reflection::RuntimeReflection.new(reflection, association)]
          reflection.chain.drop(1).each do |refl|
            aliased_table = tracker.aliased_table_for(refl.klass.arel_table) do
              refl.alias_candidate(name)
            end
            chain << ReflectionProxy.new(refl, aliased_table)
          end
          chain
        end

        def add_constraints(scope, owner, chain)
          scope = last_chain_scope(scope, chain.last, owner)

          chain.each_cons(2) do |reflection, next_reflection|
            scope = next_chain_scope(scope, reflection, next_reflection)
          end

          chain_head = chain.first
          chain.reverse_each do |reflection|
            reflection.constraints.each do |scope_chain_item|
              item = eval_scope(reflection, scope_chain_item, owner)

              if scope_chain_item == chain_head.scope
                scope.merge! item.except(:where, :includes, :unscope, :order)
              elsif !item.references_values.empty?
                scope.merge! item.only(:joins, :left_outer_joins)

                associations = item.eager_load_values | item.includes_values

                unless associations.empty?
                  scope.joins! item.construct_join_dependency(associations, Arel::Nodes::OuterJoin)
                end
              end

              reflection.all_includes do
                scope.includes_values |= item.includes_values
              end

              scope.unscope!(*item.unscope_values)
              scope.where_clause += item.where_clause
              scope.order_values = item.order_values | scope.order_values
            end
          end

          scope
        end

        def apply_scope(scope, table, key, value)
          if scope.table == table
            scope.where!(key => value)
          else
            scope.where!(table.name => { key => value })
          end
        end

        def eval_scope(reflection, scope, owner)
          relation = reflection.build_scope(reflection.aliased_table)
          relation.instance_exec(owner, &scope) || relation
        end
    end
  end
end

associations.rb

# frozen_string_literal: true

module ActiveRecord
  class AssociationNotFoundError < ConfigurationError # :nodoc:
    attr_reader :record, :association_name

    def initialize(record = nil, association_name = nil)
      @record           = record
      @association_name = association_name
      if record && association_name
        super("Association named '#{association_name}' was not found on #{record.class.name}; perhaps you misspelled it?")
      else
        super("Association was not found.")
      end
    end

    if defined?(DidYouMean::Correctable) && defined?(DidYouMean::SpellChecker)
      include DidYouMean::Correctable

      def corrections
        if record && association_name
          @corrections ||= begin
            maybe_these = record.class.reflections.keys
            DidYouMean::SpellChecker.new(dictionary: maybe_these).correct(association_name)
          end
        else
          []
        end
      end
    end
  end

  class InverseOfAssociationNotFoundError < ActiveRecordError # :nodoc:
    attr_reader :reflection, :associated_class

    def initialize(reflection = nil, associated_class = nil)
      if reflection
        @reflection = reflection
        @associated_class = associated_class.nil? ? reflection.klass : associated_class
        super("Could not find the inverse association for #{reflection.name} (#{reflection.options[:inverse_of].inspect} in #{associated_class.nil? ? reflection.class_name : associated_class.name})")
      else
        super("Could not find the inverse association.")
      end
    end

    if defined?(DidYouMean::Correctable) && defined?(DidYouMean::SpellChecker)
      include DidYouMean::Correctable

      def corrections
        if reflection && associated_class
          @corrections ||= begin
            maybe_these = associated_class.reflections.keys
            DidYouMean::SpellChecker.new(dictionary: maybe_these).correct(reflection.options[:inverse_of].to_s)
          end
        else
          []
        end
      end
    end
  end

  class InverseOfAssociationRecursiveError < ActiveRecordError # :nodoc:
    attr_reader :reflection
    def initialize(reflection = nil)
      if reflection
        @reflection = reflection
        super("Inverse association #{reflection.name} (#{reflection.options[:inverse_of].inspect} in #{reflection.class_name}) is recursive.")
      else
        super("Inverse association is recursive.")
      end
    end
  end

  class HasManyThroughAssociationNotFoundError < ActiveRecordError # :nodoc:
    attr_reader :owner_class, :reflection

    def initialize(owner_class = nil, reflection = nil)
      if owner_class && reflection
        @owner_class = owner_class
        @reflection = reflection
        super("Could not find the association #{reflection.options[:through].inspect} in model #{owner_class.name}")
      else
        super("Could not find the association.")
      end
    end

    if defined?(DidYouMean::Correctable) && defined?(DidYouMean::SpellChecker)
      include DidYouMean::Correctable

      def corrections
        if owner_class && reflection
          @corrections ||= begin
            maybe_these = owner_class.reflections.keys
            maybe_these -= [reflection.name.to_s] # remove failing reflection
            DidYouMean::SpellChecker.new(dictionary: maybe_these).correct(reflection.options[:through].to_s)
          end
        else
          []
        end
      end
    end
  end

  class HasManyThroughAssociationPolymorphicSourceError < ActiveRecordError # :nodoc:
    def initialize(owner_class_name = nil, reflection = nil, source_reflection = nil)
      if owner_class_name && reflection && source_reflection
        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' on the polymorphic object '#{source_reflection.class_name}##{source_reflection.name}' without 'source_type'. Try adding 'source_type: \"#{reflection.name.to_s.classify}\"' to 'has_many :through' definition.")
      else
        super("Cannot have a has_many :through association.")
      end
    end
  end

  class HasManyThroughAssociationPolymorphicThroughError < ActiveRecordError # :nodoc:
    def initialize(owner_class_name = nil, reflection = nil)
      if owner_class_name && reflection
        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' which goes through the polymorphic association '#{owner_class_name}##{reflection.through_reflection.name}'.")
      else
        super("Cannot have a has_many :through association.")
      end
    end
  end

  class HasManyThroughAssociationPointlessSourceTypeError < ActiveRecordError # :nodoc:
    def initialize(owner_class_name = nil, reflection = nil, source_reflection = nil)
      if owner_class_name && reflection && source_reflection
        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic. Try removing :source_type on your association.")
      else
        super("Cannot have a has_many :through association.")
      end
    end
  end

  class HasOneThroughCantAssociateThroughCollection < ActiveRecordError # :nodoc:
    def initialize(owner_class_name = nil, reflection = nil, through_reflection = nil)
      if owner_class_name && reflection && through_reflection
        super("Cannot have a has_one :through association '#{owner_class_name}##{reflection.name}' where the :through association '#{owner_class_name}##{through_reflection.name}' is a collection. Specify a has_one or belongs_to association in the :through option instead.")
      else
        super("Cannot have a has_one :through association.")
      end
    end
  end

  class HasOneAssociationPolymorphicThroughError < ActiveRecordError # :nodoc:
    def initialize(owner_class_name = nil, reflection = nil)
      if owner_class_name && reflection
        super("Cannot have a has_one :through association '#{owner_class_name}##{reflection.name}' which goes through the polymorphic association '#{owner_class_name}##{reflection.through_reflection.name}'.")
      else
        super("Cannot have a has_one :through association.")
      end
    end
  end

  class HasManyThroughSourceAssociationNotFoundError < ActiveRecordError # :nodoc:
    def initialize(reflection = nil)
      if reflection
        through_reflection      = reflection.through_reflection
        source_reflection_names = reflection.source_reflection_names
        source_associations     = reflection.through_reflection.klass._reflections.keys
        super("Could not find the source association(s) #{source_reflection_names.collect(&:inspect).to_sentence(two_words_connector: ' or ', last_word_connector: ', or ')} in model #{through_reflection.klass}. Try 'has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}, :source => <name>'. Is it one of #{source_associations.to_sentence(two_words_connector: ' or ', last_word_connector: ', or ')}?")
      else
        super("Could not find the source association(s).")
      end
    end
  end

  class HasManyThroughOrderError < ActiveRecordError # :nodoc:
    def initialize(owner_class_name = nil, reflection = nil, through_reflection = nil)
      if owner_class_name && reflection && through_reflection
        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' which goes through '#{owner_class_name}##{through_reflection.name}' before the through association is defined.")
      else
        super("Cannot have a has_many :through association before the through association is defined.")
      end
    end
  end

  class ThroughCantAssociateThroughHasOneOrManyReflection < ActiveRecordError # :nodoc:
    def initialize(owner = nil, reflection = nil)
      if owner && reflection
        super("Cannot modify association '#{owner.class.name}##{reflection.name}' because the source reflection class '#{reflection.source_reflection.class_name}' is associated to '#{reflection.through_reflection.class_name}' via :#{reflection.source_reflection.macro}.")
      else
        super("Cannot modify association.")
      end
    end
  end

  class AmbiguousSourceReflectionForThroughAssociation < ActiveRecordError # :nodoc:
    def initialize(klass, macro, association_name, options, possible_sources)
      example_options = options.dup
      example_options[:source] = possible_sources.first

      super("Ambiguous source reflection for through association. Please " \
            "specify a :source directive on your declaration like:\n" \
            "\n" \
            "  class #{klass} < ActiveRecord::Base\n" \
            "    #{macro} :#{association_name}, #{example_options}\n" \
            "  end"
           )
    end
  end

  class HasManyThroughCantAssociateThroughHasOneOrManyReflection < ThroughCantAssociateThroughHasOneOrManyReflection # :nodoc:
  end

  class HasOneThroughCantAssociateThroughHasOneOrManyReflection < ThroughCantAssociateThroughHasOneOrManyReflection # :nodoc:
  end

  class ThroughNestedAssociationsAreReadonly < ActiveRecordError # :nodoc:
    def initialize(owner = nil, reflection = nil)
      if owner && reflection
        super("Cannot modify association '#{owner.class.name}##{reflection.name}' because it goes through more than one other association.")
      else
        super("Through nested associations are read-only.")
      end
    end
  end

  class HasManyThroughNestedAssociationsAreReadonly < ThroughNestedAssociationsAreReadonly # :nodoc:
  end

  class HasOneThroughNestedAssociationsAreReadonly < ThroughNestedAssociationsAreReadonly # :nodoc:
  end

  # This error is raised when trying to eager load a polymorphic association using a JOIN.
  # Eager loading polymorphic associations is only possible with
  # {ActiveRecord::Relation#preload}[rdoc-ref:QueryMethods#preload].
  class EagerLoadPolymorphicError < ActiveRecordError
    def initialize(reflection = nil)
      if reflection
        super("Cannot eagerly load the polymorphic association #{reflection.name.inspect}")
      else
        super("Eager load polymorphic error.")
      end
    end
  end

  # This error is raised when trying to destroy a parent instance in N:1 or 1:1 associations
  # (has_many, has_one) when there is at least 1 child associated instance.
  # ex: if @project.tasks.size > 0, DeleteRestrictionError will be raised when trying to destroy @project
  class DeleteRestrictionError < ActiveRecordError # :nodoc:
    def initialize(name = nil)
      if name
        super("Cannot delete record because of dependent #{name}")
      else
        super("Delete restriction error.")
      end
    end
  end

  # See ActiveRecord::Associations::ClassMethods for documentation.
  module Associations # :nodoc:
    extend ActiveSupport::Autoload
    extend ActiveSupport::Concern

    # These classes will be loaded when associations are created.
    # So there is no need to eager load them.
    autoload :Association
    autoload :SingularAssociation
    autoload :CollectionAssociation
    autoload :ForeignAssociation
    autoload :CollectionProxy
    autoload :ThroughAssociation

    module Builder # :nodoc:
      autoload :Association,           "active_record/associations/builder/association"
      autoload :SingularAssociation,   "active_record/associations/builder/singular_association"
      autoload :CollectionAssociation, "active_record/associations/builder/collection_association"

      autoload :BelongsTo,           "active_record/associations/builder/belongs_to"
      autoload :HasOne,              "active_record/associations/builder/has_one"
      autoload :HasMany,             "active_record/associations/builder/has_many"
      autoload :HasAndBelongsToMany, "active_record/associations/builder/has_and_belongs_to_many"
    end

    eager_autoload do
      autoload :BelongsToAssociation
      autoload :BelongsToPolymorphicAssociation
      autoload :HasManyAssociation
      autoload :HasManyThroughAssociation
      autoload :HasOneAssociation
      autoload :HasOneThroughAssociation

      autoload :Preloader
      autoload :JoinDependency
      autoload :AssociationScope
      autoload :DisableJoinsAssociationScope
      autoload :AliasTracker
    end

    def self.eager_load!
      super
      Preloader.eager_load!
      JoinDependency.eager_load!
    end

    # Returns the association instance for the given name, instantiating it if it doesn't already exist
    def association(name) # :nodoc:
      association = association_instance_get(name)

      if association.nil?
        unless reflection = self.class._reflect_on_association(name)
          raise AssociationNotFoundError.new(self, name)
        end
        association = reflection.association_class.new(self, reflection)
        association_instance_set(name, association)
      end

      association
    end

    def association_cached?(name) # :nodoc:
      @association_cache.key?(name)
    end

    def initialize_dup(*) # :nodoc:
      @association_cache = {}
      super
    end

    private
      def init_internals
        @association_cache = {}
        super
      end

      # Returns the specified association instance if it exists, +nil+ otherwise.
      def association_instance_get(name)
        @association_cache[name]
      end

      # Set the specified association instance.
      def association_instance_set(name, association)
        @association_cache[name] = association
      end

      # \Associations are a set of macro-like class methods for tying objects together through
      # foreign keys. They express relationships like "Project has one Project Manager"
      # or "Project belongs to a Portfolio". Each macro adds a number of methods to the
      # class which are specialized according to the collection or association symbol and the
      # options hash. It works much the same way as Ruby's own <tt>attr*</tt>
      # methods.
      #
      #   class Project < ActiveRecord::Base
      #     belongs_to              :portfolio
      #     has_one                 :project_manager
      #     has_many                :milestones
      #     has_and_belongs_to_many :categories
      #   end
      #
      # The project class now has the following methods (and more) to ease the traversal and
      # manipulation of its relationships:
      # * <tt>Project#portfolio</tt>, <tt>Project#portfolio=(portfolio)</tt>, <tt>Project#reload_portfolio</tt>
      # * <tt>Project#project_manager</tt>, <tt>Project#project_manager=(project_manager)</tt>, <tt>Project#reload_project_manager</tt>
      # * <tt>Project#milestones.empty?</tt>, <tt>Project#milestones.size</tt>, <tt>Project#milestones</tt>, <tt>Project#milestones<<(milestone)</tt>,
      #   <tt>Project#milestones.delete(milestone)</tt>, <tt>Project#milestones.destroy(milestone)</tt>, <tt>Project#milestones.find(milestone_id)</tt>,
      #   <tt>Project#milestones.build</tt>, <tt>Project#milestones.create</tt>
      # * <tt>Project#categories.empty?</tt>, <tt>Project#categories.size</tt>, <tt>Project#categories</tt>, <tt>Project#categories<<(category1)</tt>,
      #   <tt>Project#categories.delete(category1)</tt>, <tt>Project#categories.destroy(category1)</tt>
      #
      # === A word of warning
      #
      # Don't create associations that have the same name as {instance methods}[rdoc-ref:ActiveRecord::Core] of
      # <tt>ActiveRecord::Base</tt>. Since the association adds a method with that name to
      # its model, using an association with the same name as one provided by <tt>ActiveRecord::Base</tt> will override the method inherited through <tt>ActiveRecord::Base</tt> and will break things.
      # For instance, +attributes+ and +connection+ would be bad choices for association names, because those names already exist in the list of <tt>ActiveRecord::Base</tt> instance methods.
      #
      # == Auto-generated methods
      # See also Instance Public methods below for more details.
      #
      # === Singular associations (one-to-one)
      #                                     |            |  belongs_to  |
      #   generated methods                 | belongs_to | :polymorphic | has_one
      #   ----------------------------------+------------+--------------+---------
      #   other                             |     X      |      X       |    X
      #   other=(other)                     |     X      |      X       |    X
      #   build_other(attributes={})        |     X      |              |    X
      #   create_other(attributes={})       |     X      |              |    X
      #   create_other!(attributes={})      |     X      |              |    X
      #   reload_other                      |     X      |      X       |    X
      #   other_changed?                    |     X      |      X       |
      #   other_previously_changed?         |     X      |      X       |
      #
      # === Collection associations (one-to-many / many-to-many)
      #                                     |       |          | has_many
      #   generated methods                 | habtm | has_many | :through
      #   ----------------------------------+-------+----------+----------
      #   others                            |   X   |    X     |    X
      #   others=(other,other,...)          |   X   |    X     |    X
      #   other_ids                         |   X   |    X     |    X
      #   other_ids=(id,id,...)             |   X   |    X     |    X
      #   others<<                          |   X   |    X     |    X
      #   others.push                       |   X   |    X     |    X
      #   others.concat                     |   X   |    X     |    X
      #   others.build(attributes={})       |   X   |    X     |    X
      #   others.create(attributes={})      |   X   |    X     |    X
      #   others.create!(attributes={})     |   X   |    X     |    X
      #   others.size                       |   X   |    X     |    X
      #   others.length                     |   X   |    X     |    X
      #   others.count                      |   X   |    X     |    X
      #   others.sum(*args)                 |   X   |    X     |    X
      #   others.empty?                     |   X   |    X     |    X
      #   others.clear                      |   X   |    X     |    X
      #   others.delete(other,other,...)    |   X   |    X     |    X
      #   others.delete_all                 |   X   |    X     |    X
      #   others.destroy(other,other,...)   |   X   |    X     |    X
      #   others.destroy_all                |   X   |    X     |    X
      #   others.find(*args)                |   X   |    X     |    X
      #   others.exists?                    |   X   |    X     |    X
      #   others.distinct                   |   X   |    X     |    X
      #   others.reset                      |   X   |    X     |    X
      #   others.reload                     |   X   |    X     |    X
      #
      # === Overriding generated methods
      #
      # Association methods are generated in a module included into the model
      # class, making overrides easy. The original generated method can thus be
      # called with +super+:
      #
      #   class Car < ActiveRecord::Base
      #     belongs_to :owner
      #     belongs_to :old_owner
      #
      #     def owner=(new_owner)
      #       self.old_owner = self.owner
      #       super
      #     end
      #   end
      #
      # The association methods module is included immediately after the
      # generated attributes methods module, meaning an association will
      # override the methods for an attribute with the same name.
      #
      # == Cardinality and associations
      #
      # Active Record associations can be used to describe one-to-one, one-to-many, and many-to-many
      # relationships between models. Each model uses an association to describe its role in
      # the relation. The #belongs_to association is always used in the model that has
      # the foreign key.
      #
      # === One-to-one
      #
      # Use #has_one in the base, and #belongs_to in the associated model.
      #
      #   class Employee < ActiveRecord::Base
      #     has_one :office
      #   end
      #   class Office < ActiveRecord::Base
      #     belongs_to :employee    # foreign key - employee_id
      #   end
      #
      # === One-to-many
      #
      # Use #has_many in the base, and #belongs_to in the associated model.
      #
      #   class Manager < ActiveRecord::Base
      #     has_many :employees
      #   end
      #   class Employee < ActiveRecord::Base
      #     belongs_to :manager     # foreign key - manager_id
      #   end
      #
      # === Many-to-many
      #
      # There are two ways to build a many-to-many relationship.
      #
      # The first way uses a #has_many association with the <tt>:through</tt> option and a join model, so
      # there are two stages of associations.
      #
      #   class Assignment < ActiveRecord::Base
      #     belongs_to :programmer  # foreign key - programmer_id
      #     belongs_to :project     # foreign key - project_id
      #   end
      #   class Programmer < ActiveRecord::Base
      #     has_many :assignments
      #     has_many :projects, through: :assignments
      #   end
      #   class Project < ActiveRecord::Base
      #     has_many :assignments
      #     has_many :programmers, through: :assignments
      #   end
      #
      # For the second way, use #has_and_belongs_to_many in both models. This requires a join table
      # that has no corresponding model or primary key.
      #
      #   class Programmer < ActiveRecord::Base
      #     has_and_belongs_to_many :projects       # foreign keys in the join table
      #   end
      #   class Project < ActiveRecord::Base
      #     has_and_belongs_to_many :programmers    # foreign keys in the join table
      #   end
      #
      # Choosing which way to build a many-to-many relationship is not always simple.
      # If you need to work with the relationship model as its own entity,
      # use #has_many <tt>:through</tt>. Use #has_and_belongs_to_many when working with legacy schemas or when
      # you never work directly with the relationship itself.
      #
      # == Is it a #belongs_to or #has_one association?
      #
      # Both express a 1-1 relationship. The difference is mostly where to place the foreign
      # key, which goes on the table for the class declaring the #belongs_to relationship.
      #
      #   class User < ActiveRecord::Base
      #     # I reference an account.
      #     belongs_to :account
      #   end
      #
      #   class Account < ActiveRecord::Base
      #     # One user references me.
      #     has_one :user
      #   end
      #
      # The tables for these classes could look something like:
      #
      #   CREATE TABLE users (
      #     id bigint NOT NULL auto_increment,
      #     account_id bigint default NULL,
      #     name varchar default NULL,
      #     PRIMARY KEY  (id)
      #   )
      #
      #   CREATE TABLE accounts (
      #     id bigint NOT NULL auto_increment,
      #     name varchar default NULL,
      #     PRIMARY KEY  (id)
      #   )
      #
      # == Unsaved objects and associations
      #
      # You can manipulate objects and associations before they are saved to the database, but
      # there is some special behavior you should be aware of, mostly involving the saving of
      # associated objects.
      #
      # You can set the <tt>:autosave</tt> option on a #has_one, #belongs_to,
      # #has_many, or #has_and_belongs_to_many association. Setting it
      # to +true+ will _always_ save the members, whereas setting it to +false+ will
      # _never_ save the members. More details about <tt>:autosave</tt> option is available at
      # AutosaveAssociation.
      #
      # === One-to-one associations
      #
      # * Assigning an object to a #has_one association automatically saves that object and
      #   the object being replaced (if there is one), in order to update their foreign
      #   keys - except if the parent object is unsaved (<tt>new_record? == true</tt>).
      # * If either of these saves fail (due to one of the objects being invalid), an
      #   ActiveRecord::RecordNotSaved exception is raised and the assignment is
      #   cancelled.
      # * If you wish to assign an object to a #has_one association without saving it,
      #   use the <tt>#build_association</tt> method (documented below). The object being
      #   replaced will still be saved to update its foreign key.
      # * Assigning an object to a #belongs_to association does not save the object, since
      #   the foreign key field belongs on the parent. It does not save the parent either.
      #
      # === Collections
      #
      # * Adding an object to a collection (#has_many or #has_and_belongs_to_many) automatically
      #   saves that object, except if the parent object (the owner of the collection) is not yet
      #   stored in the database.
      # * If saving any of the objects being added to a collection (via <tt>push</tt> or similar)
      #   fails, then <tt>push</tt> returns +false+.
      # * If saving fails while replacing the collection (via <tt>association=</tt>), an
      #   ActiveRecord::RecordNotSaved exception is raised and the assignment is
      #   cancelled.
      # * You can add an object to a collection without automatically saving it by using the
      #   <tt>collection.build</tt> method (documented below).
      # * All unsaved (<tt>new_record? == true</tt>) members of the collection are automatically
      #   saved when the parent is saved.
      #
      # == Customizing the query
      #
      # \Associations are built from <tt>Relation</tt> objects, and you can use the Relation syntax
      # to customize them. For example, to add a condition:
      #
      #   class Blog < ActiveRecord::Base
      #     has_many :published_posts, -> { where(published: true) }, class_name: 'Post'
      #   end
      #
      # Inside the <tt>-> { ... }</tt> block you can use all of the usual Relation methods.
      #
      # === Accessing the owner object
      #
      # Sometimes it is useful to have access to the owner object when building the query. The owner
      # is passed as a parameter to the block. For example, the following association would find all
      # events that occur on the user's birthday:
      #
      #   class User < ActiveRecord::Base
      #     has_many :birthday_events, ->(user) { where(starts_on: user.birthday) }, class_name: 'Event'
      #   end
      #
      # Note: Joining, eager loading, and preloading of these associations is not possible.
      # These operations happen before instance creation and the scope will be called with a +nil+ argument.
      #
      # == Association callbacks
      #
      # Similar to the normal callbacks that hook into the life cycle of an Active Record object,
      # you can also define callbacks that get triggered when you add an object to or remove an
      # object from an association collection.
      #
      #   class Firm < ActiveRecord::Base
      #     has_many :clients,
      #              dependent: :destroy,
      #              after_add: :congratulate_client,
      #              after_remove: :log_after_remove
      #
      #     def congratulate_client(record)
      #       # ...
      #     end
      #
      #     def log_after_remove(record)
      #       # ...
      #     end
      #
      # It's possible to stack callbacks by passing them as an array. Example:
      #
      #   class Firm < ActiveRecord::Base
      #     has_many :clients,
      #              dependent: :destroy,
      #              after_add: [:congratulate_client, -> (firm, record) { firm.log << "after_adding#{record.id}" }],
      #              after_remove: :log_after_remove
      #   end
      #
      # Possible callbacks are: +before_add+, +after_add+, +before_remove+, and +after_remove+.
      #
      # If any of the +before_add+ callbacks throw an exception, the object will not be
      # added to the collection.
      #
      # Similarly, if any of the +before_remove+ callbacks throw an exception, the object
      # will not be removed from the collection.
      #
      # Note: To trigger remove callbacks, you must use +destroy+ / +destroy_all+ methods. For example:
      #
      #   * <tt>firm.clients.destroy(client)</tt>
      #   * <tt>firm.clients.destroy(*clients)</tt>
      #   * <tt>firm.clients.destroy_all</tt>
      #
      # +delete+ / +delete_all+ methods like the following do *not* trigger remove callbacks:
      #
      #   * <tt>firm.clients.delete(client)</tt>
      #   * <tt>firm.clients.delete(*clients)</tt>
      #   * <tt>firm.clients.delete_all</tt>
      #
      # == Association extensions
      #
      # The proxy objects that control the access to associations can be extended through anonymous
      # modules. This is especially beneficial for adding new finders, creators, and other
      # factory-type methods that are only used as part of this association.
      #
      #   class Account < ActiveRecord::Base
      #     has_many :people do
      #       def find_or_create_by_name(name)
      #         first_name, last_name = name.split(" ", 2)
      #         find_or_create_by(first_name: first_name, last_name: last_name)
      #       end
      #     end
      #   end
      #
      #   person = Account.first.people.find_or_create_by_name("David Heinemeier Hansson")
      #   person.first_name # => "David"
      #   person.last_name  # => "Heinemeier Hansson"
      #
      # If you need to share the same extensions between many associations, you can use a named
      # extension module.
      #
      #   module FindOrCreateByNameExtension
      #     def find_or_create_by_name(name)
      #       first_name, last_name = name.split(" ", 2)
      #       find_or_create_by(first_name: first_name, last_name: last_name)
      #     end
      #   end
      #
      #   class Account < ActiveRecord::Base
      #     has_many :people, -> { extending FindOrCreateByNameExtension }
      #   end
      #
      #   class Company < ActiveRecord::Base
      #     has_many :people, -> { extending FindOrCreateByNameExtension }
      #   end
      #
      # Some extensions can only be made to work with knowledge of the association's internals.
      # Extensions can access relevant state using the following methods (where +items+ is the
      # name of the association):
      #
      # * <tt>record.association(:items).owner</tt> - Returns the object the association is part of.
      # * <tt>record.association(:items).reflection</tt> - Returns the reflection object that describes the association.
      # * <tt>record.association(:items).target</tt> - Returns the associated object for #belongs_to and #has_one, or
      #   the collection of associated objects for #has_many and #has_and_belongs_to_many.
      #
      # However, inside the actual extension code, you will not have access to the <tt>record</tt> as
      # above. In this case, you can access <tt>proxy_association</tt>. For example,
      # <tt>record.association(:items)</tt> and <tt>record.items.proxy_association</tt> will return
      # the same object, allowing you to make calls like <tt>proxy_association.owner</tt> inside
      # association extensions.
      #
      # == Association Join Models
      #
      # Has Many associations can be configured with the <tt>:through</tt> option to use an
      # explicit join model to retrieve the data. This operates similarly to a
      # #has_and_belongs_to_many association. The advantage is that you're able to add validations,
      # callbacks, and extra attributes on the join model. Consider the following schema:
      #
      #   class Author < ActiveRecord::Base
      #     has_many :authorships
      #     has_many :books, through: :authorships
      #   end
      #
      #   class Authorship < ActiveRecord::Base
      #     belongs_to :author
      #     belongs_to :book
      #   end
      #
      #   @author = Author.first
      #   @author.authorships.collect { |a| a.book } # selects all books that the author's authorships belong to
      #   @author.books                              # selects all books by using the Authorship join model
      #
      # You can also go through a #has_many association on the join model:
      #
      #   class Firm < ActiveRecord::Base
      #     has_many   :clients
      #     has_many   :invoices, through: :clients
      #   end
      #
      #   class Client < ActiveRecord::Base
      #     belongs_to :firm
      #     has_many   :invoices
      #   end
      #
      #   class Invoice < ActiveRecord::Base
      #     belongs_to :client
      #   end
      #
      #   @firm = Firm.first
      #   @firm.clients.flat_map { |c| c.invoices } # select all invoices for all clients of the firm
      #   @firm.invoices                            # selects all invoices by going through the Client join model
      #
      # Similarly you can go through a #has_one association on the join model:
      #
      #   class Group < ActiveRecord::Base
      #     has_many   :users
      #     has_many   :avatars, through: :users
      #   end
      #
      #   class User < ActiveRecord::Base
      #     belongs_to :group
      #     has_one    :avatar
      #   end
      #
      #   class Avatar < ActiveRecord::Base
      #     belongs_to :user
      #   end
      #
      #   @group = Group.first
      #   @group.users.collect { |u| u.avatar }.compact # select all avatars for all users in the group
      #   @group.avatars                                # selects all avatars by going through the User join model.
      #
      # An important caveat with going through #has_one or #has_many associations on the
      # join model is that these associations are *read-only*. For example, the following
      # would not work following the previous example:
      #
      #   @group.avatars << Avatar.new   # this would work if User belonged_to Avatar rather than the other way around
      #   @group.avatars.delete(@group.avatars.last)  # so would this
      #
      # == Setting Inverses
      #
      # If you are using a #belongs_to on the join model, it is a good idea to set the
      # <tt>:inverse_of</tt> option on the #belongs_to, which will mean that the following example
      # works correctly (where <tt>tags</tt> is a #has_many <tt>:through</tt> association):
      #
      #   @post = Post.first
      #   @tag = @post.tags.build name: "ruby"
      #   @tag.save
      #
      # The last line ought to save the through record (a <tt>Tagging</tt>). This will only work if the
      # <tt>:inverse_of</tt> is set:
      #
      #   class Tagging < ActiveRecord::Base
      #     belongs_to :post
      #     belongs_to :tag, inverse_of: :taggings
      #   end
      #
      # If you do not set the <tt>:inverse_of</tt> record, the association will
      # do its best to match itself up with the correct inverse. Automatic
      # inverse detection only works on #has_many, #has_one, and
      # #belongs_to associations.
      #
      # <tt>:foreign_key</tt> and <tt>:through</tt> options on the associations
      # will also prevent the association's inverse from being found automatically,
      # as will a custom scopes in some cases. See further details in the
      # {Active Record Associations guide}[https://guides.rubyonrails.org/association_basics.html#bi-directional-associations].
      #
      # The automatic guessing of the inverse association uses a heuristic based
      # on the name of the class, so it may not work for all associations,
      # especially the ones with non-standard names.
      #
      # You can turn off the automatic detection of inverse associations by setting
      # the <tt>:inverse_of</tt> option to <tt>false</tt> like so:
      #
      #   class Tagging < ActiveRecord::Base
      #     belongs_to :tag, inverse_of: false
      #   end
      #
      # == Nested \Associations
      #
      # You can actually specify *any* association with the <tt>:through</tt> option, including an
      # association which has a <tt>:through</tt> option itself. For example:
      #
      #   class Author < ActiveRecord::Base
      #     has_many :posts
      #     has_many :comments, through: :posts
      #     has_many :commenters, through: :comments
      #   end
      #
      #   class Post < ActiveRecord::Base
      #     has_many :comments
      #   end
      #
      #   class Comment < ActiveRecord::Base
      #     belongs_to :commenter
      #   end
      #
      #   @author = Author.first
      #   @author.commenters # => People who commented on posts written by the author
      #
      # An equivalent way of setting up this association this would be:
      #
      #   class Author < ActiveRecord::Base
      #     has_many :posts
      #     has_many :commenters, through: :posts
      #   end
      #
      #   class Post < ActiveRecord::Base
      #     has_many :comments
      #     has_many :commenters, through: :comments
      #   end
      #
      #   class Comment < ActiveRecord::Base
      #     belongs_to :commenter
      #   end
      #
      # When using a nested association, you will not be able to modify the association because there
      # is not enough information to know what modification to make. For example, if you tried to
      # add a <tt>Commenter</tt> in the example above, there would be no way to tell how to set up the
      # intermediate <tt>Post</tt> and <tt>Comment</tt> objects.
      #
      # == Polymorphic \Associations
      #
      # Polymorphic associations on models are not restricted on what types of models they
      # can be associated with. Rather, they specify an interface that a #has_many association
      # must adhere to.
      #
      #   class Asset < ActiveRecord::Base
      #     belongs_to :attachable, polymorphic: true
      #   end
      #
      #   class Post < ActiveRecord::Base
      #     has_many :assets, as: :attachable         # The :as option specifies the polymorphic interface to use.
      #   end
      #
      #   @asset.attachable = @post
      #
      # This works by using a type column in addition to a foreign key to specify the associated
      # record. In the Asset example, you'd need an +attachable_id+ integer column and an
      # +attachable_type+ string column.
      #
      # Using polymorphic associations in combination with single table inheritance (STI) is
      # a little tricky. In order for the associations to work as expected, ensure that you
      # store the base model for the STI models in the type column of the polymorphic
      # association. To continue with the asset example above, suppose there are guest posts
      # and member posts that use the posts table for STI. In this case, there must be a +type+
      # column in the posts table.
      #
      # Note: The <tt>attachable_type=</tt> method is being called when assigning an +attachable+.
      # The +class_name+ of the +attachable+ is passed as a String.
      #
      #   class Asset < ActiveRecord::Base
      #     belongs_to :attachable, polymorphic: true
      #
      #     def attachable_type=(class_name)
      #        super(class_name.constantize.base_class.to_s)
      #     end
      #   end
      #
      #   class Post < ActiveRecord::Base
      #     # because we store "Post" in attachable_type now dependent: :destroy will work
      #     has_many :assets, as: :attachable, dependent: :destroy
      #   end
      #
      #   class GuestPost < Post
      #   end
      #
      #   class MemberPost < Post
      #   end
      #
      # == Caching
      #
      # All of the methods are built on a simple caching principle that will keep the result
      # of the last query around unless specifically instructed not to. The cache is even
      # shared across methods to make it even cheaper to use the macro-added methods without
      # worrying too much about performance at the first go.
      #
      #   project.milestones             # fetches milestones from the database
      #   project.milestones.size        # uses the milestone cache
      #   project.milestones.empty?      # uses the milestone cache
      #   project.milestones.reload.size # fetches milestones from the database
      #   project.milestones             # uses the milestone cache
      #
      # == Eager loading of associations
      #
      # Eager loading is a way to find objects of a certain class and a number of named associations.
      # It is one of the easiest ways to prevent the dreaded N+1 problem in which fetching 100
      # posts that each need to display their author triggers 101 database queries. Through the
      # use of eager loading, the number of queries will be reduced from 101 to 2.
      #
      #   class Post < ActiveRecord::Base
      #     belongs_to :author
      #     has_many   :comments
      #   end
      #
      # Consider the following loop using the class above:
      #
      #   Post.all.each do |post|
      #     puts "Post:            " + post.title
      #     puts "Written by:      " + post.author.name
      #     puts "Last comment on: " + post.comments.first.created_on
      #   end
      #
      # To iterate over these one hundred posts, we'll generate 201 database queries. Let's
      # first just optimize it for retrieving the author:
      #
      #   Post.includes(:author).each do |post|
      #
      # This references the name of the #belongs_to association that also used the <tt>:author</tt>
      # symbol. After loading the posts, +find+ will collect the +author_id+ from each one and load
      # all of the referenced authors with one query. Doing so will cut down the number of queries
      # from 201 to 102.
      #
      # We can improve upon the situation further by referencing both associations in the finder with:
      #
      #   Post.includes(:author, :comments).each do |post|
      #
      # This will load all comments with a single query. This reduces the total number of queries
      # to 3. In general, the number of queries will be 1 plus the number of associations
      # named (except if some of the associations are polymorphic #belongs_to - see below).
      #
      # To include a deep hierarchy of associations, use a hash:
      #
      #   Post.includes(:author, { comments: { author: :gravatar } }).each do |post|
      #
      # The above code will load all the comments and all of their associated
      # authors and gravatars. You can mix and match any combination of symbols,
      # arrays, and hashes to retrieve the associations you want to load.
      #
      # All of this power shouldn't fool you into thinking that you can pull out huge amounts
      # of data with no performance penalty just because you've reduced the number of queries.
      # The database still needs to send all the data to Active Record and it still needs to
      # be processed. So it's no catch-all for performance problems, but it's a great way to
      # cut down on the number of queries in a situation as the one described above.
      #
      # Since only one table is loaded at a time, conditions or orders cannot reference tables
      # other than the main one. If this is the case, Active Record falls back to the previously
      # used <tt>LEFT OUTER JOIN</tt> based strategy. For example:
      #
      #   Post.includes([:author, :comments]).where(['comments.approved = ?', true])
      #
      # This will result in a single SQL query with joins along the lines of:
      # <tt>LEFT OUTER JOIN comments ON comments.post_id = posts.id</tt> and
      # <tt>LEFT OUTER JOIN authors ON authors.id = posts.author_id</tt>. Note that using conditions
      # like this can have unintended consequences.
      # In the above example, posts with no approved comments are not returned at all because
      # the conditions apply to the SQL statement as a whole and not just to the association.
      #
      # You must disambiguate column references for this fallback to happen, for example
      # <tt>order: "author.name DESC"</tt> will work but <tt>order: "name DESC"</tt> will not.
      #
      # If you want to load all posts (including posts with no approved comments), then write
      # your own <tt>LEFT OUTER JOIN</tt> query using <tt>ON</tt>:
      #
      #   Post.joins("LEFT OUTER JOIN comments ON comments.post_id = posts.id AND comments.approved = '1'")
      #
      # In this case, it is usually more natural to include an association which has conditions defined on it:
      #
      #   class Post < ActiveRecord::Base
      #     has_many :approved_comments, -> { where(approved: true) }, class_name: 'Comment'
      #   end
      #
      #   Post.includes(:approved_comments)
      #
      # This will load posts and eager load the +approved_comments+ association, which contains
      # only those comments that have been approved.
      #
      # If you eager load an association with a specified <tt>:limit</tt> option, it will be ignored,
      # returning all the associated objects:
      #
      #   class Picture < ActiveRecord::Base
      #     has_many :most_recent_comments, -> { order('id DESC').limit(10) }, class_name: 'Comment'
      #   end
      #
      #   Picture.includes(:most_recent_comments).first.most_recent_comments # => returns all associated comments.
      #
      # Eager loading is supported with polymorphic associations.
      #
      #   class Address < ActiveRecord::Base
      #     belongs_to :addressable, polymorphic: true
      #   end
      #
      # A call that tries to eager load the addressable model
      #
      #   Address.includes(:addressable)
      #
      # This will execute one query to load the addresses and load the addressables with one
      # query per addressable type.
      # For example, if all the addressables are either of class Person or Company, then a total
      # of 3 queries will be executed. The list of addressable types to load is determined on
      # the back of the addresses loaded. This is not supported if Active Record has to fallback
      # to the previous implementation of eager loading and will raise ActiveRecord::EagerLoadPolymorphicError.
      # The reason is that the parent model's type is a column value so its corresponding table
      # name cannot be put in the +FROM+/+JOIN+ clauses of that query.
      #
      # == Table Aliasing
      #
      # Active Record uses table aliasing in the case that a table is referenced multiple times
      # in a join. If a table is referenced only once, the standard table name is used. The
      # second time, the table is aliased as <tt>#{reflection_name}_#{parent_table_name}</tt>.
      # Indexes are appended for any more successive uses of the table name.
      #
      #   Post.joins(:comments)
      #   # => SELECT ... FROM posts INNER JOIN comments ON ...
      #   Post.joins(:special_comments) # STI
      #   # => SELECT ... FROM posts INNER JOIN comments ON ... AND comments.type = 'SpecialComment'
      #   Post.joins(:comments, :special_comments) # special_comments is the reflection name, posts is the parent table name
      #   # => SELECT ... FROM posts INNER JOIN comments ON ... INNER JOIN comments special_comments_posts
      #
      # Acts as tree example:
      #
      #   TreeMixin.joins(:children)
      #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
      #   TreeMixin.joins(children: :parent)
      #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
      #                               INNER JOIN parents_mixins ...
      #   TreeMixin.joins(children: {parent: :children})
      #   # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
      #                               INNER JOIN parents_mixins ...
      #                               INNER JOIN mixins childrens_mixins_2
      #
      # Has and Belongs to Many join tables use the same idea, but add a <tt>_join</tt> suffix:
      #
      #   Post.joins(:categories)
      #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
      #   Post.joins(categories: :posts)
      #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
      #                              INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
      #   Post.joins(categories: {posts: :categories})
      #   # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
      #                              INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
      #                              INNER JOIN categories_posts categories_posts_join INNER JOIN categories categories_posts_2
      #
      # If you wish to specify your own custom joins using ActiveRecord::QueryMethods#joins method, those table
      # names will take precedence over the eager associations:
      #
      #   Post.joins(:comments).joins("inner join comments ...")
      #   # => SELECT ... FROM posts INNER JOIN comments_posts ON ... INNER JOIN comments ...
      #   Post.joins(:comments, :special_comments).joins("inner join comments ...")
      #   # => SELECT ... FROM posts INNER JOIN comments comments_posts ON ...
      #                              INNER JOIN comments special_comments_posts ...
      #                              INNER JOIN comments ...
      #
      # Table aliases are automatically truncated according to the maximum length of table identifiers
      # according to the specific database.
      #
      # == Modules
      #
      # By default, associations will look for objects within the current module scope. Consider:
      #
      #   module MyApplication
      #     module Business
      #       class Firm < ActiveRecord::Base
      #         has_many :clients
      #       end
      #
      #       class Client < ActiveRecord::Base; end
      #     end
      #   end
      #
      # When <tt>Firm#clients</tt> is called, it will in turn call
      # <tt>MyApplication::Business::Client.find_all_by_firm_id(firm.id)</tt>.
      # If you want to associate with a class in another module scope, this can be done by
      # specifying the complete class name.
      #
      #   module MyApplication
      #     module Business
      #       class Firm < ActiveRecord::Base; end
      #     end
      #
      #     module Billing
      #       class Account < ActiveRecord::Base
      #         belongs_to :firm, class_name: "MyApplication::Business::Firm"
      #       end
      #     end
      #   end
      #
      # == Bi-directional associations
      #
      # When you specify an association, there is usually an association on the associated model
      # that specifies the same relationship in reverse. For example, with the following models:
      #
      #    class Dungeon < ActiveRecord::Base
      #      has_many :traps
      #      has_one :evil_wizard
      #    end
      #
      #    class Trap < ActiveRecord::Base
      #      belongs_to :dungeon
      #    end
      #
      #    class EvilWizard < ActiveRecord::Base
      #      belongs_to :dungeon
      #    end
      #
      # The +traps+ association on +Dungeon+ and the +dungeon+ association on +Trap+ are
      # the inverse of each other, and the inverse of the +dungeon+ association on +EvilWizard+
      # is the +evil_wizard+ association on +Dungeon+ (and vice-versa). By default,
      # Active Record can guess the inverse of the association based on the name
      # of the class. The result is the following:
      #
      #    d = Dungeon.first
      #    t = d.traps.first
      #    d.object_id == t.dungeon.object_id # => true
      #
      # The +Dungeon+ instances +d+ and <tt>t.dungeon</tt> in the above example refer to
      # the same in-memory instance since the association matches the name of the class.
      # The result would be the same if we added +:inverse_of+ to our model definitions:
      #
      #    class Dungeon < ActiveRecord::Base
      #      has_many :traps, inverse_of: :dungeon
      #      has_one :evil_wizard, inverse_of: :dungeon
      #    end
      #
      #    class Trap < ActiveRecord::Base
      #      belongs_to :dungeon, inverse_of: :traps
      #    end
      #
      #    class EvilWizard < ActiveRecord::Base
      #      belongs_to :dungeon, inverse_of: :evil_wizard
      #    end
      #
      # For more information, see the documentation for the +:inverse_of+ option and the
      # {Active Record Associations guide}[https://guides.rubyonrails.org/association_basics.html#bi-directional-associations].
      #
      # == Deleting from associations
      #
      # === Dependent associations
      #
      # #has_many, #has_one, and #belongs_to associations support the <tt>:dependent</tt> option.
      # This allows you to specify that associated records should be deleted when the owner is
      # deleted.
      #
      # For example:
      #
      #     class Author
      #       has_many :posts, dependent: :destroy
      #     end
      #     Author.find(1).destroy # => Will destroy all of the author's posts, too
      #
      # The <tt>:dependent</tt> option can have different values which specify how the deletion
      # is done. For more information, see the documentation for this option on the different
      # specific association types. When no option is given, the behavior is to do nothing
      # with the associated records when destroying a record.
      #
      # Note that <tt>:dependent</tt> is implemented using Rails' callback
      # system, which works by processing callbacks in order. Therefore, other
      # callbacks declared either before or after the <tt>:dependent</tt> option
      # can affect what it does.
      #
      # Note that <tt>:dependent</tt> option is ignored for #has_one <tt>:through</tt> associations.
      #
      # === Delete or destroy?
      #
      # #has_many and #has_and_belongs_to_many associations have the methods <tt>destroy</tt>,
      # <tt>delete</tt>, <tt>destroy_all</tt> and <tt>delete_all</tt>.
      #
      # For #has_and_belongs_to_many, <tt>delete</tt> and <tt>destroy</tt> are the same: they
      # cause the records in the join table to be removed.
      #
      # For #has_many, <tt>destroy</tt> and <tt>destroy_all</tt> will always call the <tt>destroy</tt> method of the
      # record(s) being removed so that callbacks are run. However <tt>delete</tt> and <tt>delete_all</tt> will either
      # do the deletion according to the strategy specified by the <tt>:dependent</tt> option, or
      # if no <tt>:dependent</tt> option is given, then it will follow the default strategy.
      # The default strategy is to do nothing (leave the foreign keys with the parent ids set), except for
      # #has_many <tt>:through</tt>, where the default strategy is <tt>delete_all</tt> (delete
      # the join records, without running their callbacks).
      #
      # There is also a <tt>clear</tt> method which is the same as <tt>delete_all</tt>, except that
      # it returns the association rather than the records which have been deleted.
      #
      # === What gets deleted?
      #
      # There is a potential pitfall here: #has_and_belongs_to_many and #has_many <tt>:through</tt>
      # associations have records in join tables, as well as the associated records. So when we
      # call one of these deletion methods, what exactly should be deleted?
      #
      # The answer is that it is assumed that deletion on an association is about removing the
      # <i>link</i> between the owner and the associated object(s), rather than necessarily the
      # associated objects themselves. So with #has_and_belongs_to_many and #has_many
      # <tt>:through</tt>, the join records will be deleted, but the associated records won't.
      #
      # This makes sense if you think about it: if you were to call <tt>post.tags.delete(Tag.find_by(name: 'food'))</tt>
      # you would want the 'food' tag to be unlinked from the post, rather than for the tag itself
      # to be removed from the database.
      #
      # However, there are examples where this strategy doesn't make sense. For example, suppose
      # a person has many projects, and each project has many tasks. If we deleted one of a person's
      # tasks, we would probably not want the project to be deleted. In this scenario, the delete method
      # won't actually work: it can only be used if the association on the join model is a
      # #belongs_to. In other situations you are expected to perform operations directly on
      # either the associated records or the <tt>:through</tt> association.
      #
      # With a regular #has_many there is no distinction between the "associated records"
      # and the "link", so there is only one choice for what gets deleted.
      #
      # With #has_and_belongs_to_many and #has_many <tt>:through</tt>, if you want to delete the
      # associated records themselves, you can always do something along the lines of
      # <tt>person.tasks.each(&:destroy)</tt>.
      #
      # == Type safety with ActiveRecord::AssociationTypeMismatch
      #
      # If you attempt to assign an object to an association that doesn't match the inferred
      # or specified <tt>:class_name</tt>, you'll get an ActiveRecord::AssociationTypeMismatch.
      #
      # == Options
      #
      # All of the association macros can be specialized through options. This makes cases
      # more complex than the simple and guessable ones possible.
      module ClassMethods
        # Specifies a one-to-many association. The following methods for retrieval and query of
        # collections of associated objects will be added:
        #
        # +collection+ is a placeholder for the symbol passed as the +name+ argument, so
        # <tt>has_many :clients</tt> would add among others <tt>clients.empty?</tt>.
        #
        # [collection]
        #   Returns a Relation of all the associated objects.
        #   An empty Relation is returned if none are found.
        # [collection<<(object, ...)]
        #   Adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
        #   Note that this operation instantly fires update SQL without waiting for the save or update call on the
        #   parent object, unless the parent object is a new record.
        #   This will also run validations and callbacks of associated object(s).
        # [collection.delete(object, ...)]
        #   Removes one or more objects from the collection by setting their foreign keys to +NULL+.
        #   Objects will be in addition destroyed if they're associated with <tt>dependent: :destroy</tt>,
        #   and deleted if they're associated with <tt>dependent: :delete_all</tt>.
        #
        #   If the <tt>:through</tt> option is used, then the join records are deleted (rather than
        #   nullified) by default, but you can specify <tt>dependent: :destroy</tt> or
        #   <tt>dependent: :nullify</tt> to override this.
        # [collection.destroy(object, ...)]
        #   Removes one or more objects from the collection by running <tt>destroy</tt> on
        #   each record, regardless of any dependent option, ensuring callbacks are run.
        #
        #   If the <tt>:through</tt> option is used, then the join records are destroyed
        #   instead, not the objects themselves.
        # [collection=objects]
        #   Replaces the collections content by deleting and adding objects as appropriate. If the <tt>:through</tt>
        #   option is true callbacks in the join models are triggered except destroy callbacks, since deletion is
        #   direct by default. You can specify <tt>dependent: :destroy</tt> or
        #   <tt>dependent: :nullify</tt> to override this.
        # [collection_singular_ids]
        #   Returns an array of the associated objects' ids
        # [collection_singular_ids=ids]
        #   Replace the collection with the objects identified by the primary keys in +ids+. This
        #   method loads the models and calls <tt>collection=</tt>. See above.
        # [collection.clear]
        #   Removes every object from the collection. This destroys the associated objects if they
        #   are associated with <tt>dependent: :destroy</tt>, deletes them directly from the
        #   database if <tt>dependent: :delete_all</tt>, otherwise sets their foreign keys to +NULL+.
        #   If the <tt>:through</tt> option is true no destroy callbacks are invoked on the join models.
        #   Join models are directly deleted.
        # [collection.empty?]
        #   Returns +true+ if there are no associated objects.
        # [collection.size]
        #   Returns the number of associated objects.
        # [collection.find(...)]
        #   Finds an associated object according to the same rules as ActiveRecord::FinderMethods#find.
        # [collection.exists?(...)]
        #   Checks whether an associated object with the given conditions exists.
        #   Uses the same rules as ActiveRecord::FinderMethods#exists?.
        # [collection.build(attributes = {}, ...)]
        #   Returns one or more new objects of the collection type that have been instantiated
        #   with +attributes+ and linked to this object through a foreign key, but have not yet
        #   been saved.
        # [collection.create(attributes = {})]
        #   Returns a new object of the collection type that has been instantiated
        #   with +attributes+, linked to this object through a foreign key, and that has already
        #   been saved (if it passed the validation). *Note*: This only works if the base model
        #   already exists in the DB, not if it is a new (unsaved) record!
        # [collection.create!(attributes = {})]
        #   Does the same as <tt>collection.create</tt>, but raises ActiveRecord::RecordInvalid
        #   if the record is invalid.
        # [collection.reload]
        #   Returns a Relation of all of the associated objects, forcing a database read.
        #   An empty Relation is returned if none are found.
        #
        # === Example
        #
        # A <tt>Firm</tt> class declares <tt>has_many :clients</tt>, which will add:
        # * <tt>Firm#clients</tt> (similar to <tt>Client.where(firm_id: id)</tt>)
        # * <tt>Firm#clients<<</tt>
        # * <tt>Firm#clients.delete</tt>
        # * <tt>Firm#clients.destroy</tt>
        # * <tt>Firm#clients=</tt>
        # * <tt>Firm#client_ids</tt>
        # * <tt>Firm#client_ids=</tt>
        # * <tt>Firm#clients.clear</tt>
        # * <tt>Firm#clients.empty?</tt> (similar to <tt>firm.clients.size == 0</tt>)
        # * <tt>Firm#clients.size</tt> (similar to <tt>Client.count "firm_id = #{id}"</tt>)
        # * <tt>Firm#clients.find</tt> (similar to <tt>Client.where(firm_id: id).find(id)</tt>)
        # * <tt>Firm#clients.exists?(name: 'ACME')</tt> (similar to <tt>Client.exists?(name: 'ACME', firm_id: firm.id)</tt>)
        # * <tt>Firm#clients.build</tt> (similar to <tt>Client.new(firm_id: id)</tt>)
        # * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new(firm_id: id); c.save; c</tt>)
        # * <tt>Firm#clients.create!</tt> (similar to <tt>c = Client.new(firm_id: id); c.save!</tt>)
        # * <tt>Firm#clients.reload</tt>
        # The declaration can also include an +options+ hash to specialize the behavior of the association.
        #
        # === Scopes
        #
        # You can pass a second argument +scope+ as a callable (i.e. proc or
        # lambda) to retrieve a specific set of records or customize the generated
        # query when you access the associated collection.
        #
        # Scope examples:
        #   has_many :comments, -> { where(author_id: 1) }
        #   has_many :employees, -> { joins(:address) }
        #   has_many :posts, ->(blog) { where("max_post_length > ?", blog.max_post_length) }
        #
        # === Extensions
        #
        # The +extension+ argument allows you to pass a block into a has_many
        # association. This is useful for adding new finders, creators, and other
        # factory-type methods to be used as part of the association.
        #
        # Extension examples:
        #   has_many :employees do
        #     def find_or_create_by_name(name)
        #       first_name, last_name = name.split(" ", 2)
        #       find_or_create_by(first_name: first_name, last_name: last_name)
        #     end
        #   end
        #
        # === Options
        # [:class_name]
        #   Specify the class name of the association. Use it only if that name can't be inferred
        #   from the association name. So <tt>has_many :products</tt> will by default be linked
        #   to the +Product+ class, but if the real class name is +SpecialProduct+, you'll have to
        #   specify it with this option.
        # [:foreign_key]
        #   Specify the foreign key used for the association. By default this is guessed to be the name
        #   of this class in lower-case and "_id" suffixed. So a Person class that makes a #has_many
        #   association will use "person_id" as the default <tt>:foreign_key</tt>.
        #
        #   Setting the <tt>:foreign_key</tt> option prevents automatic detection of the association's
        #   inverse, so it is generally a good idea to set the <tt>:inverse_of</tt> option as well.
        # [:foreign_type]
        #   Specify the column used to store the associated object's type, if this is a polymorphic
        #   association. By default this is guessed to be the name of the polymorphic association
        #   specified on "as" option with a "_type" suffix. So a class that defines a
        #   <tt>has_many :tags, as: :taggable</tt> association will use "taggable_type" as the
        #   default <tt>:foreign_type</tt>.
        # [:primary_key]
        #   Specify the name of the column to use as the primary key for the association. By default this is +id+.
        # [:dependent]
        #   Controls what happens to the associated objects when
        #   their owner is destroyed. Note that these are implemented as
        #   callbacks, and Rails executes callbacks in order. Therefore, other
        #   similar callbacks may affect the <tt>:dependent</tt> behavior, and the
        #   <tt>:dependent</tt> behavior may affect other callbacks.
        #
        #   * <tt>nil</tt> do nothing (default).
        #   * <tt>:destroy</tt> causes all the associated objects to also be destroyed.
        #   * <tt>:destroy_async</tt> destroys all the associated objects in a background job. <b>WARNING:</b> Do not use
        #     this option if the association is backed by foreign key constraints in your database. The foreign key
        #     constraint actions will occur inside the same transaction that deletes its owner.
        #   * <tt>:delete_all</tt> causes all the associated objects to be deleted directly from the database (so callbacks will not be executed).
        #   * <tt>:nullify</tt> causes the foreign keys to be set to +NULL+. Polymorphic type will also be nullified
        #     on polymorphic associations. Callbacks are not executed.
        #   * <tt>:restrict_with_exception</tt> causes an <tt>ActiveRecord::DeleteRestrictionError</tt> exception to be raised if there are any associated records.
        #   * <tt>:restrict_with_error</tt> causes an error to be added to the owner if there are any associated objects.
        #
        #   If using with the <tt>:through</tt> option, the association on the join model must be
        #   a #belongs_to, and the records which get deleted are the join records, rather than
        #   the associated records.
        #
        #   If using <tt>dependent: :destroy</tt> on a scoped association, only the scoped objects are destroyed.
        #   For example, if a Post model defines
        #   <tt>has_many :comments, -> { where published: true }, dependent: :destroy</tt> and <tt>destroy</tt> is
        #   called on a post, only published comments are destroyed. This means that any unpublished comments in the
        #   database would still contain a foreign key pointing to the now deleted post.
        # [:counter_cache]
        #   This option can be used to configure a custom named <tt>:counter_cache.</tt> You only need this option,
        #   when you customized the name of your <tt>:counter_cache</tt> on the #belongs_to association.
        # [:as]
        #   Specifies a polymorphic interface (See #belongs_to).
        # [:through]
        #   Specifies an association through which to perform the query. This can be any other type
        #   of association, including other <tt>:through</tt> associations. Options for <tt>:class_name</tt>,
        #   <tt>:primary_key</tt> and <tt>:foreign_key</tt> are ignored, as the association uses the
        #   source reflection.
        #
        #   If the association on the join model is a #belongs_to, the collection can be modified
        #   and the records on the <tt>:through</tt> model will be automatically created and removed
        #   as appropriate. Otherwise, the collection is read-only, so you should manipulate the
        #   <tt>:through</tt> association directly.
        #
        #   If you are going to modify the association (rather than just read from it), then it is
        #   a good idea to set the <tt>:inverse_of</tt> option on the source association on the
        #   join model. This allows associated records to be built which will automatically create
        #   the appropriate join model records when they are saved. (See the 'Association Join Models'
        #   and 'Setting Inverses' sections above.)
        # [:disable_joins]
        #   Specifies whether joins should be skipped for an association. If set to true, two or more queries
        #   will be generated. Note that in some cases, if order or limit is applied, it will be done in-memory
        #   due to database limitations. This option is only applicable on <tt>has_many :through</tt> associations as
        #   +has_many+ alone do not perform a join.
        # [:source]
        #   Specifies the source association name used by #has_many <tt>:through</tt> queries.
        #   Only use it if the name cannot be inferred from the association.
        #   <tt>has_many :subscribers, through: :subscriptions</tt> will look for either <tt>:subscribers</tt> or
        #   <tt>:subscriber</tt> on Subscription, unless a <tt>:source</tt> is given.
        # [:source_type]
        #   Specifies type of the source association used by #has_many <tt>:through</tt> queries where the source
        #   association is a polymorphic #belongs_to.
        # [:validate]
        #   When set to +true+, validates new objects added to association when saving the parent object. +true+ by default.
        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
        # [:autosave]
        #   If true, always save the associated objects or destroy them if marked for destruction,
        #   when saving the parent object. If false, never save or destroy the associated objects.
        #   By default, only save associated objects that are new records. This option is implemented as a
        #   +before_save+ callback. Because callbacks are run in the order they are defined, associated objects
        #   may need to be explicitly saved in any user-defined +before_save+ callbacks.
        #
        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for sets
        #   <tt>:autosave</tt> to <tt>true</tt>.
        # [:inverse_of]
        #   Specifies the name of the #belongs_to association on the associated object
        #   that is the inverse of this #has_many association.
        #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
        # [:extend]
        #   Specifies a module or array of modules that will be extended into the association object returned.
        #   Useful for defining methods on associations, especially when they should be shared between multiple
        #   association objects.
        # [:strict_loading]
        #   When set to +true+, enforces strict loading every time the associated record is loaded through this
        #   association.
        # [:ensuring_owner_was]
        #   Specifies an instance method to be called on the owner. The method must return true in order for the
        #   associated records to be deleted in a background job.
        #
        # Option examples:
        #   has_many :comments, -> { order("posted_on") }
        #   has_many :comments, -> { includes(:author) }
        #   has_many :people, -> { where(deleted: false).order("name") }, class_name: "Person"
        #   has_many :tracks, -> { order("position") }, dependent: :destroy
        #   has_many :comments, dependent: :nullify
        #   has_many :tags, as: :taggable
        #   has_many :reports, -> { readonly }
        #   has_many :subscribers, through: :subscriptions, source: :user
        #   has_many :subscribers, through: :subscriptions, disable_joins: true
        #   has_many :comments, strict_loading: true
        def has_many(name, scope = nil, **options, &extension)
          reflection = Builder::HasMany.build(self, name, scope, options, &extension)
          Reflection.add_reflection self, name, reflection
        end

        # Specifies a one-to-one association with another class. This method should only be used
        # if the other class contains the foreign key. If the current class contains the foreign key,
        # then you should use #belongs_to instead. See also ActiveRecord::Associations::ClassMethods's overview
        # on when to use #has_one and when to use #belongs_to.
        #
        # The following methods for retrieval and query of a single associated object will be added:
        #
        # +association+ is a placeholder for the symbol passed as the +name+ argument, so
        # <tt>has_one :manager</tt> would add among others <tt>manager.nil?</tt>.
        #
        # [association]
        #   Returns the associated object. +nil+ is returned if none is found.
        # [association=(associate)]
        #   Assigns the associate object, extracts the primary key, sets it as the foreign key,
        #   and saves the associate object. To avoid database inconsistencies, permanently deletes an existing
        #   associated object when assigning a new one, even if the new one isn't saved to database.
        # [build_association(attributes = {})]
        #   Returns a new object of the associated type that has been instantiated
        #   with +attributes+ and linked to this object through a foreign key, but has not
        #   yet been saved.
        # [create_association(attributes = {})]
        #   Returns a new object of the associated type that has been instantiated
        #   with +attributes+, linked to this object through a foreign key, and that
        #   has already been saved (if it passed the validation).
        # [create_association!(attributes = {})]
        #   Does the same as <tt>create_association</tt>, but raises ActiveRecord::RecordInvalid
        #   if the record is invalid.
        # [reload_association]
        #   Returns the associated object, forcing a database read.
        #
        # === Example
        #
        # An Account class declares <tt>has_one :beneficiary</tt>, which will add:
        # * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.where(account_id: id).first</tt>)
        # * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
        # * <tt>Account#build_beneficiary</tt> (similar to <tt>Beneficiary.new(account_id: id)</tt>)
        # * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new(account_id: id); b.save; b</tt>)
        # * <tt>Account#create_beneficiary!</tt> (similar to <tt>b = Beneficiary.new(account_id: id); b.save!; b</tt>)
        # * <tt>Account#reload_beneficiary</tt>
        #
        # === Scopes
        #
        # You can pass a second argument +scope+ as a callable (i.e. proc or
        # lambda) to retrieve a specific record or customize the generated query
        # when you access the associated object.
        #
        # Scope examples:
        #   has_one :author, -> { where(comment_id: 1) }
        #   has_one :employer, -> { joins(:company) }
        #   has_one :latest_post, ->(blog) { where("created_at > ?", blog.enabled_at) }
        #
        # === Options
        #
        # The declaration can also include an +options+ hash to specialize the behavior of the association.
        #
        # Options are:
        # [:class_name]
        #   Specify the class name of the association. Use it only if that name can't be inferred
        #   from the association name. So <tt>has_one :manager</tt> will by default be linked to the Manager class, but
        #   if the real class name is Person, you'll have to specify it with this option.
        # [:dependent]
        #   Controls what happens to the associated object when
        #   its owner is destroyed:
        #
        #   * <tt>nil</tt> do nothing (default).
        #   * <tt>:destroy</tt> causes the associated object to also be destroyed
        #   * <tt>:destroy_async</tt> causes the associated object to be destroyed in a background job. <b>WARNING:</b> Do not use
        #     this option if the association is backed by foreign key constraints in your database. The foreign key
        #     constraint actions will occur inside the same transaction that deletes its owner.
        #   * <tt>:delete</tt> causes the associated object to be deleted directly from the database (so callbacks will not execute)
        #   * <tt>:nullify</tt> causes the foreign key to be set to +NULL+. Polymorphic type column is also nullified
        #     on polymorphic associations. Callbacks are not executed.
        #   * <tt>:restrict_with_exception</tt> causes an <tt>ActiveRecord::DeleteRestrictionError</tt> exception to be raised if there is an associated record
        #   * <tt>:restrict_with_error</tt> causes an error to be added to the owner if there is an associated object
        #
        #   Note that <tt>:dependent</tt> option is ignored when using <tt>:through</tt> option.
        # [:foreign_key]
        #   Specify the foreign key used for the association. By default this is guessed to be the name
        #   of this class in lower-case and "_id" suffixed. So a Person class that makes a #has_one association
        #   will use "person_id" as the default <tt>:foreign_key</tt>.
        #
        #   Setting the <tt>:foreign_key</tt> option prevents automatic detection of the association's
        #   inverse, so it is generally a good idea to set the <tt>:inverse_of</tt> option as well.
        # [:foreign_type]
        #   Specify the column used to store the associated object's type, if this is a polymorphic
        #   association. By default this is guessed to be the name of the polymorphic association
        #   specified on "as" option with a "_type" suffix. So a class that defines a
        #   <tt>has_one :tag, as: :taggable</tt> association will use "taggable_type" as the
        #   default <tt>:foreign_type</tt>.
        # [:primary_key]
        #   Specify the method that returns the primary key used for the association. By default this is +id+.
        # [:as]
        #   Specifies a polymorphic interface (See #belongs_to).
        # [:through]
        #   Specifies a Join Model through which to perform the query. Options for <tt>:class_name</tt>,
        #   <tt>:primary_key</tt>, and <tt>:foreign_key</tt> are ignored, as the association uses the
        #   source reflection. You can only use a <tt>:through</tt> query through a #has_one
        #   or #belongs_to association on the join model.
        #
        #   If the association on the join model is a #belongs_to, the collection can be modified
        #   and the records on the <tt>:through</tt> model will be automatically created and removed
        #   as appropriate. Otherwise, the collection is read-only, so you should manipulate the
        #   <tt>:through</tt> association directly.
        #
        #   If you are going to modify the association (rather than just read from it), then it is
        #   a good idea to set the <tt>:inverse_of</tt> option on the source association on the
        #   join model. This allows associated records to be built which will automatically create
        #   the appropriate join model records when they are saved. (See the 'Association Join Models'
        #   and 'Setting Inverses' sections above.)
        # [:disable_joins]
        #   Specifies whether joins should be skipped for an association. If set to true, two or more queries
        #   will be generated. Note that in some cases, if order or limit is applied, it will be done in-memory
        #   due to database limitations. This option is only applicable on <tt>has_one :through</tt> associations as
        #   +has_one+ alone does not perform a join.
        # [:source]
        #   Specifies the source association name used by #has_one <tt>:through</tt> queries.
        #   Only use it if the name cannot be inferred from the association.
        #   <tt>has_one :favorite, through: :favorites</tt> will look for a
        #   <tt>:favorite</tt> on Favorite, unless a <tt>:source</tt> is given.
        # [:source_type]
        #   Specifies type of the source association used by #has_one <tt>:through</tt> queries where the source
        #   association is a polymorphic #belongs_to.
        # [:validate]
        #   When set to +true+, validates new objects added to association when saving the parent object. +false+ by default.
        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
        # [:autosave]
        #   If true, always save the associated object or destroy it if marked for destruction,
        #   when saving the parent object. If false, never save or destroy the associated object.
        #   By default, only save the associated object if it's a new record.
        #
        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for sets
        #   <tt>:autosave</tt> to <tt>true</tt>.
        # [:inverse_of]
        #   Specifies the name of the #belongs_to association on the associated object
        #   that is the inverse of this #has_one association.
        #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
        # [:required]
        #   When set to +true+, the association will also have its presence validated.
        #   This will validate the association itself, not the id. You can use
        #   +:inverse_of+ to avoid an extra query during validation.
        # [:strict_loading]
        #   Enforces strict loading every time the associated record is loaded through this association.
        # [:ensuring_owner_was]
        #   Specifies an instance method to be called on the owner. The method must return true in order for the
        #   associated records to be deleted in a background job.
        #
        # Option examples:
        #   has_one :credit_card, dependent: :destroy  # destroys the associated credit card
        #   has_one :credit_card, dependent: :nullify  # updates the associated records foreign
        #                                                 # key value to NULL rather than destroying it
        #   has_one :last_comment, -> { order('posted_on') }, class_name: "Comment"
        #   has_one :project_manager, -> { where(role: 'project_manager') }, class_name: "Person"
        #   has_one :attachment, as: :attachable
        #   has_one :boss, -> { readonly }
        #   has_one :club, through: :membership
        #   has_one :club, through: :membership, disable_joins: true
        #   has_one :primary_address, -> { where(primary: true) }, through: :addressables, source: :addressable
        #   has_one :credit_card, required: true
        #   has_one :credit_card, strict_loading: true
        def has_one(name, scope = nil, **options)
          reflection = Builder::HasOne.build(self, name, scope, options)
          Reflection.add_reflection self, name, reflection
        end

        # Specifies a one-to-one association with another class. This method should only be used
        # if this class contains the foreign key. If the other class contains the foreign key,
        # then you should use #has_one instead. See also ActiveRecord::Associations::ClassMethods's overview
        # on when to use #has_one and when to use #belongs_to.
        #
        # Methods will be added for retrieval and query for a single associated object, for which
        # this object holds an id:
        #
        # +association+ is a placeholder for the symbol passed as the +name+ argument, so
        # <tt>belongs_to :author</tt> would add among others <tt>author.nil?</tt>.
        #
        # [association]
        #   Returns the associated object. +nil+ is returned if none is found.
        # [association=(associate)]
        #   Assigns the associate object, extracts the primary key, and sets it as the foreign key.
        #   No modification or deletion of existing records takes place.
        # [build_association(attributes = {})]
        #   Returns a new object of the associated type that has been instantiated
        #   with +attributes+ and linked to this object through a foreign key, but has not yet been saved.
        # [create_association(attributes = {})]
        #   Returns a new object of the associated type that has been instantiated
        #   with +attributes+, linked to this object through a foreign key, and that
        #   has already been saved (if it passed the validation).
        # [create_association!(attributes = {})]
        #   Does the same as <tt>create_association</tt>, but raises ActiveRecord::RecordInvalid
        #   if the record is invalid.
        # [reload_association]
        #   Returns the associated object, forcing a database read.
        # [association_changed?]
        #   Returns true if a new associate object has been assigned and the next save will update the foreign key.
        # [association_previously_changed?]
        #   Returns true if the previous save updated the association to reference a new associate object.
        #
        # === Example
        #
        # A Post class declares <tt>belongs_to :author</tt>, which will add:
        # * <tt>Post#author</tt> (similar to <tt>Author.find(author_id)</tt>)
        # * <tt>Post#author=(author)</tt> (similar to <tt>post.author_id = author.id</tt>)
        # * <tt>Post#build_author</tt> (similar to <tt>post.author = Author.new</tt>)
        # * <tt>Post#create_author</tt> (similar to <tt>post.author = Author.new; post.author.save; post.author</tt>)
        # * <tt>Post#create_author!</tt> (similar to <tt>post.author = Author.new; post.author.save!; post.author</tt>)
        # * <tt>Post#reload_author</tt>
        # * <tt>Post#author_changed?</tt>
        # * <tt>Post#author_previously_changed?</tt>
        # The declaration can also include an +options+ hash to specialize the behavior of the association.
        #
        # === Scopes
        #
        # You can pass a second argument +scope+ as a callable (i.e. proc or
        # lambda) to retrieve a specific record or customize the generated query
        # when you access the associated object.
        #
        # Scope examples:
        #   belongs_to :firm, -> { where(id: 2) }
        #   belongs_to :user, -> { joins(:friends) }
        #   belongs_to :level, ->(game) { where("game_level > ?", game.current_level) }
        #
        # === Options
        #
        # [:class_name]
        #   Specify the class name of the association. Use it only if that name can't be inferred
        #   from the association name. So <tt>belongs_to :author</tt> will by default be linked to the Author class, but
        #   if the real class name is Person, you'll have to specify it with this option.
        # [:foreign_key]
        #   Specify the foreign key used for the association. By default this is guessed to be the name
        #   of the association with an "_id" suffix. So a class that defines a <tt>belongs_to :person</tt>
        #   association will use "person_id" as the default <tt>:foreign_key</tt>. Similarly,
        #   <tt>belongs_to :favorite_person, class_name: "Person"</tt> will use a foreign key
        #   of "favorite_person_id".
        #
        #   Setting the <tt>:foreign_key</tt> option prevents automatic detection of the association's
        #   inverse, so it is generally a good idea to set the <tt>:inverse_of</tt> option as well.
        # [:foreign_type]
        #   Specify the column used to store the associated object's type, if this is a polymorphic
        #   association. By default this is guessed to be the name of the association with a "_type"
        #   suffix. So a class that defines a <tt>belongs_to :taggable, polymorphic: true</tt>
        #   association will use "taggable_type" as the default <tt>:foreign_type</tt>.
        # [:primary_key]
        #   Specify the method that returns the primary key of associated object used for the association.
        #   By default this is +id+.
        # [:dependent]
        #   If set to <tt>:destroy</tt>, the associated object is destroyed when this object is. If set to
        #   <tt>:delete</tt>, the associated object is deleted *without* calling its destroy method. If set to
        #   <tt>:destroy_async</tt>, the associated object is scheduled to be destroyed in a background job.
        #   This option should not be specified when #belongs_to is used in conjunction with
        #   a #has_many relationship on another class because of the potential to leave
        #   orphaned records behind.
        # [:counter_cache]
        #   Caches the number of belonging objects on the associate class through the use of CounterCache::ClassMethods#increment_counter
        #   and CounterCache::ClassMethods#decrement_counter. The counter cache is incremented when an object of this
        #   class is created and decremented when it's destroyed. This requires that a column
        #   named <tt>#{table_name}_count</tt> (such as +comments_count+ for a belonging Comment class)
        #   is used on the associate class (such as a Post class) - that is the migration for
        #   <tt>#{table_name}_count</tt> is created on the associate class (such that <tt>Post.comments_count</tt> will
        #   return the count cached, see note below). You can also specify a custom counter
        #   cache column by providing a column name instead of a +true+/+false+ value to this
        #   option (e.g., <tt>counter_cache: :my_custom_counter</tt>.)
        #   Note: Specifying a counter cache will add it to that model's list of readonly attributes
        #   using +attr_readonly+.
        # [:polymorphic]
        #   Specify this association is a polymorphic association by passing +true+.
        #   Note: If you've enabled the counter cache, then you may want to add the counter cache attribute
        #   to the +attr_readonly+ list in the associated classes (e.g. <tt>class Post; attr_readonly :comments_count; end</tt>).
        # [:validate]
        #   When set to +true+, validates new objects added to association when saving the parent object. +false+ by default.
        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
        # [:autosave]
        #   If true, always save the associated object or destroy it if marked for destruction, when
        #   saving the parent object.
        #   If false, never save or destroy the associated object.
        #   By default, only save the associated object if it's a new record.
        #
        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for
        #   sets <tt>:autosave</tt> to <tt>true</tt>.
        # [:touch]
        #   If true, the associated object will be touched (the updated_at/on attributes set to current time)
        #   when this record is either saved or destroyed. If you specify a symbol, that attribute
        #   will be updated with the current time in addition to the updated_at/on attribute.
        #   Please note that with touching no validation is performed and only the +after_touch+,
        #   +after_commit+ and +after_rollback+ callbacks are executed.
        # [:inverse_of]
        #   Specifies the name of the #has_one or #has_many association on the associated
        #   object that is the inverse of this #belongs_to association.
        #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail.
        # [:optional]
        #   When set to +true+, the association will not have its presence validated.
        # [:required]
        #   When set to +true+, the association will also have its presence validated.
        #   This will validate the association itself, not the id. You can use
        #   +:inverse_of+ to avoid an extra query during validation.
        #   NOTE: <tt>required</tt> is set to <tt>true</tt> by default and is deprecated. If
        #   you don't want to have association presence validated, use <tt>optional: true</tt>.
        # [:default]
        #   Provide a callable (i.e. proc or lambda) to specify that the association should
        #   be initialized with a particular record before validation.
        # [:strict_loading]
        #   Enforces strict loading every time the associated record is loaded through this association.
        # [:ensuring_owner_was]
        #   Specifies an instance method to be called on the owner. The method must return true in order for the
        #   associated records to be deleted in a background job.
        #
        # Option examples:
        #   belongs_to :firm, foreign_key: "client_of"
        #   belongs_to :person, primary_key: "name", foreign_key: "person_name"
        #   belongs_to :author, class_name: "Person", foreign_key: "author_id"
        #   belongs_to :valid_coupon, ->(o) { where "discounts > ?", o.payments_count },
        #                             class_name: "Coupon", foreign_key: "coupon_id"
        #   belongs_to :attachable, polymorphic: true
        #   belongs_to :project, -> { readonly }
        #   belongs_to :post, counter_cache: true
        #   belongs_to :comment, touch: true
        #   belongs_to :company, touch: :employees_last_updated_at
        #   belongs_to :user, optional: true
        #   belongs_to :account, default: -> { company.account }
        #   belongs_to :account, strict_loading: true
        def belongs_to(name, scope = nil, **options)
          reflection = Builder::BelongsTo.build(self, name, scope, options)
          Reflection.add_reflection self, name, reflection
        end

        # Specifies a many-to-many relationship with another class. This associates two classes via an
        # intermediate join table. Unless the join table is explicitly specified as an option, it is
        # guessed using the lexical order of the class names. So a join between Developer and Project
        # will give the default join table name of "developers_projects" because "D" precedes "P" alphabetically.
        # Note that this precedence is calculated using the <tt><</tt> operator for String. This
        # means that if the strings are of different lengths, and the strings are equal when compared
        # up to the shortest length, then the longer string is considered of higher
        # lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers"
        # to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes",
        # but it in fact generates a join table name of "paper_boxes_papers". Be aware of this caveat, and use the
        # custom <tt>:join_table</tt> option if you need to.
        # If your tables share a common prefix, it will only appear once at the beginning. For example,
        # the tables "catalog_categories" and "catalog_products" generate a join table name of "catalog_categories_products".
        #
        # The join table should not have a primary key or a model associated with it. You must manually generate the
        # join table with a migration such as this:
        #
        #   class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration[7.1]
        #     def change
        #       create_join_table :developers, :projects
        #     end
        #   end
        #
        # It's also a good idea to add indexes to each of those columns to speed up the joins process.
        # However, in MySQL it is advised to add a compound index for both of the columns as MySQL only
        # uses one index per table during the lookup.
        #
        # Adds the following methods for retrieval and query:
        #
        # +collection+ is a placeholder for the symbol passed as the +name+ argument, so
        # <tt>has_and_belongs_to_many :categories</tt> would add among others <tt>categories.empty?</tt>.
        #
        # [collection]
        #   Returns a Relation of all the associated objects.
        #   An empty Relation is returned if none are found.
        # [collection<<(object, ...)]
        #   Adds one or more objects to the collection by creating associations in the join table
        #   (<tt>collection.push</tt> and <tt>collection.concat</tt> are aliases to this method).
        #   Note that this operation instantly fires update SQL without waiting for the save or update call on the
        #   parent object, unless the parent object is a new record.
        # [collection.delete(object, ...)]
        #   Removes one or more objects from the collection by removing their associations from the join table.
        #   This does not destroy the objects.
        # [collection.destroy(object, ...)]
        #   Removes one or more objects from the collection by running destroy on each association in the join table, overriding any dependent option.
        #   This does not destroy the objects.
        # [collection=objects]
        #   Replaces the collection's content by deleting and adding objects as appropriate.
        # [collection_singular_ids]
        #   Returns an array of the associated objects' ids.
        # [collection_singular_ids=ids]
        #   Replace the collection by the objects identified by the primary keys in +ids+.
        # [collection.clear]
        #   Removes every object from the collection. This does not destroy the objects.
        # [collection.empty?]
        #   Returns +true+ if there are no associated objects.
        # [collection.size]
        #   Returns the number of associated objects.
        # [collection.find(id)]
        #   Finds an associated object responding to the +id+ and that
        #   meets the condition that it has to be associated with this object.
        #   Uses the same rules as ActiveRecord::FinderMethods#find.
        # [collection.exists?(...)]
        #   Checks whether an associated object with the given conditions exists.
        #   Uses the same rules as ActiveRecord::FinderMethods#exists?.
        # [collection.build(attributes = {})]
        #   Returns a new object of the collection type that has been instantiated
        #   with +attributes+ and linked to this object through the join table, but has not yet been saved.
        # [collection.create(attributes = {})]
        #   Returns a new object of the collection type that has been instantiated
        #   with +attributes+, linked to this object through the join table, and that has already been
        #   saved (if it passed the validation).
        # [collection.reload]
        #   Returns a Relation of all of the associated objects, forcing a database read.
        #   An empty Relation is returned if none are found.
        #
        # === Example
        #
        # A Developer class declares <tt>has_and_belongs_to_many :projects</tt>, which will add:
        # * <tt>Developer#projects</tt>
        # * <tt>Developer#projects<<</tt>
        # * <tt>Developer#projects.delete</tt>
        # * <tt>Developer#projects.destroy</tt>
        # * <tt>Developer#projects=</tt>
        # * <tt>Developer#project_ids</tt>
        # * <tt>Developer#project_ids=</tt>
        # * <tt>Developer#projects.clear</tt>
        # * <tt>Developer#projects.empty?</tt>
        # * <tt>Developer#projects.size</tt>
        # * <tt>Developer#projects.find(id)</tt>
        # * <tt>Developer#projects.exists?(...)</tt>
        # * <tt>Developer#projects.build</tt> (similar to <tt>Project.new(developer_id: id)</tt>)
        # * <tt>Developer#projects.create</tt> (similar to <tt>c = Project.new(developer_id: id); c.save; c</tt>)
        # * <tt>Developer#projects.reload</tt>
        # The declaration may include an +options+ hash to specialize the behavior of the association.
        #
        # === Scopes
        #
        # You can pass a second argument +scope+ as a callable (i.e. proc or
        # lambda) to retrieve a specific set of records or customize the generated
        # query when you access the associated collection.
        #
        # Scope examples:
        #   has_and_belongs_to_many :projects, -> { includes(:milestones, :manager) }
        #   has_and_belongs_to_many :categories, ->(post) {
        #     where("default_category = ?", post.default_category)
        #   }
        #
        # === Extensions
        #
        # The +extension+ argument allows you to pass a block into a
        # has_and_belongs_to_many association. This is useful for adding new
        # finders, creators, and other factory-type methods to be used as part of
        # the association.
        #
        # Extension examples:
        #   has_and_belongs_to_many :contractors do
        #     def find_or_create_by_name(name)
        #       first_name, last_name = name.split(" ", 2)
        #       find_or_create_by(first_name: first_name, last_name: last_name)
        #     end
        #   end
        #
        # === Options
        #
        # [:class_name]
        #   Specify the class name of the association. Use it only if that name can't be inferred
        #   from the association name. So <tt>has_and_belongs_to_many :projects</tt> will by default be linked to the
        #   Project class, but if the real class name is SuperProject, you'll have to specify it with this option.
        # [:join_table]
        #   Specify the name of the join table if the default based on lexical order isn't what you want.
        #   <b>WARNING:</b> If you're overwriting the table name of either class, the +table_name+ method
        #   MUST be declared underneath any #has_and_belongs_to_many declaration in order to work.
        # [:foreign_key]
        #   Specify the foreign key used for the association. By default this is guessed to be the name
        #   of this class in lower-case and "_id" suffixed. So a Person class that makes
        #   a #has_and_belongs_to_many association to Project will use "person_id" as the
        #   default <tt>:foreign_key</tt>.
        #
        #   Setting the <tt>:foreign_key</tt> option prevents automatic detection of the association's
        #   inverse, so it is generally a good idea to set the <tt>:inverse_of</tt> option as well.
        # [:association_foreign_key]
        #   Specify the foreign key used for the association on the receiving side of the association.
        #   By default this is guessed to be the name of the associated class in lower-case and "_id" suffixed.
        #   So if a Person class makes a #has_and_belongs_to_many association to Project,
        #   the association will use "project_id" as the default <tt>:association_foreign_key</tt>.
        # [:validate]
        #   When set to +true+, validates new objects added to association when saving the parent object. +true+ by default.
        #   If you want to ensure associated objects are revalidated on every update, use +validates_associated+.
        # [:autosave]
        #   If true, always save the associated objects or destroy them if marked for destruction, when
        #   saving the parent object.
        #   If false, never save or destroy the associated objects.
        #   By default, only save associated objects that are new records.
        #
        #   Note that NestedAttributes::ClassMethods#accepts_nested_attributes_for sets
        #   <tt>:autosave</tt> to <tt>true</tt>.
        # [:strict_loading]
        #   Enforces strict loading every time an associated record is loaded through this association.
        #
        # Option examples:
        #   has_and_belongs_to_many :projects
        #   has_and_belongs_to_many :projects, -> { includes(:milestones, :manager) }
        #   has_and_belongs_to_many :nations, class_name: "Country"
        #   has_and_belongs_to_many :categories, join_table: "prods_cats"
        #   has_and_belongs_to_many :categories, -> { readonly }
        #   has_and_belongs_to_many :categories, strict_loading: true
        def has_and_belongs_to_many(name, scope = nil, **options, &extension)
          habtm_reflection = ActiveRecord::Reflection::HasAndBelongsToManyReflection.new(name, scope, options, self)

          builder = Builder::HasAndBelongsToMany.new name, self, options

          join_model = builder.through_model

          const_set join_model.name, join_model
          private_constant join_model.name

          middle_reflection = builder.middle_reflection join_model

          Builder::HasMany.define_callbacks self, middle_reflection
          Reflection.add_reflection self, middle_reflection.name, middle_reflection
          middle_reflection.parent_reflection = habtm_reflection

          include Module.new {
            class_eval <<-RUBY, __FILE__, __LINE__ + 1
              def destroy_associations
                association(:#{middle_reflection.name}).delete_all(:delete_all)
                association(:#{name}).reset
                super
              end
            RUBY
          }

          hm_options = {}
          hm_options[:through] = middle_reflection.name
          hm_options[:source] = join_model.right_reflection.name

          [:before_add, :after_add, :before_remove, :after_remove, :autosave, :validate, :join_table, :class_name, :extend, :strict_loading].each do |k|
            hm_options[k] = options[k] if options.key? k
          end

          has_many name, scope, **hm_options, &extension
          _reflections[name.to_s].parent_reflection = habtm_reflection
        end
      end
  end
end

asynchronous_queries_tracker.rb

# frozen_string_literal: true

module ActiveRecord
  class AsynchronousQueriesTracker # :nodoc:
    module NullSession # :nodoc:
      class << self
        def active?
          true
        end

        def finalize
        end
      end
    end

    class Session # :nodoc:
      def initialize
        @active = true
      end

      def active?
        @active
      end

      def finalize
        @active = false
      end
    end

    class << self
      def install_executor_hooks(executor = ActiveSupport::Executor)
        executor.register_hook(self)
      end

      def run
        ActiveRecord::Base.asynchronous_queries_tracker.start_session
      end

      def complete(asynchronous_queries_tracker)
        asynchronous_queries_tracker.finalize_session
      end
    end

    attr_reader :current_session

    def initialize
      @current_session = NullSession
    end

    def start_session
      @current_session = Session.new
      self
    end

    def finalize_session
      @current_session.finalize
      @current_session = NullSession
    end
  end
end

attribute.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Attributes
    class Attribute < Struct.new :relation, :name
      include Arel::Expressions
      include Arel::Predications
      include Arel::AliasPredication
      include Arel::OrderPredications
      include Arel::Math

      def type_caster
        relation.type_for_attribute(name)
      end

      ###
      # Create a node for lowering this attribute
      def lower
        relation.lower self
      end

      def type_cast_for_database(value)
        relation.type_cast_for_database(name, value)
      end

      def able_to_type_cast?
        relation.able_to_type_cast?
      end
    end
  end

  Attribute = Attributes::Attribute
end

attribute_assignment.rb

# frozen_string_literal: true

require "active_model/forbidden_attributes_protection"

module ActiveRecord
  module AttributeAssignment
    include ActiveModel::AttributeAssignment

    private
      def _assign_attributes(attributes)
        multi_parameter_attributes = nested_parameter_attributes = nil

        attributes.each do |k, v|
          key = k.to_s

          if key.include?("(")
            (multi_parameter_attributes ||= {})[key] = v
          elsif v.is_a?(Hash)
            (nested_parameter_attributes ||= {})[key] = v
          else
            _assign_attribute(key, v)
          end
        end

        assign_nested_parameter_attributes(nested_parameter_attributes) if nested_parameter_attributes
        assign_multiparameter_attributes(multi_parameter_attributes) if multi_parameter_attributes
      end

      # Assign any deferred nested attributes after the base attributes have been set.
      def assign_nested_parameter_attributes(pairs)
        pairs.each { |k, v| _assign_attribute(k, v) }
      end

      # Instantiates objects for all attribute classes that needs more than one constructor parameter. This is done
      # by calling new on the column type or aggregation type (through composed_of) object with these parameters.
      # So having the pairs written_on(1) = "2004", written_on(2) = "6", written_on(3) = "24", will instantiate
      # written_on (a date type) with Date.new("2004", "6", "24"). You can also specify a typecast character in the
      # parentheses to have the parameters typecasted before they're used in the constructor. Use i for Integer and
      # f for Float. If all the values for a given attribute are empty, the attribute will be set to +nil+.
      def assign_multiparameter_attributes(pairs)
        execute_callstack_for_multiparameter_attributes(
          extract_callstack_for_multiparameter_attributes(pairs)
        )
      end

      def execute_callstack_for_multiparameter_attributes(callstack)
        errors = []
        callstack.each do |name, values_with_empty_parameters|
          if values_with_empty_parameters.each_value.all?(NilClass)
            values = nil
          else
            values = values_with_empty_parameters
          end
          send("#{name}=", values)
        rescue => ex
          errors << AttributeAssignmentError.new("error on assignment #{values_with_empty_parameters.values.inspect} to #{name} (#{ex.message})", ex, name)
        end
        unless errors.empty?
          error_descriptions = errors.map(&:message).join(",")
          raise MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes [#{error_descriptions}]"
        end
      end

      def extract_callstack_for_multiparameter_attributes(pairs)
        attributes = {}

        pairs.each do |(multiparameter_name, value)|
          attribute_name = multiparameter_name.split("(").first
          attributes[attribute_name] ||= {}

          parameter_value = value.empty? ? nil : type_cast_attribute_value(multiparameter_name, value)
          attributes[attribute_name][find_parameter_position(multiparameter_name)] ||= parameter_value
        end

        attributes
      end

      def type_cast_attribute_value(multiparameter_name, value)
        multiparameter_name =~ /\([0-9]*([if])\)/ ? value.send("to_" + $1) : value
      end

      def find_parameter_position(multiparameter_name)
        multiparameter_name.scan(/\(([0-9]*).*\)/).first.first.to_i
      end
  end
end

attribute_methods.rb

# frozen_string_literal: true

require "mutex_m"
require "active_support/core_ext/enumerable"

module ActiveRecord
  # = Active Record Attribute Methods
  module AttributeMethods
    extend ActiveSupport::Concern
    include ActiveModel::AttributeMethods

    included do
      initialize_generated_modules
      include Read
      include Write
      include BeforeTypeCast
      include Query
      include PrimaryKey
      include TimeZoneConversion
      include Dirty
      include Serialization
    end

    RESTRICTED_CLASS_METHODS = %w(private public protected allocate new name parent superclass)

    class GeneratedAttributeMethods < Module # :nodoc:
      include Mutex_m
    end

    class << self
      def dangerous_attribute_methods # :nodoc:
        @dangerous_attribute_methods ||= (
          Base.instance_methods +
          Base.private_instance_methods -
          Base.superclass.instance_methods -
          Base.superclass.private_instance_methods
        ).map { |m| -m.to_s }.to_set.freeze
      end
    end

    module ClassMethods
      def inherited(child_class) # :nodoc:
        child_class.initialize_generated_modules
        super
      end

      def initialize_generated_modules # :nodoc:
        @generated_attribute_methods = const_set(:GeneratedAttributeMethods, GeneratedAttributeMethods.new)
        private_constant :GeneratedAttributeMethods
        @attribute_methods_generated = false
        include @generated_attribute_methods

        super
      end

      # Generates all the attribute related methods for columns in the database
      # accessors, mutators and query methods.
      def define_attribute_methods # :nodoc:
        return false if @attribute_methods_generated
        # Use a mutex; we don't want two threads simultaneously trying to define
        # attribute methods.
        generated_attribute_methods.synchronize do
          return false if @attribute_methods_generated
          superclass.define_attribute_methods unless base_class?
          super(attribute_names)
          @attribute_methods_generated = true
        end
      end

      def undefine_attribute_methods # :nodoc:
        generated_attribute_methods.synchronize do
          super if defined?(@attribute_methods_generated) && @attribute_methods_generated
          @attribute_methods_generated = false
        end
      end

      # Raises an ActiveRecord::DangerousAttributeError exception when an
      # \Active \Record method is defined in the model, otherwise +false+.
      #
      #   class Person < ActiveRecord::Base
      #     def save
      #       'already defined by Active Record'
      #     end
      #   end
      #
      #   Person.instance_method_already_implemented?(:save)
      #   # => ActiveRecord::DangerousAttributeError: save is defined by Active Record. Check to make sure that you don't have an attribute or method with the same name.
      #
      #   Person.instance_method_already_implemented?(:name)
      #   # => false
      def instance_method_already_implemented?(method_name)
        if dangerous_attribute_method?(method_name)
          raise DangerousAttributeError, "#{method_name} is defined by Active Record. Check to make sure that you don't have an attribute or method with the same name."
        end

        if superclass == Base
          super
        else
          # If ThisClass < ... < SomeSuperClass < ... < Base and SomeSuperClass
          # defines its own attribute method, then we don't want to override that.
          defined = method_defined_within?(method_name, superclass, Base) &&
            ! superclass.instance_method(method_name).owner.is_a?(GeneratedAttributeMethods)
          defined || super
        end
      end

      # A method name is 'dangerous' if it is already (re)defined by Active Record, but
      # not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
      def dangerous_attribute_method?(name) # :nodoc:
        ::ActiveRecord::AttributeMethods.dangerous_attribute_methods.include?(name.to_s)
      end

      def method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc:
        if klass.method_defined?(name) || klass.private_method_defined?(name)
          if superklass.method_defined?(name) || superklass.private_method_defined?(name)
            klass.instance_method(name).owner != superklass.instance_method(name).owner
          else
            true
          end
        else
          false
        end
      end

      # A class method is 'dangerous' if it is already (re)defined by Active Record, but
      # not by any ancestors. (So 'puts' is not dangerous but 'new' is.)
      def dangerous_class_method?(method_name)
        return true if RESTRICTED_CLASS_METHODS.include?(method_name.to_s)

        if Base.respond_to?(method_name, true)
          if Object.respond_to?(method_name, true)
            Base.method(method_name).owner != Object.method(method_name).owner
          else
            true
          end
        else
          false
        end
      end

      # Returns +true+ if +attribute+ is an attribute method and table exists,
      # +false+ otherwise.
      #
      #   class Person < ActiveRecord::Base
      #   end
      #
      #   Person.attribute_method?('name')   # => true
      #   Person.attribute_method?(:age=)    # => true
      #   Person.attribute_method?(:nothing) # => false
      def attribute_method?(attribute)
        super || (table_exists? && column_names.include?(attribute.to_s.delete_suffix("=")))
      end

      # Returns an array of column names as strings if it's not an abstract class and
      # table exists. Otherwise it returns an empty array.
      #
      #   class Person < ActiveRecord::Base
      #   end
      #
      #   Person.attribute_names
      #   # => ["id", "created_at", "updated_at", "name", "age"]
      def attribute_names
        @attribute_names ||= if !abstract_class? && table_exists?
          attribute_types.keys
        else
          []
        end.freeze
      end

      # Returns true if the given attribute exists, otherwise false.
      #
      #   class Person < ActiveRecord::Base
      #     alias_attribute :new_name, :name
      #   end
      #
      #   Person.has_attribute?('name')     # => true
      #   Person.has_attribute?('new_name') # => true
      #   Person.has_attribute?(:age)       # => true
      #   Person.has_attribute?(:nothing)   # => false
      def has_attribute?(attr_name)
        attr_name = attr_name.to_s
        attr_name = attribute_aliases[attr_name] || attr_name
        attribute_types.key?(attr_name)
      end

      def _has_attribute?(attr_name) # :nodoc:
        attribute_types.key?(attr_name)
      end
    end

    # A Person object with a name attribute can ask <tt>person.respond_to?(:name)</tt>,
    # <tt>person.respond_to?(:name=)</tt>, and <tt>person.respond_to?(:name?)</tt>
    # which will all return +true+. It also defines the attribute methods if they have
    # not been generated.
    #
    #   class Person < ActiveRecord::Base
    #   end
    #
    #   person = Person.new
    #   person.respond_to?(:name)    # => true
    #   person.respond_to?(:name=)   # => true
    #   person.respond_to?(:name?)   # => true
    #   person.respond_to?('age')    # => true
    #   person.respond_to?('age=')   # => true
    #   person.respond_to?('age?')   # => true
    #   person.respond_to?(:nothing) # => false
    def respond_to?(name, include_private = false)
      return false unless super

      # If the result is true then check for the select case.
      # For queries selecting a subset of columns, return false for unselected columns.
      # We check defined?(@attributes) not to issue warnings if called on objects that
      # have been allocated but not yet initialized.
      if defined?(@attributes)
        if name = self.class.symbol_column_to_string(name.to_sym)
          return _has_attribute?(name)
        end
      end

      true
    end

    # Returns +true+ if the given attribute is in the attributes hash, otherwise +false+.
    #
    #   class Person < ActiveRecord::Base
    #     alias_attribute :new_name, :name
    #   end
    #
    #   person = Person.new
    #   person.has_attribute?(:name)     # => true
    #   person.has_attribute?(:new_name) # => true
    #   person.has_attribute?('age')     # => true
    #   person.has_attribute?(:nothing)  # => false
    def has_attribute?(attr_name)
      attr_name = attr_name.to_s
      attr_name = self.class.attribute_aliases[attr_name] || attr_name
      @attributes.key?(attr_name)
    end

    def _has_attribute?(attr_name) # :nodoc:
      @attributes.key?(attr_name)
    end

    # Returns an array of names for the attributes available on this object.
    #
    #   class Person < ActiveRecord::Base
    #   end
    #
    #   person = Person.new
    #   person.attribute_names
    #   # => ["id", "created_at", "updated_at", "name", "age"]
    def attribute_names
      @attributes.keys
    end

    # Returns a hash of all the attributes with their names as keys and the values of the attributes as values.
    #
    #   class Person < ActiveRecord::Base
    #   end
    #
    #   person = Person.create(name: 'Francesco', age: 22)
    #   person.attributes
    #   # => {"id"=>3, "created_at"=>Sun, 21 Oct 2012 04:53:04, "updated_at"=>Sun, 21 Oct 2012 04:53:04, "name"=>"Francesco", "age"=>22}
    def attributes
      @attributes.to_hash
    end

    # Returns an <tt>#inspect</tt>-like string for the value of the
    # attribute +attr_name+. String attributes are truncated up to 50
    # characters. Other attributes return the value of <tt>#inspect</tt>
    # without modification.
    #
    #   person = Person.create!(name: 'David Heinemeier Hansson ' * 3)
    #
    #   person.attribute_for_inspect(:name)
    #   # => "\"David Heinemeier Hansson David Heinemeier Hansson ...\""
    #
    #   person.attribute_for_inspect(:created_at)
    #   # => "\"2012-10-22 00:15:07.000000000 +0000\""
    #
    #   person.attribute_for_inspect(:tag_ids)
    #   # => "[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]"
    def attribute_for_inspect(attr_name)
      attr_name = attr_name.to_s
      attr_name = self.class.attribute_aliases[attr_name] || attr_name
      value = _read_attribute(attr_name)
      format_for_inspect(attr_name, value)
    end

    # Returns +true+ if the specified +attribute+ has been set by the user or by a
    # database load and is neither +nil+ nor <tt>empty?</tt> (the latter only applies
    # to objects that respond to <tt>empty?</tt>, most notably Strings). Otherwise, +false+.
    # Note that it always returns +true+ with boolean attributes.
    #
    #   class Task < ActiveRecord::Base
    #   end
    #
    #   task = Task.new(title: '', is_done: false)
    #   task.attribute_present?(:title)   # => false
    #   task.attribute_present?(:is_done) # => true
    #   task.title = 'Buy milk'
    #   task.is_done = true
    #   task.attribute_present?(:title)   # => true
    #   task.attribute_present?(:is_done) # => true
    def attribute_present?(attr_name)
      attr_name = attr_name.to_s
      attr_name = self.class.attribute_aliases[attr_name] || attr_name
      value = _read_attribute(attr_name)
      !value.nil? && !(value.respond_to?(:empty?) && value.empty?)
    end

    # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
    # "2004-12-12" in a date column is cast to a date object, like Date.new(2004, 12, 12)). It raises
    # <tt>ActiveModel::MissingAttributeError</tt> if the identified attribute is missing.
    #
    # Note: +:id+ is always present.
    #
    #   class Person < ActiveRecord::Base
    #     belongs_to :organization
    #   end
    #
    #   person = Person.new(name: 'Francesco', age: '22')
    #   person[:name] # => "Francesco"
    #   person[:age]  # => 22
    #
    #   person = Person.select('id').first
    #   person[:name]            # => ActiveModel::MissingAttributeError: missing attribute: name
    #   person[:organization_id] # => ActiveModel::MissingAttributeError: missing attribute: organization_id
    def [](attr_name)
      read_attribute(attr_name) { |n| missing_attribute(n, caller) }
    end

    # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+.
    # (Alias for the protected #write_attribute method).
    #
    #   class Person < ActiveRecord::Base
    #   end
    #
    #   person = Person.new
    #   person[:age] = '22'
    #   person[:age] # => 22
    #   person[:age].class # => Integer
    def []=(attr_name, value)
      write_attribute(attr_name, value)
    end

    # Returns the name of all database fields which have been read from this
    # model. This can be useful in development mode to determine which fields
    # need to be selected. For performance critical pages, selecting only the
    # required fields can be an easy performance win (assuming you aren't using
    # all of the fields on the model).
    #
    # For example:
    #
    #   class PostsController < ActionController::Base
    #     after_action :print_accessed_fields, only: :index
    #
    #     def index
    #       @posts = Post.all
    #     end
    #
    #     private
    #
    #     def print_accessed_fields
    #       p @posts.first.accessed_fields
    #     end
    #   end
    #
    # Which allows you to quickly change your code to:
    #
    #   class PostsController < ActionController::Base
    #     def index
    #       @posts = Post.select(:id, :title, :author_id, :updated_at)
    #     end
    #   end
    def accessed_fields
      @attributes.accessed
    end

    private
      def attribute_method?(attr_name)
        # We check defined? because Syck calls respond_to? before actually calling initialize.
        defined?(@attributes) && @attributes.key?(attr_name)
      end

      def attributes_with_values(attribute_names)
        attribute_names.index_with { |name| @attributes[name] }
      end

      # Filters the primary keys, readonly attributes and virtual columns from the attribute names.
      def attributes_for_update(attribute_names)
        attribute_names &= self.class.column_names
        attribute_names.delete_if do |name|
          self.class.readonly_attribute?(name) ||
            column_for_attribute(name).virtual?
        end
      end

      # Filters out the virtual columns and also primary keys, from the attribute names, when the primary
      # key is to be generated (e.g. the id attribute has no value).
      def attributes_for_create(attribute_names)
        attribute_names &= self.class.column_names
        attribute_names.delete_if do |name|
          (pk_attribute?(name) && id.nil?) ||
            column_for_attribute(name).virtual?
        end
      end

      def format_for_inspect(name, value)
        if value.nil?
          value.inspect
        else
          inspected_value = if value.is_a?(String) && value.length > 50
            "#{value[0, 50]}...".inspect
          elsif value.is_a?(Date) || value.is_a?(Time)
            %("#{value.to_fs(:inspect)}")
          else
            value.inspect
          end

          inspection_filter.filter_param(name, inspected_value)
        end
      end

      def pk_attribute?(name)
        name == @primary_key
      end
  end
end

attributes.rb

# frozen_string_literal: true

require "active_model/attribute/user_provided_default"

module ActiveRecord
  # See ActiveRecord::Attributes::ClassMethods for documentation
  module Attributes
    extend ActiveSupport::Concern

    included do
      class_attribute :attributes_to_define_after_schema_loads, instance_accessor: false, default: {} # :internal:
    end

    module ClassMethods
      # Defines an attribute with a type on this model. It will override the
      # type of existing attributes if needed. This allows control over how
      # values are converted to and from SQL when assigned to a model. It also
      # changes the behavior of values passed to
      # {ActiveRecord::Base.where}[rdoc-ref:QueryMethods#where]. This will let you use
      # your domain objects across much of Active Record, without having to
      # rely on implementation details or monkey patching.
      #
      # +name+ The name of the methods to define attribute methods for, and the
      # column which this will persist to.
      #
      # +cast_type+ A symbol such as +:string+ or +:integer+, or a type object
      # to be used for this attribute. See the examples below for more
      # information about providing custom type objects.
      #
      # ==== Options
      #
      # The following options are accepted:
      #
      # +default+ The default value to use when no value is provided. If this option
      # is not passed, the previous default value (if any) will be used.
      # Otherwise, the default will be +nil+.
      #
      # +array+ (PostgreSQL only) specifies that the type should be an array (see the
      # examples below).
      #
      # +range+ (PostgreSQL only) specifies that the type should be a range (see the
      # examples below).
      #
      # When using a symbol for +cast_type+, extra options are forwarded to the
      # constructor of the type object.
      #
      # ==== Examples
      #
      # The type detected by Active Record can be overridden.
      #
      #   # db/schema.rb
      #   create_table :store_listings, force: true do |t|
      #     t.decimal :price_in_cents
      #   end
      #
      #   # app/models/store_listing.rb
      #   class StoreListing < ActiveRecord::Base
      #   end
      #
      #   store_listing = StoreListing.new(price_in_cents: '10.1')
      #
      #   # before
      #   store_listing.price_in_cents # => BigDecimal(10.1)
      #
      #   class StoreListing < ActiveRecord::Base
      #     attribute :price_in_cents, :integer
      #   end
      #
      #   # after
      #   store_listing.price_in_cents # => 10
      #
      # A default can also be provided.
      #
      #   # db/schema.rb
      #   create_table :store_listings, force: true do |t|
      #     t.string :my_string, default: "original default"
      #   end
      #
      #   StoreListing.new.my_string # => "original default"
      #
      #   # app/models/store_listing.rb
      #   class StoreListing < ActiveRecord::Base
      #     attribute :my_string, :string, default: "new default"
      #   end
      #
      #   StoreListing.new.my_string # => "new default"
      #
      #   class Product < ActiveRecord::Base
      #     attribute :my_default_proc, :datetime, default: -> { Time.now }
      #   end
      #
      #   Product.new.my_default_proc # => 2015-05-30 11:04:48 -0600
      #   sleep 1
      #   Product.new.my_default_proc # => 2015-05-30 11:04:49 -0600
      #
      # \Attributes do not need to be backed by a database column.
      #
      #   # app/models/my_model.rb
      #   class MyModel < ActiveRecord::Base
      #     attribute :my_string, :string
      #     attribute :my_int_array, :integer, array: true
      #     attribute :my_float_range, :float, range: true
      #   end
      #
      #   model = MyModel.new(
      #     my_string: "string",
      #     my_int_array: ["1", "2", "3"],
      #     my_float_range: "[1,3.5]",
      #   )
      #   model.attributes
      #   # =>
      #     {
      #       my_string: "string",
      #       my_int_array: [1, 2, 3],
      #       my_float_range: 1.0..3.5
      #     }
      #
      # Passing options to the type constructor
      #
      #   # app/models/my_model.rb
      #   class MyModel < ActiveRecord::Base
      #     attribute :small_int, :integer, limit: 2
      #   end
      #
      #   MyModel.create(small_int: 65537)
      #   # => Error: 65537 is out of range for the limit of two bytes
      #
      # ==== Creating Custom Types
      #
      # Users may also define their own custom types, as long as they respond
      # to the methods defined on the value type. The method +deserialize+ or
      # +cast+ will be called on your type object, with raw input from the
      # database or from your controllers. See ActiveModel::Type::Value for the
      # expected API. It is recommended that your type objects inherit from an
      # existing type, or from ActiveRecord::Type::Value
      #
      #   class MoneyType < ActiveRecord::Type::Integer
      #     def cast(value)
      #       if !value.kind_of?(Numeric) && value.include?('$')
      #         price_in_dollars = value.gsub(/\$/, '').to_f
      #         super(price_in_dollars * 100)
      #       else
      #         super
      #       end
      #     end
      #   end
      #
      #   # config/initializers/types.rb
      #   ActiveRecord::Type.register(:money, MoneyType)
      #
      #   # app/models/store_listing.rb
      #   class StoreListing < ActiveRecord::Base
      #     attribute :price_in_cents, :money
      #   end
      #
      #   store_listing = StoreListing.new(price_in_cents: '$10.00')
      #   store_listing.price_in_cents # => 1000
      #
      # For more details on creating custom types, see the documentation for
      # ActiveModel::Type::Value. For more details on registering your types
      # to be referenced by a symbol, see ActiveRecord::Type.register. You can
      # also pass a type object directly, in place of a symbol.
      #
      # ==== \Querying
      #
      # When {ActiveRecord::Base.where}[rdoc-ref:QueryMethods#where] is called, it will
      # use the type defined by the model class to convert the value to SQL,
      # calling +serialize+ on your type object. For example:
      #
      #   class Money < Struct.new(:amount, :currency)
      #   end
      #
      #   class MoneyType < ActiveRecord::Type::Value
      #     def initialize(currency_converter:)
      #       @currency_converter = currency_converter
      #     end
      #
      #     # value will be the result of +deserialize+ or
      #     # +cast+. Assumed to be an instance of +Money+ in
      #     # this case.
      #     def serialize(value)
      #       value_in_bitcoins = @currency_converter.convert_to_bitcoins(value)
      #       value_in_bitcoins.amount
      #     end
      #   end
      #
      #   # config/initializers/types.rb
      #   ActiveRecord::Type.register(:money, MoneyType)
      #
      #   # app/models/product.rb
      #   class Product < ActiveRecord::Base
      #     currency_converter = ConversionRatesFromTheInternet.new
      #     attribute :price_in_bitcoins, :money, currency_converter: currency_converter
      #   end
      #
      #   Product.where(price_in_bitcoins: Money.new(5, "USD"))
      #   # => SELECT * FROM products WHERE price_in_bitcoins = 0.02230
      #
      #   Product.where(price_in_bitcoins: Money.new(5, "GBP"))
      #   # => SELECT * FROM products WHERE price_in_bitcoins = 0.03412
      #
      # ==== Dirty Tracking
      #
      # The type of an attribute is given the opportunity to change how dirty
      # tracking is performed. The methods +changed?+ and +changed_in_place?+
      # will be called from ActiveModel::Dirty. See the documentation for those
      # methods in ActiveModel::Type::Value for more details.
      def attribute(name, cast_type = nil, default: NO_DEFAULT_PROVIDED, **options)
        name = name.to_s
        name = attribute_aliases[name] || name

        reload_schema_from_cache

        case cast_type
        when Symbol
          cast_type = Type.lookup(cast_type, **options, adapter: Type.adapter_name_from(self))
        when nil
          if (prev_cast_type, prev_default = attributes_to_define_after_schema_loads[name])
            default = prev_default if default == NO_DEFAULT_PROVIDED
          else
            prev_cast_type = -> subtype { subtype }
          end

          cast_type = if block_given?
            -> subtype { yield Proc === prev_cast_type ? prev_cast_type[subtype] : prev_cast_type }
          else
            prev_cast_type
          end
        end

        self.attributes_to_define_after_schema_loads =
          attributes_to_define_after_schema_loads.merge(name => [cast_type, default])
      end

      # This is the low level API which sits beneath +attribute+. It only
      # accepts type objects, and will do its work immediately instead of
      # waiting for the schema to load. Automatic schema detection and
      # ClassMethods#attribute both call this under the hood. While this method
      # is provided so it can be used by plugin authors, application code
      # should probably use ClassMethods#attribute.
      #
      # +name+ The name of the attribute being defined. Expected to be a +String+.
      #
      # +cast_type+ The type object to use for this attribute.
      #
      # +default+ The default value to use when no value is provided. If this option
      # is not passed, the previous default value (if any) will be used.
      # Otherwise, the default will be +nil+. A proc can also be passed, and
      # will be called once each time a new value is needed.
      #
      # +user_provided_default+ Whether the default value should be cast using
      # +cast+ or +deserialize+.
      def define_attribute(
        name,
        cast_type,
        default: NO_DEFAULT_PROVIDED,
        user_provided_default: true
      )
        attribute_types[name] = cast_type
        define_default_attribute(name, default, cast_type, from_user: user_provided_default)
      end

      def load_schema! # :nodoc:
        super
        attributes_to_define_after_schema_loads.each do |name, (cast_type, default)|
          cast_type = cast_type[type_for_attribute(name)] if Proc === cast_type
          define_attribute(name, cast_type, default: default)
        end
      end

      private
        NO_DEFAULT_PROVIDED = Object.new # :nodoc:
        private_constant :NO_DEFAULT_PROVIDED

        def define_default_attribute(name, value, type, from_user:)
          if value == NO_DEFAULT_PROVIDED
            default_attribute = _default_attributes[name].with_type(type)
          elsif from_user
            default_attribute = ActiveModel::Attribute::UserProvidedDefault.new(
              name,
              value,
              type,
              _default_attributes.fetch(name.to_s) { nil },
            )
          else
            default_attribute = ActiveModel::Attribute.from_database(name, value, type)
          end
          _default_attributes[name] = default_attribute
        end
    end
  end
end

autosave_association.rb

# frozen_string_literal: true

module ActiveRecord
  # = Active Record Autosave Association
  #
  # AutosaveAssociation is a module that takes care of automatically saving
  # associated records when their parent is saved. In addition to saving, it
  # also destroys any associated records that were marked for destruction.
  # (See #mark_for_destruction and #marked_for_destruction?).
  #
  # Saving of the parent, its associations, and the destruction of marked
  # associations, all happen inside a transaction. This should never leave the
  # database in an inconsistent state.
  #
  # If validations for any of the associations fail, their error messages will
  # be applied to the parent.
  #
  # Note that it also means that associations marked for destruction won't
  # be destroyed directly. They will however still be marked for destruction.
  #
  # Note that <tt>autosave: false</tt> is not same as not declaring <tt>:autosave</tt>.
  # When the <tt>:autosave</tt> option is not present then new association records are
  # saved but the updated association records are not saved.
  #
  # == Validation
  #
  # Child records are validated unless <tt>:validate</tt> is +false+.
  #
  # == Callbacks
  #
  # Association with autosave option defines several callbacks on your
  # model (around_save, before_save, after_create, after_update). Please note that
  # callbacks are executed in the order they were defined in
  # model. You should avoid modifying the association content before
  # autosave callbacks are executed. Placing your callbacks after
  # associations is usually a good practice.
  #
  # === One-to-one Example
  #
  #   class Post < ActiveRecord::Base
  #     has_one :author, autosave: true
  #   end
  #
  # Saving changes to the parent and its associated model can now be performed
  # automatically _and_ atomically:
  #
  #   post = Post.find(1)
  #   post.title       # => "The current global position of migrating ducks"
  #   post.author.name # => "alloy"
  #
  #   post.title = "On the migration of ducks"
  #   post.author.name = "Eloy Duran"
  #
  #   post.save
  #   post.reload
  #   post.title       # => "On the migration of ducks"
  #   post.author.name # => "Eloy Duran"
  #
  # Destroying an associated model, as part of the parent's save action, is as
  # simple as marking it for destruction:
  #
  #   post.author.mark_for_destruction
  #   post.author.marked_for_destruction? # => true
  #
  # Note that the model is _not_ yet removed from the database:
  #
  #   id = post.author.id
  #   Author.find_by(id: id).nil? # => false
  #
  #   post.save
  #   post.reload.author # => nil
  #
  # Now it _is_ removed from the database:
  #
  #   Author.find_by(id: id).nil? # => true
  #
  # === One-to-many Example
  #
  # When <tt>:autosave</tt> is not declared new children are saved when their parent is saved:
  #
  #   class Post < ActiveRecord::Base
  #     has_many :comments # :autosave option is not declared
  #   end
  #
  #   post = Post.new(title: 'ruby rocks')
  #   post.comments.build(body: 'hello world')
  #   post.save # => saves both post and comment
  #
  #   post = Post.create(title: 'ruby rocks')
  #   post.comments.build(body: 'hello world')
  #   post.save # => saves both post and comment
  #
  #   post = Post.create(title: 'ruby rocks')
  #   comment = post.comments.create(body: 'hello world')
  #   comment.body = 'hi everyone'
  #   post.save # => saves post, but not comment
  #
  # When <tt>:autosave</tt> is true all children are saved, no matter whether they
  # are new records or not:
  #
  #   class Post < ActiveRecord::Base
  #     has_many :comments, autosave: true
  #   end
  #
  #   post = Post.create(title: 'ruby rocks')
  #   comment = post.comments.create(body: 'hello world')
  #   comment.body = 'hi everyone'
  #   post.comments.build(body: "good morning.")
  #   post.save # => saves post and both comments.
  #
  # Destroying one of the associated models as part of the parent's save action
  # is as simple as marking it for destruction:
  #
  #   post.comments # => [#<Comment id: 1, ...>, #<Comment id: 2, ...]>
  #   post.comments[1].mark_for_destruction
  #   post.comments[1].marked_for_destruction? # => true
  #   post.comments.length # => 2
  #
  # Note that the model is _not_ yet removed from the database:
  #
  #   id = post.comments.last.id
  #   Comment.find_by(id: id).nil? # => false
  #
  #   post.save
  #   post.reload.comments.length # => 1
  #
  # Now it _is_ removed from the database:
  #
  #   Comment.find_by(id: id).nil? # => true
  #
  # === Caveats
  #
  # Note that autosave will only trigger for already-persisted association records
  # if the records themselves have been changed. This is to protect against
  # <tt>SystemStackError</tt> caused by circular association validations. The one
  # exception is if a custom validation context is used, in which case the validations
  # will always fire on the associated records.
  module AutosaveAssociation
    extend ActiveSupport::Concern

    module AssociationBuilderExtension # :nodoc:
      def self.build(model, reflection)
        model.send(:add_autosave_association_callbacks, reflection)
      end

      def self.valid_options
        [ :autosave ]
      end
    end

    included do
      Associations::Builder::Association.extensions << AssociationBuilderExtension
    end

    module ClassMethods # :nodoc:
      private
        def define_non_cyclic_method(name, &block)
          return if method_defined?(name, false)

          define_method(name) do |*args|
            result = true; @_already_called ||= {}
            # Loop prevention for validation of associations
            unless @_already_called[name]
              begin
                @_already_called[name] = true
                result = instance_eval(&block)
              ensure
                @_already_called[name] = false
              end
            end

            result
          end
        end

        # Adds validation and save callbacks for the association as specified by
        # the +reflection+.
        #
        # For performance reasons, we don't check whether to validate at runtime.
        # However the validation and callback methods are lazy and those methods
        # get created when they are invoked for the very first time. However,
        # this can change, for instance, when using nested attributes, which is
        # called _after_ the association has been defined. Since we don't want
        # the callbacks to get defined multiple times, there are guards that
        # check if the save or validation methods have already been defined
        # before actually defining them.
        def add_autosave_association_callbacks(reflection)
          save_method = :"autosave_associated_records_for_#{reflection.name}"

          if reflection.collection?
            around_save :around_save_collection_association

            define_non_cyclic_method(save_method) { save_collection_association(reflection) }
            # Doesn't use after_save as that would save associations added in after_create/after_update twice
            after_create save_method
            after_update save_method
          elsif reflection.has_one?
            define_non_cyclic_method(save_method) { save_has_one_association(reflection) }
            # Configures two callbacks instead of a single after_save so that
            # the model may rely on their execution order relative to its
            # own callbacks.
            #
            # For example, given that after_creates run before after_saves, if
            # we configured instead an after_save there would be no way to fire
            # a custom after_create callback after the child association gets
            # created.
            after_create save_method
            after_update save_method
          else
            define_non_cyclic_method(save_method) { throw(:abort) if save_belongs_to_association(reflection) == false }
            before_save save_method
          end

          define_autosave_validation_callbacks(reflection)
        end

        def define_autosave_validation_callbacks(reflection)
          validation_method = :"validate_associated_records_for_#{reflection.name}"
          if reflection.validate? && !method_defined?(validation_method)
            if reflection.collection?
              method = :validate_collection_association
            else
              method = :validate_single_association
            end

            define_non_cyclic_method(validation_method) { send(method, reflection) }
            validate validation_method
            after_validation :_ensure_no_duplicate_errors
          end
        end
    end

    # Reloads the attributes of the object as usual and clears <tt>marked_for_destruction</tt> flag.
    def reload(options = nil)
      @marked_for_destruction = false
      @destroyed_by_association = nil
      super
    end

    # Marks this record to be destroyed as part of the parent's save transaction.
    # This does _not_ actually destroy the record instantly, rather child record will be destroyed
    # when <tt>parent.save</tt> is called.
    #
    # Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
    def mark_for_destruction
      @marked_for_destruction = true
    end

    # Returns whether or not this record will be destroyed as part of the parent's save transaction.
    #
    # Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
    def marked_for_destruction?
      @marked_for_destruction
    end

    # Records the association that is being destroyed and destroying this
    # record in the process.
    def destroyed_by_association=(reflection)
      @destroyed_by_association = reflection
    end

    # Returns the association for the parent being destroyed.
    #
    # Used to avoid updating the counter cache unnecessarily.
    def destroyed_by_association
      @destroyed_by_association
    end

    # Returns whether or not this record has been changed in any way (including whether
    # any of its nested autosave associations are likewise changed)
    def changed_for_autosave?
      new_record? || has_changes_to_save? || marked_for_destruction? || nested_records_changed_for_autosave?
    end

    private
      # Returns the record for an association collection that should be validated
      # or saved. If +autosave+ is +false+ only new records will be returned,
      # unless the parent is/was a new record itself.
      def associated_records_to_validate_or_save(association, new_record, autosave)
        if new_record || custom_validation_context?
          association && association.target
        elsif autosave
          association.target.find_all(&:changed_for_autosave?)
        else
          association.target.find_all(&:new_record?)
        end
      end

      # Go through nested autosave associations that are loaded in memory (without loading
      # any new ones), and return true if any are changed for autosave.
      # Returns false if already called to prevent an infinite loop.
      def nested_records_changed_for_autosave?
        @_nested_records_changed_for_autosave_already_called ||= false
        return false if @_nested_records_changed_for_autosave_already_called
        begin
          @_nested_records_changed_for_autosave_already_called = true
          self.class._reflections.values.any? do |reflection|
            if reflection.options[:autosave]
              association = association_instance_get(reflection.name)
              association && Array.wrap(association.target).any?(&:changed_for_autosave?)
            end
          end
        ensure
          @_nested_records_changed_for_autosave_already_called = false
        end
      end

      # Validate the association if <tt>:validate</tt> or <tt>:autosave</tt> is
      # turned on for the association.
      def validate_single_association(reflection)
        association = association_instance_get(reflection.name)
        record      = association && association.reader
        association_valid?(reflection, record) if record && (record.changed_for_autosave? || custom_validation_context?)
      end

      # Validate the associated records if <tt>:validate</tt> or
      # <tt>:autosave</tt> is turned on for the association specified by
      # +reflection+.
      def validate_collection_association(reflection)
        if association = association_instance_get(reflection.name)
          if records = associated_records_to_validate_or_save(association, new_record?, reflection.options[:autosave])
            records.each_with_index { |record, index| association_valid?(reflection, record, index) }
          end
        end
      end

      # Returns whether or not the association is valid and applies any errors to
      # the parent, <tt>self</tt>, if it wasn't. Skips any <tt>:autosave</tt>
      # enabled records if they're marked_for_destruction? or destroyed.
      def association_valid?(reflection, record, index = nil)
        return true if record.destroyed? || (reflection.options[:autosave] && record.marked_for_destruction?)

        context = validation_context if custom_validation_context?

        unless valid = record.valid?(context)
          if reflection.options[:autosave]
            indexed_attribute = !index.nil? && (reflection.options[:index_errors] || ActiveRecord.index_nested_attribute_errors)

            record.errors.group_by_attribute.each { |attribute, errors|
              attribute = normalize_reflection_attribute(indexed_attribute, reflection, index, attribute)

              errors.each { |error|
                self.errors.import(
                  error,
                  attribute: attribute
                )
              }
            }
          else
            errors.add(reflection.name)
          end
        end
        valid
      end

      def normalize_reflection_attribute(indexed_attribute, reflection, index, attribute)
        if indexed_attribute
          "#{reflection.name}[#{index}].#{attribute}"
        else
          "#{reflection.name}.#{attribute}"
        end
      end

      # Is used as an around_save callback to check while saving a collection
      # association whether or not the parent was a new record before saving.
      def around_save_collection_association
        previously_new_record_before_save = (@new_record_before_save ||= false)
        @new_record_before_save = !previously_new_record_before_save && new_record?

        yield
      ensure
        @new_record_before_save = previously_new_record_before_save
      end

      # Saves any new associated records, or all loaded autosave associations if
      # <tt>:autosave</tt> is enabled on the association.
      #
      # In addition, it destroys all children that were marked for destruction
      # with #mark_for_destruction.
      #
      # This all happens inside a transaction, _if_ the Transactions module is included into
      # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
      def save_collection_association(reflection)
        if association = association_instance_get(reflection.name)
          autosave = reflection.options[:autosave]

          # By saving the instance variable in a local variable,
          # we make the whole callback re-entrant.
          new_record_before_save = @new_record_before_save

          # reconstruct the scope now that we know the owner's id
          association.reset_scope

          if records = associated_records_to_validate_or_save(association, new_record_before_save, autosave)
            if autosave
              records_to_destroy = records.select(&:marked_for_destruction?)
              records_to_destroy.each { |record| association.destroy(record) }
              records -= records_to_destroy
            end

            records.each do |record|
              next if record.destroyed?

              saved = true

              if autosave != false && (new_record_before_save || record.new_record?)
                association.set_inverse_instance(record)

                if autosave
                  saved = association.insert_record(record, false)
                elsif !reflection.nested?
                  association_saved = association.insert_record(record)

                  if reflection.validate?
                    errors.add(reflection.name) unless association_saved
                    saved = association_saved
                  end
                end
              elsif autosave
                saved = record.save(validate: false)
              end

              raise(RecordInvalid.new(association.owner)) unless saved
            end
          end
        end
      end

      # Saves the associated record if it's new or <tt>:autosave</tt> is enabled
      # on the association.
      #
      # In addition, it will destroy the association if it was marked for
      # destruction with #mark_for_destruction.
      #
      # This all happens inside a transaction, _if_ the Transactions module is included into
      # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
      def save_has_one_association(reflection)
        association = association_instance_get(reflection.name)
        record      = association && association.load_target

        if record && !record.destroyed?
          autosave = reflection.options[:autosave]

          if autosave && record.marked_for_destruction?
            record.destroy
          elsif autosave != false
            key = reflection.options[:primary_key] ? public_send(reflection.options[:primary_key]) : id

            if (autosave && record.changed_for_autosave?) || _record_changed?(reflection, record, key)
              unless reflection.through_reflection
                record[reflection.foreign_key] = key
                association.set_inverse_instance(record)
              end

              saved = record.save(validate: !autosave)
              raise ActiveRecord::Rollback if !saved && autosave
              saved
            end
          end
        end
      end

      # If the record is new or it has changed, returns true.
      def _record_changed?(reflection, record, key)
        record.new_record? ||
          association_foreign_key_changed?(reflection, record, key) ||
          record.will_save_change_to_attribute?(reflection.foreign_key)
      end

      def association_foreign_key_changed?(reflection, record, key)
        return false if reflection.through_reflection?

        record._has_attribute?(reflection.foreign_key) && record._read_attribute(reflection.foreign_key) != key
      end

      # Saves the associated record if it's new or <tt>:autosave</tt> is enabled.
      #
      # In addition, it will destroy the association if it was marked for destruction.
      def save_belongs_to_association(reflection)
        association = association_instance_get(reflection.name)
        return unless association && association.loaded? && !association.stale_target?

        record = association.load_target
        if record && !record.destroyed?
          autosave = reflection.options[:autosave]

          if autosave && record.marked_for_destruction?
            self[reflection.foreign_key] = nil
            record.destroy
          elsif autosave != false
            saved = record.save(validate: !autosave) if record.new_record? || (autosave && record.changed_for_autosave?)

            if association.updated?
              association_id = record.public_send(reflection.options[:primary_key] || :id)
              self[reflection.foreign_key] = association_id
              association.loaded!
            end

            saved if autosave
          end
        end
      end

      def custom_validation_context?
        validation_context && [:create, :update].exclude?(validation_context)
      end

      def _ensure_no_duplicate_errors
        errors.uniq!
      end
  end
end

base.rb

# frozen_string_literal: true

require "active_support/benchmarkable"
require "active_support/dependencies"
require "active_support/descendants_tracker"
require "active_support/time"
require "active_support/core_ext/class/subclasses"
require "active_record/log_subscriber"
require "active_record/explain_subscriber"
require "active_record/relation/delegation"
require "active_record/attributes"
require "active_record/type_caster"
require "active_record/database_configurations"

module ActiveRecord # :nodoc:
  # = Active Record
  #
  # Active Record objects don't specify their attributes directly, but rather infer them from
  # the table definition with which they're linked. Adding, removing, and changing attributes
  # and their type is done directly in the database. Any change is instantly reflected in the
  # Active Record objects. The mapping that binds a given Active Record class to a certain
  # database table will happen automatically in most common cases, but can be overwritten for the uncommon ones.
  #
  # See the mapping rules in table_name and the full example in link:files/activerecord/README_rdoc.html for more insight.
  #
  # == Creation
  #
  # Active Records accept constructor parameters either in a hash or as a block. The hash
  # method is especially useful when you're receiving the data from somewhere else, like an
  # HTTP request. It works like this:
  #
  #   user = User.new(name: "David", occupation: "Code Artist")
  #   user.name # => "David"
  #
  # You can also use block initialization:
  #
  #   user = User.new do |u|
  #     u.name = "David"
  #     u.occupation = "Code Artist"
  #   end
  #
  # And of course you can just create a bare object and specify the attributes after the fact:
  #
  #   user = User.new
  #   user.name = "David"
  #   user.occupation = "Code Artist"
  #
  # == Conditions
  #
  # Conditions can either be specified as a string, array, or hash representing the WHERE-part of an SQL statement.
  # The array form is to be used when the condition input is tainted and requires sanitization. The string form can
  # be used for statements that don't involve tainted data. The hash form works much like the array form, except
  # only equality and range is possible. Examples:
  #
  #   class User < ActiveRecord::Base
  #     def self.authenticate_unsafely(user_name, password)
  #       where("user_name = '#{user_name}' AND password = '#{password}'").first
  #     end
  #
  #     def self.authenticate_safely(user_name, password)
  #       where("user_name = ? AND password = ?", user_name, password).first
  #     end
  #
  #     def self.authenticate_safely_simply(user_name, password)
  #       where(user_name: user_name, password: password).first
  #     end
  #   end
  #
  # The <tt>authenticate_unsafely</tt> method inserts the parameters directly into the query
  # and is thus susceptible to SQL-injection attacks if the <tt>user_name</tt> and +password+
  # parameters come directly from an HTTP request. The <tt>authenticate_safely</tt> and
  # <tt>authenticate_safely_simply</tt> both will sanitize the <tt>user_name</tt> and +password+
  # before inserting them in the query, which will ensure that an attacker can't escape the
  # query and fake the login (or worse).
  #
  # When using multiple parameters in the conditions, it can easily become hard to read exactly
  # what the fourth or fifth question mark is supposed to represent. In those cases, you can
  # resort to named bind variables instead. That's done by replacing the question marks with
  # symbols and supplying a hash with values for the matching symbol keys:
  #
  #   Company.where(
  #     "id = :id AND name = :name AND division = :division AND created_at > :accounting_date",
  #     { id: 3, name: "37signals", division: "First", accounting_date: '2005-01-01' }
  #   ).first
  #
  # Similarly, a simple hash without a statement will generate conditions based on equality with the SQL AND
  # operator. For instance:
  #
  #   Student.where(first_name: "Harvey", status: 1)
  #   Student.where(params[:student])
  #
  # A range may be used in the hash to use the SQL BETWEEN operator:
  #
  #   Student.where(grade: 9..12)
  #
  # An array may be used in the hash to use the SQL IN operator:
  #
  #   Student.where(grade: [9,11,12])
  #
  # When joining tables, nested hashes or keys written in the form 'table_name.column_name'
  # can be used to qualify the table name of a particular condition. For instance:
  #
  #   Student.joins(:schools).where(schools: { category: 'public' })
  #   Student.joins(:schools).where('schools.category' => 'public' )
  #
  # == Overwriting default accessors
  #
  # All column values are automatically available through basic accessors on the Active Record
  # object, but sometimes you want to specialize this behavior. This can be done by overwriting
  # the default accessors (using the same name as the attribute) and calling
  # +super+ to actually change things.
  #
  #   class Song < ActiveRecord::Base
  #     # Uses an integer of seconds to hold the length of the song
  #
  #     def length=(minutes)
  #       super(minutes.to_i * 60)
  #     end
  #
  #     def length
  #       super / 60
  #     end
  #   end
  #
  # == Attribute query methods
  #
  # In addition to the basic accessors, query methods are also automatically available on the Active Record object.
  # Query methods allow you to test whether an attribute value is present.
  # Additionally, when dealing with numeric values, a query method will return false if the value is zero.
  #
  # For example, an Active Record User with the <tt>name</tt> attribute has a <tt>name?</tt> method that you can call
  # to determine whether the user has a name:
  #
  #   user = User.new(name: "David")
  #   user.name? # => true
  #
  #   anonymous = User.new(name: "")
  #   anonymous.name? # => false
  #
  # Query methods will also respect any overrides of default accessors:
  #
  #   class User
  #     # Has admin boolean column
  #     def admin
  #       false
  #     end
  #   end
  #
  #   user.update(admin: true)
  #
  #   user.read_attribute(:admin)  # => true, gets the column value
  #   user[:admin] # => true, also gets the column value
  #
  #   user.admin   # => false, due to the getter override
  #   user.admin?  # => false, due to the getter override
  #
  # == Accessing attributes before they have been typecasted
  #
  # Sometimes you want to be able to read the raw attribute data without having the column-determined
  # typecast run its course first. That can be done by using the <tt><attribute>_before_type_cast</tt>
  # accessors that all attributes have. For example, if your Account model has a <tt>balance</tt> attribute,
  # you can call <tt>account.balance_before_type_cast</tt> or <tt>account.id_before_type_cast</tt>.
  #
  # This is especially useful in validation situations where the user might supply a string for an
  # integer field and you want to display the original string back in an error message. Accessing the
  # attribute normally would typecast the string to 0, which isn't what you want.
  #
  # == Dynamic attribute-based finders
  #
  # Dynamic attribute-based finders are a mildly deprecated way of getting (and/or creating) objects
  # by simple queries without turning to SQL. They work by appending the name of an attribute
  # to <tt>find_by_</tt> like <tt>Person.find_by_user_name</tt>.
  # Instead of writing <tt>Person.find_by(user_name: user_name)</tt>, you can use
  # <tt>Person.find_by_user_name(user_name)</tt>.
  #
  # It's possible to add an exclamation point (!) on the end of the dynamic finders to get them to raise an
  # ActiveRecord::RecordNotFound error if they do not return any records,
  # like <tt>Person.find_by_last_name!</tt>.
  #
  # It's also possible to use multiple attributes in the same <tt>find_by_</tt> by separating them with
  # "_and_".
  #
  #  Person.find_by(user_name: user_name, password: password)
  #  Person.find_by_user_name_and_password(user_name, password) # with dynamic finder
  #
  # It's even possible to call these dynamic finder methods on relations and named scopes.
  #
  #   Payment.order("created_on").find_by_amount(50)
  #
  # == Saving arrays, hashes, and other non-mappable objects in text columns
  #
  # Active Record can serialize any object in text columns using YAML. To do so, you must
  # specify this with a call to the class method
  # {serialize}[rdoc-ref:AttributeMethods::Serialization::ClassMethods#serialize].
  # This makes it possible to store arrays, hashes, and other non-mappable objects without doing
  # any additional work.
  #
  #   class User < ActiveRecord::Base
  #     serialize :preferences
  #   end
  #
  #   user = User.create(preferences: { "background" => "black", "display" => large })
  #   User.find(user.id).preferences # => { "background" => "black", "display" => large }
  #
  # You can also specify a class option as the second parameter that'll raise an exception
  # if a serialized object is retrieved as a descendant of a class not in the hierarchy.
  #
  #   class User < ActiveRecord::Base
  #     serialize :preferences, Hash
  #   end
  #
  #   user = User.create(preferences: %w( one two three ))
  #   User.find(user.id).preferences    # raises SerializationTypeMismatch
  #
  # When you specify a class option, the default value for that attribute will be a new
  # instance of that class.
  #
  #   class User < ActiveRecord::Base
  #     serialize :preferences, OpenStruct
  #   end
  #
  #   user = User.new
  #   user.preferences.theme_color = "red"
  #
  #
  # == Single table inheritance
  #
  # Active Record allows inheritance by storing the name of the class in a
  # column that is named "type" by default. See ActiveRecord::Inheritance for
  # more details.
  #
  # == Connection to multiple databases in different models
  #
  # Connections are usually created through
  # {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection] and retrieved
  # by ActiveRecord::Base.connection. All classes inheriting from ActiveRecord::Base will use this
  # connection. But you can also set a class-specific connection. For example, if Course is an
  # ActiveRecord::Base, but resides in a different database, you can just say <tt>Course.establish_connection</tt>
  # and Course and all of its subclasses will use this connection instead.
  #
  # This feature is implemented by keeping a connection pool in ActiveRecord::Base that is
  # a hash indexed by the class. If a connection is requested, the
  # {ActiveRecord::Base.retrieve_connection}[rdoc-ref:ConnectionHandling#retrieve_connection] method
  # will go up the class-hierarchy until a connection is found in the connection pool.
  #
  # == Exceptions
  #
  # * ActiveRecordError - Generic error class and superclass of all other errors raised by Active Record.
  # * AdapterNotSpecified - The configuration hash used in
  #   {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection]
  #   didn't include an <tt>:adapter</tt> key.
  # * AdapterNotFound - The <tt>:adapter</tt> key used in
  #   {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection]
  #   specified a non-existent adapter
  #   (or a bad spelling of an existing one).
  # * AssociationTypeMismatch - The object assigned to the association wasn't of the type
  #   specified in the association definition.
  # * AttributeAssignmentError - An error occurred while doing a mass assignment through the
  #   {ActiveRecord::Base#attributes=}[rdoc-ref:AttributeAssignment#attributes=] method.
  #   You can inspect the +attribute+ property of the exception object to determine which attribute
  #   triggered the error.
  # * ConnectionNotEstablished - No connection has been established.
  #   Use {ActiveRecord::Base.establish_connection}[rdoc-ref:ConnectionHandling#establish_connection] before querying.
  # * MultiparameterAssignmentErrors - Collection of errors that occurred during a mass assignment using the
  #   {ActiveRecord::Base#attributes=}[rdoc-ref:AttributeAssignment#attributes=] method.
  #   The +errors+ property of this exception contains an array of
  #   AttributeAssignmentError
  #   objects that should be inspected to determine which attributes triggered the errors.
  # * RecordInvalid - raised by {ActiveRecord::Base#save!}[rdoc-ref:Persistence#save!] and
  #   {ActiveRecord::Base.create!}[rdoc-ref:Persistence::ClassMethods#create!]
  #   when the record is invalid.
  # * RecordNotFound - No record responded to the {ActiveRecord::Base.find}[rdoc-ref:FinderMethods#find] method.
  #   Either the row with the given ID doesn't exist or the row didn't meet the additional restrictions.
  #   Some {ActiveRecord::Base.find}[rdoc-ref:FinderMethods#find] calls do not raise this exception to signal
  #   nothing was found, please check its documentation for further details.
  # * SerializationTypeMismatch - The serialized object wasn't of the class specified as the second parameter.
  # * StatementInvalid - The database server rejected the SQL statement. The precise error is added in the message.
  #
  # *Note*: The attributes listed are class-level attributes (accessible from both the class and instance level).
  # So it's possible to assign a logger to the class through <tt>Base.logger=</tt> which will then be used by all
  # instances in the current object space.
  class Base
    extend ActiveModel::Naming

    extend ActiveSupport::Benchmarkable
    extend ActiveSupport::DescendantsTracker

    extend ConnectionHandling
    extend QueryCache::ClassMethods
    extend Querying
    extend Translation
    extend DynamicMatchers
    extend DelegatedType
    extend Explain
    extend Enum
    extend Delegation::DelegateCache
    extend Aggregations::ClassMethods

    include Core
    include Persistence
    include ReadonlyAttributes
    include ModelSchema
    include Inheritance
    include Scoping
    include Sanitization
    include AttributeAssignment
    include ActiveModel::Conversion
    include Integration
    include Validations
    include CounterCache
    include Attributes
    include Locking::Optimistic
    include Locking::Pessimistic
    include AttributeMethods
    include Callbacks
    include Timestamp
    include Associations
    include SecurePassword
    include AutosaveAssociation
    include NestedAttributes
    include Transactions
    include TouchLater
    include NoTouching
    include Reflection
    include Serialization
    include Store
    include SecureToken
    include SignedId
    include Suppressor
    include Encryption::EncryptableRecord
  end

  ActiveSupport.run_load_hooks(:active_record, Base)
end

basic_object_handler.rb

# frozen_string_literal: true

module ActiveRecord
  class PredicateBuilder
    class BasicObjectHandler # :nodoc:
      def initialize(predicate_builder)
        @predicate_builder = predicate_builder
      end

      def call(attribute, value)
        bind = predicate_builder.build_bind_attribute(attribute.name, value)
        attribute.eq(bind)
      end

      private
        attr_reader :predicate_builder
    end
  end
end

batch.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class Preloader
      class Batch # :nodoc:
        def initialize(preloaders, available_records:)
          @preloaders = preloaders.reject(&:empty?)
          @available_records = available_records.flatten.group_by { |r| r.class.base_class }
        end

        def call
          branches = @preloaders.flat_map(&:branches)
          until branches.empty?
            loaders = branches.flat_map(&:runnable_loaders)

            loaders.each { |loader| loader.associate_records_from_unscoped(@available_records[loader.klass.base_class]) }

            if loaders.any?
              future_tables = branches.flat_map do |branch|
                branch.future_classes - branch.runnable_loaders.map(&:klass)
              end.map(&:table_name).uniq

              target_loaders = loaders.reject { |l| future_tables.include?(l.table_name)  }
              target_loaders = loaders if target_loaders.empty?

              group_and_load_similar(target_loaders)
              target_loaders.each(&:run)
            end

            finished, in_progress = branches.partition(&:done?)

            branches = in_progress + finished.flat_map(&:children)
          end
        end

        private
          attr_reader :loaders

          def group_and_load_similar(loaders)
            loaders.grep_v(ThroughAssociation).group_by(&:loader_query).each_pair do |query, similar_loaders|
              query.load_records_in_batch(similar_loaders)
            end
          end
      end
    end
  end
end

batch_enumerator.rb

# frozen_string_literal: true

module ActiveRecord
  module Batches
    class BatchEnumerator
      include Enumerable

      def initialize(of: 1000, start: nil, finish: nil, relation:) # :nodoc:
        @of       = of
        @relation = relation
        @start = start
        @finish = finish
      end

      # The primary key value from which the BatchEnumerator starts, inclusive of the value.
      attr_reader :start

      # The primary key value at which the BatchEnumerator ends, inclusive of the value.
      attr_reader :finish

      # The relation from which the BatchEnumerator yields batches.
      attr_reader :relation

      # The size of the batches yielded by the BatchEnumerator.
      def batch_size
        @of
      end

      # Looping through a collection of records from the database (using the
      # +all+ method, for example) is very inefficient since it will try to
      # instantiate all the objects at once.
      #
      # In that case, batch processing methods allow you to work with the
      # records in batches, thereby greatly reducing memory consumption.
      #
      #   Person.in_batches.each_record do |person|
      #     person.do_awesome_stuff
      #   end
      #
      #   Person.where("age > 21").in_batches(of: 10).each_record do |person|
      #     person.party_all_night!
      #   end
      #
      # If you do not provide a block to #each_record, it will return an Enumerator
      # for chaining with other methods:
      #
      #   Person.in_batches.each_record.with_index do |person, index|
      #     person.award_trophy(index + 1)
      #   end
      def each_record(&block)
        return to_enum(:each_record) unless block_given?

        @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: true).each do |relation|
          relation.records.each(&block)
        end
      end

      # Deletes records in batches. Returns the total number of rows affected.
      #
      #   Person.in_batches.delete_all
      #
      # See Relation#delete_all for details of how each batch is deleted.
      def delete_all
        sum(&:delete_all)
      end

      # Updates records in batches. Returns the total number of rows affected.
      #
      #   Person.in_batches.update_all("age = age + 1")
      #
      # See Relation#update_all for details of how each batch is updated.
      def update_all(updates)
        sum do |relation|
          relation.update_all(updates)
        end
      end

      # Destroys records in batches.
      #
      #   Person.where("age < 10").in_batches.destroy_all
      #
      # See Relation#destroy_all for details of how each batch is destroyed.
      def destroy_all
        each(&:destroy_all)
      end

      # Yields an ActiveRecord::Relation object for each batch of records.
      #
      #   Person.in_batches.each do |relation|
      #     relation.update_all(awesome: true)
      #   end
      def each(&block)
        enum = @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: false)
        return enum.each(&block) if block_given?
        enum
      end
    end
  end
end

batches.rb

# frozen_string_literal: true

require "active_record/relation/batches/batch_enumerator"

module ActiveRecord
  module Batches
    ORDER_IGNORE_MESSAGE = "Scoped order is ignored, it's forced to be batch order."

    # Looping through a collection of records from the database
    # (using the Scoping::Named::ClassMethods.all method, for example)
    # is very inefficient since it will try to instantiate all the objects at once.
    #
    # In that case, batch processing methods allow you to work
    # with the records in batches, thereby greatly reducing memory consumption.
    #
    # The #find_each method uses #find_in_batches with a batch size of 1000 (or as
    # specified by the +:batch_size+ option).
    #
    #   Person.find_each do |person|
    #     person.do_awesome_stuff
    #   end
    #
    #   Person.where("age > 21").find_each do |person|
    #     person.party_all_night!
    #   end
    #
    # If you do not provide a block to #find_each, it will return an Enumerator
    # for chaining with other methods:
    #
    #   Person.find_each.with_index do |person, index|
    #     person.award_trophy(index + 1)
    #   end
    #
    # ==== Options
    # * <tt>:batch_size</tt> - Specifies the size of the batch. Defaults to 1000.
    # * <tt>:start</tt> - Specifies the primary key value to start from, inclusive of the value.
    # * <tt>:finish</tt> - Specifies the primary key value to end at, inclusive of the value.
    # * <tt>:error_on_ignore</tt> - Overrides the application config to specify if an error should be raised when
    #   an order is present in the relation.
    # * <tt>:order</tt> - Specifies the primary key order (can be +:asc+ or +:desc+). Defaults to +:asc+.
    #
    # Limits are honored, and if present there is no requirement for the batch
    # size: it can be less than, equal to, or greater than the limit.
    #
    # The options +start+ and +finish+ are especially useful if you want
    # multiple workers dealing with the same processing queue. You can make
    # worker 1 handle all the records between id 1 and 9999 and worker 2
    # handle from 10000 and beyond by setting the +:start+ and +:finish+
    # option on each worker.
    #
    #   # In worker 1, let's process until 9999 records.
    #   Person.find_each(finish: 9_999) do |person|
    #     person.party_all_night!
    #   end
    #
    #   # In worker 2, let's process from record 10_000 and onwards.
    #   Person.find_each(start: 10_000) do |person|
    #     person.party_all_night!
    #   end
    #
    # NOTE: Order can be ascending (:asc) or descending (:desc). It is automatically set to
    # ascending on the primary key ("id ASC").
    # This also means that this method only works when the primary key is
    # orderable (e.g. an integer or string).
    #
    # NOTE: By its nature, batch processing is subject to race conditions if
    # other processes are modifying the database.
    def find_each(start: nil, finish: nil, batch_size: 1000, error_on_ignore: nil, order: :asc, &block)
      if block_given?
        find_in_batches(start: start, finish: finish, batch_size: batch_size, error_on_ignore: error_on_ignore, order: order) do |records|
          records.each(&block)
        end
      else
        enum_for(:find_each, start: start, finish: finish, batch_size: batch_size, error_on_ignore: error_on_ignore, order: order) do
          relation = self
          apply_limits(relation, start, finish, order).size
        end
      end
    end

    # Yields each batch of records that was found by the find options as
    # an array.
    #
    #   Person.where("age > 21").find_in_batches do |group|
    #     sleep(50) # Make sure it doesn't get too crowded in there!
    #     group.each { |person| person.party_all_night! }
    #   end
    #
    # If you do not provide a block to #find_in_batches, it will return an Enumerator
    # for chaining with other methods:
    #
    #   Person.find_in_batches.with_index do |group, batch|
    #     puts "Processing group ##{batch}"
    #     group.each(&:recover_from_last_night!)
    #   end
    #
    # To be yielded each record one by one, use #find_each instead.
    #
    # ==== Options
    # * <tt>:batch_size</tt> - Specifies the size of the batch. Defaults to 1000.
    # * <tt>:start</tt> - Specifies the primary key value to start from, inclusive of the value.
    # * <tt>:finish</tt> - Specifies the primary key value to end at, inclusive of the value.
    # * <tt>:error_on_ignore</tt> - Overrides the application config to specify if an error should be raised when
    #   an order is present in the relation.
    # * <tt>:order</tt> - Specifies the primary key order (can be +:asc+ or +:desc+). Defaults to +:asc+.
    #
    # Limits are honored, and if present there is no requirement for the batch
    # size: it can be less than, equal to, or greater than the limit.
    #
    # The options +start+ and +finish+ are especially useful if you want
    # multiple workers dealing with the same processing queue. You can make
    # worker 1 handle all the records between id 1 and 9999 and worker 2
    # handle from 10000 and beyond by setting the +:start+ and +:finish+
    # option on each worker.
    #
    #   # Let's process from record 10_000 on.
    #   Person.find_in_batches(start: 10_000) do |group|
    #     group.each { |person| person.party_all_night! }
    #   end
    #
    # NOTE: Order can be ascending (:asc) or descending (:desc). It is automatically set to
    # ascending on the primary key ("id ASC").
    # This also means that this method only works when the primary key is
    # orderable (e.g. an integer or string).
    #
    # NOTE: By its nature, batch processing is subject to race conditions if
    # other processes are modifying the database.
    def find_in_batches(start: nil, finish: nil, batch_size: 1000, error_on_ignore: nil, order: :asc)
      relation = self
      unless block_given?
        return to_enum(:find_in_batches, start: start, finish: finish, batch_size: batch_size, error_on_ignore: error_on_ignore, order: order) do
          total = apply_limits(relation, start, finish, order).size
          (total - 1).div(batch_size) + 1
        end
      end

      in_batches(of: batch_size, start: start, finish: finish, load: true, error_on_ignore: error_on_ignore, order: order) do |batch|
        yield batch.to_a
      end
    end

    # Yields ActiveRecord::Relation objects to work with a batch of records.
    #
    #   Person.where("age > 21").in_batches do |relation|
    #     relation.delete_all
    #     sleep(10) # Throttle the delete queries
    #   end
    #
    # If you do not provide a block to #in_batches, it will return a
    # BatchEnumerator which is enumerable.
    #
    #   Person.in_batches.each_with_index do |relation, batch_index|
    #     puts "Processing relation ##{batch_index}"
    #     relation.delete_all
    #   end
    #
    # Examples of calling methods on the returned BatchEnumerator object:
    #
    #   Person.in_batches.delete_all
    #   Person.in_batches.update_all(awesome: true)
    #   Person.in_batches.each_record(&:party_all_night!)
    #
    # ==== Options
    # * <tt>:of</tt> - Specifies the size of the batch. Defaults to 1000.
    # * <tt>:load</tt> - Specifies if the relation should be loaded. Defaults to false.
    # * <tt>:start</tt> - Specifies the primary key value to start from, inclusive of the value.
    # * <tt>:finish</tt> - Specifies the primary key value to end at, inclusive of the value.
    # * <tt>:error_on_ignore</tt> - Overrides the application config to specify if an error should be raised when
    #   an order is present in the relation.
    # * <tt>:order</tt> - Specifies the primary key order (can be +:asc+ or +:desc+). Defaults to +:asc+.
    #
    # Limits are honored, and if present there is no requirement for the batch
    # size, it can be less than, equal, or greater than the limit.
    #
    # The options +start+ and +finish+ are especially useful if you want
    # multiple workers dealing with the same processing queue. You can make
    # worker 1 handle all the records between id 1 and 9999 and worker 2
    # handle from 10000 and beyond by setting the +:start+ and +:finish+
    # option on each worker.
    #
    #   # Let's process from record 10_000 on.
    #   Person.in_batches(start: 10_000).update_all(awesome: true)
    #
    # An example of calling where query method on the relation:
    #
    #   Person.in_batches.each do |relation|
    #     relation.update_all('age = age + 1')
    #     relation.where('age > 21').update_all(should_party: true)
    #     relation.where('age <= 21').delete_all
    #   end
    #
    # NOTE: If you are going to iterate through each record, you should call
    # #each_record on the yielded BatchEnumerator:
    #
    #   Person.in_batches.each_record(&:party_all_night!)
    #
    # NOTE: Order can be ascending (:asc) or descending (:desc). It is automatically set to
    # ascending on the primary key ("id ASC").
    # This also means that this method only works when the primary key is
    # orderable (e.g. an integer or string).
    #
    # NOTE: By its nature, batch processing is subject to race conditions if
    # other processes are modifying the database.
    def in_batches(of: 1000, start: nil, finish: nil, load: false, error_on_ignore: nil, order: :asc)
      relation = self
      unless block_given?
        return BatchEnumerator.new(of: of, start: start, finish: finish, relation: self)
      end

      unless [:asc, :desc].include?(order)
        raise ArgumentError, ":order must be :asc or :desc, got #{order.inspect}"
      end

      if arel.orders.present?
        act_on_ignored_order(error_on_ignore)
      end

      batch_limit = of
      if limit_value
        remaining   = limit_value
        batch_limit = remaining if remaining < batch_limit
      end

      relation = relation.reorder(batch_order(order)).limit(batch_limit)
      relation = apply_limits(relation, start, finish, order)
      relation.skip_query_cache! # Retaining the results in the query cache would undermine the point of batching
      batch_relation = relation

      loop do
        if load
          records = batch_relation.records
          ids = records.map(&:id)
          yielded_relation = where(primary_key => ids)
          yielded_relation.load_records(records)
        else
          ids = batch_relation.pluck(primary_key)
          yielded_relation = where(primary_key => ids)
        end

        break if ids.empty?

        primary_key_offset = ids.last
        raise ArgumentError.new("Primary key not included in the custom select clause") unless primary_key_offset

        yield yielded_relation

        break if ids.length < batch_limit

        if limit_value
          remaining -= ids.length

          if remaining == 0
            # Saves a useless iteration when the limit is a multiple of the
            # batch size.
            break
          elsif remaining < batch_limit
            relation = relation.limit(remaining)
          end
        end

        batch_relation = relation.where(
          predicate_builder[primary_key, primary_key_offset, order == :desc ? :lt : :gt]
        )
      end
    end

    private
      def apply_limits(relation, start, finish, order)
        relation = apply_start_limit(relation, start, order) if start
        relation = apply_finish_limit(relation, finish, order) if finish
        relation
      end

      def apply_start_limit(relation, start, order)
        relation.where(predicate_builder[primary_key, start, order == :desc ? :lteq : :gteq])
      end

      def apply_finish_limit(relation, finish, order)
        relation.where(predicate_builder[primary_key, finish, order == :desc ? :gteq : :lteq])
      end

      def batch_order(order)
        table[primary_key].public_send(order)
      end

      def act_on_ignored_order(error_on_ignore)
        raise_error = (error_on_ignore.nil? ? ActiveRecord.error_on_ignored_order : error_on_ignore)

        if raise_error
          raise ArgumentError.new(ORDER_IGNORE_MESSAGE)
        elsif logger
          logger.warn(ORDER_IGNORE_MESSAGE)
        end
      end
  end
end

before_type_cast.rb

# frozen_string_literal: true

module ActiveRecord
  module AttributeMethods
    # = Active Record Attribute Methods Before Type Cast
    #
    # ActiveRecord::AttributeMethods::BeforeTypeCast provides a way to
    # read the value of the attributes before typecasting and deserialization.
    #
    #   class Task < ActiveRecord::Base
    #   end
    #
    #   task = Task.new(id: '1', completed_on: '2012-10-21')
    #   task.id           # => 1
    #   task.completed_on # => Sun, 21 Oct 2012
    #
    #   task.attributes_before_type_cast
    #   # => {"id"=>"1", "completed_on"=>"2012-10-21", ... }
    #   task.read_attribute_before_type_cast('id')           # => "1"
    #   task.read_attribute_before_type_cast('completed_on') # => "2012-10-21"
    #
    # In addition to #read_attribute_before_type_cast and #attributes_before_type_cast,
    # it declares a method for all attributes with the <tt>*_before_type_cast</tt>
    # suffix.
    #
    #   task.id_before_type_cast           # => "1"
    #   task.completed_on_before_type_cast # => "2012-10-21"
    module BeforeTypeCast
      extend ActiveSupport::Concern

      included do
        attribute_method_suffix "_before_type_cast", "_for_database", parameters: false
        attribute_method_suffix "_came_from_user?", parameters: false
      end

      # Returns the value of the attribute identified by +attr_name+ before
      # typecasting and deserialization.
      #
      #   class Task < ActiveRecord::Base
      #   end
      #
      #   task = Task.new(id: '1', completed_on: '2012-10-21')
      #   task.read_attribute('id')                            # => 1
      #   task.read_attribute_before_type_cast('id')           # => '1'
      #   task.read_attribute('completed_on')                  # => Sun, 21 Oct 2012
      #   task.read_attribute_before_type_cast('completed_on') # => "2012-10-21"
      #   task.read_attribute_before_type_cast(:completed_on)  # => "2012-10-21"
      def read_attribute_before_type_cast(attr_name)
        name = attr_name.to_s
        name = self.class.attribute_aliases[name] || name

        attribute_before_type_cast(name)
      end

      # Returns a hash of attributes before typecasting and deserialization.
      #
      #   class Task < ActiveRecord::Base
      #   end
      #
      #   task = Task.new(title: nil, is_done: true, completed_on: '2012-10-21')
      #   task.attributes
      #   # => {"id"=>nil, "title"=>nil, "is_done"=>true, "completed_on"=>Sun, 21 Oct 2012, "created_at"=>nil, "updated_at"=>nil}
      #   task.attributes_before_type_cast
      #   # => {"id"=>nil, "title"=>nil, "is_done"=>true, "completed_on"=>"2012-10-21", "created_at"=>nil, "updated_at"=>nil}
      def attributes_before_type_cast
        @attributes.values_before_type_cast
      end

      # Returns a hash of attributes for assignment to the database.
      def attributes_for_database
        @attributes.values_for_database
      end

      private
        # Dispatch target for <tt>*_before_type_cast</tt> attribute methods.
        def attribute_before_type_cast(attr_name)
          @attributes[attr_name].value_before_type_cast
        end

        def attribute_for_database(attr_name)
          @attributes[attr_name].value_for_database
        end

        def attribute_came_from_user?(attr_name)
          @attributes[attr_name].came_from_user?
        end
    end
  end
end

belongs_to.rb

# frozen_string_literal: true

module ActiveRecord::Associations::Builder # :nodoc:
  class BelongsTo < SingularAssociation # :nodoc:
    def self.macro
      :belongs_to
    end

    def self.valid_options(options)
      valid = super + [:polymorphic, :counter_cache, :optional, :default]
      valid += [:foreign_type] if options[:polymorphic]
      valid += [:ensuring_owner_was] if options[:dependent] == :destroy_async
      valid
    end

    def self.valid_dependent_options
      [:destroy, :delete, :destroy_async]
    end

    def self.define_callbacks(model, reflection)
      super
      add_counter_cache_callbacks(model, reflection) if reflection.options[:counter_cache]
      add_touch_callbacks(model, reflection)         if reflection.options[:touch]
      add_default_callbacks(model, reflection)       if reflection.options[:default]
    end

    def self.add_counter_cache_callbacks(model, reflection)
      cache_column = reflection.counter_cache_column

      model.after_update lambda { |record|
        association = association(reflection.name)

        if association.saved_change_to_target?
          association.increment_counters
          association.decrement_counters_before_last_save
        end
      }

      klass = reflection.class_name.safe_constantize
      klass.attr_readonly cache_column if klass && klass.respond_to?(:attr_readonly)
    end

    def self.touch_record(o, changes, foreign_key, name, touch, touch_method) # :nodoc:
      old_foreign_id = changes[foreign_key] && changes[foreign_key].first

      if old_foreign_id
        association = o.association(name)
        reflection = association.reflection
        if reflection.polymorphic?
          foreign_type = reflection.foreign_type
          klass = changes[foreign_type] && changes[foreign_type].first || o.public_send(foreign_type)
          klass = o.class.polymorphic_class_for(klass)
        else
          klass = association.klass
        end
        primary_key = reflection.association_primary_key(klass)
        old_record = klass.find_by(primary_key => old_foreign_id)

        if old_record
          if touch != true
            old_record.public_send(touch_method, touch)
          else
            old_record.public_send(touch_method)
          end
        end
      end

      record = o.public_send name
      if record && record.persisted?
        if touch != true
          record.public_send(touch_method, touch)
        else
          record.public_send(touch_method)
        end
      end
    end

    def self.add_touch_callbacks(model, reflection)
      foreign_key = reflection.foreign_key
      name        = reflection.name
      touch       = reflection.options[:touch]

      callback = lambda { |changes_method| lambda { |record|
        BelongsTo.touch_record(record, record.send(changes_method), foreign_key, name, touch, belongs_to_touch_method)
      }}

      if reflection.counter_cache_column
        touch_callback = callback.(:saved_changes)
        update_callback = lambda { |record|
          instance_exec(record, &touch_callback) unless association(reflection.name).saved_change_to_target?
        }
        model.after_update update_callback, if: :saved_changes?
      else
        model.after_create callback.(:saved_changes), if: :saved_changes?
        model.after_update callback.(:saved_changes), if: :saved_changes?
        model.after_destroy callback.(:changes_to_save)
      end

      model.after_touch callback.(:changes_to_save)
    end

    def self.add_default_callbacks(model, reflection)
      model.before_validation lambda { |o|
        o.association(reflection.name).default(&reflection.options[:default])
      }
    end

    def self.add_destroy_callbacks(model, reflection)
      model.after_destroy lambda { |o| o.association(reflection.name).handle_dependency }
    end

    def self.define_validations(model, reflection)
      if reflection.options.key?(:required)
        reflection.options[:optional] = !reflection.options.delete(:required)
      end

      if reflection.options[:optional].nil?
        required = model.belongs_to_required_by_default
      else
        required = !reflection.options[:optional]
      end

      super

      if required
        model.validates_presence_of reflection.name, message: :required
      end
    end

    def self.define_change_tracking_methods(model, reflection)
      model.generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
        def #{reflection.name}_changed?
          association(:#{reflection.name}).target_changed?
        end

        def #{reflection.name}_previously_changed?
          association(:#{reflection.name}).target_previously_changed?
        end
      CODE
    end

    private_class_method :macro, :valid_options, :valid_dependent_options, :define_callbacks,
      :define_validations, :define_change_tracking_methods, :add_counter_cache_callbacks,
      :add_touch_callbacks, :add_default_callbacks, :add_destroy_callbacks
  end
end

belongs_to_association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    # = Active Record Belongs To Association
    class BelongsToAssociation < SingularAssociation # :nodoc:
      def handle_dependency
        return unless load_target

        case options[:dependent]
        when :destroy
          raise ActiveRecord::Rollback unless target.destroy
        when :destroy_async
          id = owner.public_send(reflection.foreign_key.to_sym)
          primary_key_column = reflection.active_record_primary_key.to_sym

          enqueue_destroy_association(
            owner_model_name: owner.class.to_s,
            owner_id: owner.id,
            association_class: reflection.klass.to_s,
            association_ids: [id],
            association_primary_key_column: primary_key_column,
            ensuring_owner_was_method: options.fetch(:ensuring_owner_was, nil)
          )
        else
          target.public_send(options[:dependent])
        end
      end

      def inversed_from(record)
        replace_keys(record)
        super
      end

      def default(&block)
        writer(owner.instance_exec(&block)) if reader.nil?
      end

      def reset
        super
        @updated = false
      end

      def updated?
        @updated
      end

      def decrement_counters
        update_counters(-1)
      end

      def increment_counters
        update_counters(1)
      end

      def decrement_counters_before_last_save
        if reflection.polymorphic?
          model_type_was = owner.attribute_before_last_save(reflection.foreign_type)
          model_was = owner.class.polymorphic_class_for(model_type_was) if model_type_was
        else
          model_was = klass
        end

        foreign_key_was = owner.attribute_before_last_save(reflection.foreign_key)

        if foreign_key_was && model_was < ActiveRecord::Base
          update_counters_via_scope(model_was, foreign_key_was, -1)
        end
      end

      def target_changed?
        owner.attribute_changed?(reflection.foreign_key) || (!foreign_key_present? && target&.new_record?)
      end

      def target_previously_changed?
        owner.attribute_previously_changed?(reflection.foreign_key)
      end

      def saved_change_to_target?
        owner.saved_change_to_attribute?(reflection.foreign_key)
      end

      private
        def replace(record)
          if record
            raise_on_type_mismatch!(record)
            set_inverse_instance(record)
            @updated = true
          elsif target
            remove_inverse_instance(target)
          end

          replace_keys(record, force: true)

          self.target = record
        end

        def update_counters(by)
          if require_counter_update? && foreign_key_present?
            if target && !stale_target?
              target.increment!(reflection.counter_cache_column, by, touch: reflection.options[:touch])
            else
              update_counters_via_scope(klass, owner._read_attribute(reflection.foreign_key), by)
            end
          end
        end

        def update_counters_via_scope(klass, foreign_key, by)
          scope = klass.unscoped.where!(primary_key(klass) => foreign_key)
          scope.update_counters(reflection.counter_cache_column => by, touch: reflection.options[:touch])
        end

        def find_target?
          !loaded? && foreign_key_present? && klass
        end

        def require_counter_update?
          reflection.counter_cache_column && owner.persisted?
        end

        def replace_keys(record, force: false)
          target_key = record ? record._read_attribute(primary_key(record.class)) : nil

          if force || owner._read_attribute(reflection.foreign_key) != target_key
            owner[reflection.foreign_key] = target_key
          end
        end

        def primary_key(klass)
          reflection.association_primary_key(klass)
        end

        def foreign_key_present?
          owner._read_attribute(reflection.foreign_key)
        end

        def invertible_for?(record)
          inverse = inverse_reflection_for(record)
          inverse && (inverse.has_one? || inverse.klass.has_many_inversing)
        end

        def stale_state
          result = owner._read_attribute(reflection.foreign_key) { |n| owner.send(:missing_attribute, n, caller) }
          result && result.to_s
        end
    end
  end
end

belongs_to_polymorphic_association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    # = Active Record Belongs To Polymorphic Association
    class BelongsToPolymorphicAssociation < BelongsToAssociation # :nodoc:
      def klass
        type = owner[reflection.foreign_type]
        type.presence && owner.class.polymorphic_class_for(type)
      end

      def target_changed?
        super || owner.attribute_changed?(reflection.foreign_type)
      end

      def target_previously_changed?
        super || owner.attribute_previously_changed?(reflection.foreign_type)
      end

      def saved_change_to_target?
        super || owner.saved_change_to_attribute?(reflection.foreign_type)
      end

      private
        def replace_keys(record, force: false)
          super

          target_type = record ? record.class.polymorphic_name : nil

          if force || owner._read_attribute(reflection.foreign_type) != target_type
            owner[reflection.foreign_type] = target_type
          end
        end

        def inverse_reflection_for(record)
          reflection.polymorphic_inverse_of(record.class)
        end

        def raise_on_type_mismatch!(record)
          # A polymorphic association cannot have a type mismatch, by definition
        end

        def stale_state
          foreign_key = super
          foreign_key && [foreign_key.to_s, owner[reflection.foreign_type].to_s]
        end
    end
  end
end

binary.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Binary < Arel::Nodes::NodeExpression
      attr_accessor :left, :right

      def initialize(left, right)
        super()
        @left  = left
        @right = right
      end

      def initialize_copy(other)
        super
        @left  = @left.clone if @left
        @right = @right.clone if @right
      end

      def hash
        [self.class, @left, @right].hash
      end

      def eql?(other)
        self.class == other.class &&
          self.left == other.left &&
          self.right == other.right
      end
      alias :== :eql?
    end

    module FetchAttribute
      def fetch_attribute
        if left.is_a?(Arel::Attributes::Attribute)
          yield left
        elsif right.is_a?(Arel::Attributes::Attribute)
          yield right
        end
      end
    end

    class Between < Binary; include FetchAttribute; end

    class GreaterThan < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::LessThanOrEqual.new(left, right)
      end
    end

    class GreaterThanOrEqual < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::LessThan.new(left, right)
      end
    end

    class LessThan < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::GreaterThanOrEqual.new(left, right)
      end
    end

    class LessThanOrEqual < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::GreaterThan.new(left, right)
      end
    end

    class IsDistinctFrom < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::IsNotDistinctFrom.new(left, right)
      end
    end

    class IsNotDistinctFrom < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::IsDistinctFrom.new(left, right)
      end
    end

    class NotEqual < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::Equality.new(left, right)
      end
    end

    class NotIn < Binary
      include FetchAttribute

      def invert
        Arel::Nodes::In.new(left, right)
      end
    end

    class Or < Binary
      def fetch_attribute(&block)
        left.fetch_attribute(&block) && right.fetch_attribute(&block)
      end
    end

    %w{
      As
      Assignment
      Join
      Union
      UnionAll
      Intersect
      Except
    }.each do |name|
      const_set name, Class.new(Binary)
    end
  end
end

bind.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Collectors
    class Bind
      def initialize
        @binds = []
      end

      def <<(str)
        self
      end

      def add_bind(bind)
        @binds << bind
        self
      end

      def add_binds(binds, proc_for_binds = nil)
        @binds.concat proc_for_binds ? binds.map(&proc_for_binds) : binds
        self
      end

      def value
        @binds
      end
    end
  end
end

bind_param.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class BindParam < Node
      attr_reader :value

      def initialize(value)
        @value = value
        super()
      end

      def hash
        [self.class, self.value].hash
      end

      def eql?(other)
        other.is_a?(BindParam) &&
          value == other.value
      end
      alias :== :eql?

      def nil?
        value.nil?
      end

      def value_before_type_cast
        if value.respond_to?(:value_before_type_cast)
          value.value_before_type_cast
        else
          value
        end
      end

      def infinite?
        value.respond_to?(:infinite?) && value.infinite?
      end

      def unboundable?
        value.respond_to?(:unboundable?) && value.unboundable?
      end
    end
  end
end

bit.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Bit < Type::Value # :nodoc:
          def type
            :bit
          end

          def cast_value(value)
            if ::String === value
              case value
              when /^0x/i
                value[2..-1].hex.to_s(2) # Hexadecimal notation
              else
                value                    # Bit-string notation
              end
            else
              value.to_s
            end
          end

          def serialize(value)
            Data.new(super) if value
          end

          class Data
            def initialize(value)
              @value = value
            end

            def to_s
              value
            end

            def binary?
              /\A[01]*\Z/.match?(value)
            end

            def hex?
              /\A[0-9A-F]*\Z/i.match?(value)
            end

            private
              attr_reader :value
          end
        end
      end
    end
  end
end

bit_varying.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class BitVarying < OID::Bit # :nodoc:
          def type
            :bit_varying
          end
        end
      end
    end
  end
end

branch.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class Preloader
      class Branch # :nodoc:
        attr_reader :association, :children, :parent
        attr_reader :scope, :associate_by_default
        attr_writer :preloaded_records

        def initialize(association:, children:, parent:, associate_by_default:, scope:)
          @association = association
          @parent = parent
          @scope = scope
          @associate_by_default = associate_by_default

          @children = build_children(children)
          @loaders = nil
        end

        def future_classes
          (immediate_future_classes + children.flat_map(&:future_classes)).uniq
        end

        def immediate_future_classes
          if parent.done?
            loaders.flat_map(&:future_classes).uniq
          else
            likely_reflections.reject(&:polymorphic?).flat_map do |reflection|
              reflection.
                chain.
                map(&:klass)
            end.uniq
          end
        end

        def target_classes
          if done?
            preloaded_records.map(&:klass).uniq
          elsif parent.done?
            loaders.map(&:klass).uniq
          else
            likely_reflections.reject(&:polymorphic?).map(&:klass).uniq
          end
        end

        def likely_reflections
          parent_classes = parent.target_classes
          parent_classes.filter_map do |parent_klass|
            parent_klass._reflect_on_association(@association)
          end
        end

        def root?
          parent.nil?
        end

        def source_records
          @parent.preloaded_records
        end

        def preloaded_records
          @preloaded_records ||= loaders.flat_map(&:preloaded_records)
        end

        def done?
          root? || (@loaders && @loaders.all?(&:run?))
        end

        def runnable_loaders
          loaders.flat_map(&:runnable_loaders).reject(&:run?)
        end

        def grouped_records
          h = {}
          polymorphic_parent = !root? && parent.polymorphic?
          source_records.each do |record|
            reflection = record.class._reflect_on_association(association)
            next if polymorphic_parent && !reflection || !record.association(association).klass
            (h[reflection] ||= []) << record
          end
          h
        end

        def preloaders_for_reflection(reflection, reflection_records)
          reflection_records.group_by do |record|
            klass = record.association(association).klass

            if reflection.scope && reflection.scope.arity != 0
              # For instance dependent scopes, the scope is potentially
              # different for each record. To allow this we'll group each
              # object separately into its own preloader
              reflection_scope = reflection.join_scopes(klass.arel_table, klass.predicate_builder, klass, record).inject(&:merge!)
            end

            [klass, reflection_scope]
          end.map do |(rhs_klass, reflection_scope), rs|
            preloader_for(reflection).new(rhs_klass, rs, reflection, scope, reflection_scope, associate_by_default)
          end
        end

        def polymorphic?
          return false if root?
          return @polymorphic if defined?(@polymorphic)

          @polymorphic = source_records.any? do |record|
            reflection = record.class._reflect_on_association(association)
            reflection && reflection.options[:polymorphic]
          end
        end

        def loaders
          @loaders ||=
            grouped_records.flat_map do |reflection, reflection_records|
              preloaders_for_reflection(reflection, reflection_records)
            end
        end

        private
          def build_children(children)
            Array.wrap(children).flat_map { |association|
              Array(association).flat_map { |parent, child|
                Branch.new(
                  parent: self,
                  association: parent,
                  children: child,
                  associate_by_default: associate_by_default,
                  scope: scope
                )
              }
            }
          end

          # Returns a class containing the logic needed to load preload the data
          # and attach it to a relation. The class returned implements a `run` method
          # that accepts a preloader.
          def preloader_for(reflection)
            if reflection.options[:through]
              ThroughAssociation
            else
              Association
            end
          end
      end
    end
  end
end

bytea.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Bytea < Type::Binary # :nodoc:
          def deserialize(value)
            return if value.nil?
            return value.to_s if value.is_a?(Type::Binary::Data)
            PG::Connection.unescape_bytea(super)
          end
        end
      end
    end
  end
end

calculations.rb

# frozen_string_literal: true

require "active_support/core_ext/enumerable"

module ActiveRecord
  module Calculations
    # Count the records.
    #
    #   Person.count
    #   # => the total count of all people
    #
    #   Person.count(:age)
    #   # => returns the total count of all people whose age is present in database
    #
    #   Person.count(:all)
    #   # => performs a COUNT(*) (:all is an alias for '*')
    #
    #   Person.distinct.count(:age)
    #   # => counts the number of different age values
    #
    # If #count is used with {Relation#group}[rdoc-ref:QueryMethods#group],
    # it returns a Hash whose keys represent the aggregated column,
    # and the values are the respective amounts:
    #
    #   Person.group(:city).count
    #   # => { 'Rome' => 5, 'Paris' => 3 }
    #
    # If #count is used with {Relation#group}[rdoc-ref:QueryMethods#group] for multiple columns, it returns a Hash whose
    # keys are an array containing the individual values of each column and the value
    # of each key would be the #count.
    #
    #   Article.group(:status, :category).count
    #   # =>  {["draft", "business"]=>10, ["draft", "technology"]=>4,
    #   #      ["published", "business"]=>0, ["published", "technology"]=>2}
    #
    # If #count is used with {Relation#select}[rdoc-ref:QueryMethods#select], it will count the selected columns:
    #
    #   Person.select(:age).count
    #   # => counts the number of different age values
    #
    # Note: not all valid {Relation#select}[rdoc-ref:QueryMethods#select] expressions are valid #count expressions. The specifics differ
    # between databases. In invalid cases, an error from the database is thrown.
    def count(column_name = nil)
      if block_given?
        unless column_name.nil?
          raise ArgumentError, "Column name argument is not supported when a block is passed."
        end

        super()
      else
        calculate(:count, column_name)
      end
    end

    # Calculates the average value on a given column. Returns +nil+ if there's
    # no row. See #calculate for examples with options.
    #
    #   Person.average(:age) # => 35.8
    def average(column_name)
      calculate(:average, column_name)
    end

    # Calculates the minimum value on a given column. The value is returned
    # with the same data type of the column, or +nil+ if there's no row. See
    # #calculate for examples with options.
    #
    #   Person.minimum(:age) # => 7
    def minimum(column_name)
      calculate(:minimum, column_name)
    end

    # Calculates the maximum value on a given column. The value is returned
    # with the same data type of the column, or +nil+ if there's no row. See
    # #calculate for examples with options.
    #
    #   Person.maximum(:age) # => 93
    def maximum(column_name)
      calculate(:maximum, column_name)
    end

    # Calculates the sum of values on a given column. The value is returned
    # with the same data type of the column, +0+ if there's no row. See
    # #calculate for examples with options.
    #
    #   Person.sum(:age) # => 4562
    def sum(identity_or_column = nil, &block)
      if block_given?
        values = map(&block)
        if identity_or_column.nil? && (values.first.is_a?(Numeric) || values.first(1) == [])
          identity_or_column = 0
        end

        if identity_or_column.nil?
          ActiveSupport::Deprecation.warn(<<-MSG.squish)
            Rails 7.0 has deprecated Enumerable.sum in favor of Ruby's native implementation available since 2.4.
            Sum of non-numeric elements requires an initial argument.
          MSG
          values.inject(:+) || 0
        else
          values.sum(identity_or_column)
        end
      else
        calculate(:sum, identity_or_column)
      end
    end

    # This calculates aggregate values in the given column. Methods for #count, #sum, #average,
    # #minimum, and #maximum have been added as shortcuts.
    #
    #   Person.calculate(:count, :all) # The same as Person.count
    #   Person.average(:age) # SELECT AVG(age) FROM people...
    #
    #   # Selects the minimum age for any family without any minors
    #   Person.group(:last_name).having("min(age) > 17").minimum(:age)
    #
    #   Person.sum("2 * age")
    #
    # There are two basic forms of output:
    #
    # * Single aggregate value: The single value is type cast to Integer for COUNT, Float
    #   for AVG, and the given column's type for everything else.
    #
    # * Grouped values: This returns an ordered hash of the values and groups them. It
    #   takes either a column name, or the name of a belongs_to association.
    #
    #      values = Person.group('last_name').maximum(:age)
    #      puts values["Drake"]
    #      # => 43
    #
    #      drake  = Family.find_by(last_name: 'Drake')
    #      values = Person.group(:family).maximum(:age) # Person belongs_to :family
    #      puts values[drake]
    #      # => 43
    #
    #      values.each do |family, max_age|
    #        ...
    #      end
    def calculate(operation, column_name)
      if has_include?(column_name)
        relation = apply_join_dependency

        if operation.to_s.downcase == "count"
          unless distinct_value || distinct_select?(column_name || select_for_count)
            relation.distinct!
            relation.select_values = [ klass.primary_key || table[Arel.star] ]
          end
          # PostgreSQL: ORDER BY expressions must appear in SELECT list when using DISTINCT
          relation.order_values = [] if group_values.empty?
        end

        relation.calculate(operation, column_name)
      else
        perform_calculation(operation, column_name)
      end
    end

    # Use #pluck as a shortcut to select one or more attributes without
    # loading an entire record object per row.
    #
    #   Person.pluck(:name)
    #
    # instead of
    #
    #   Person.all.map(&:name)
    #
    # Pluck returns an Array of attribute values type-casted to match
    # the plucked column names, if they can be deduced. Plucking an SQL fragment
    # returns String values by default.
    #
    #   Person.pluck(:name)
    #   # SELECT people.name FROM people
    #   # => ['David', 'Jeremy', 'Jose']
    #
    #   Person.pluck(:id, :name)
    #   # SELECT people.id, people.name FROM people
    #   # => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']]
    #
    #   Person.distinct.pluck(:role)
    #   # SELECT DISTINCT role FROM people
    #   # => ['admin', 'member', 'guest']
    #
    #   Person.where(age: 21).limit(5).pluck(:id)
    #   # SELECT people.id FROM people WHERE people.age = 21 LIMIT 5
    #   # => [2, 3]
    #
    #   Person.pluck(Arel.sql('DATEDIFF(updated_at, created_at)'))
    #   # SELECT DATEDIFF(updated_at, created_at) FROM people
    #   # => ['0', '27761', '173']
    #
    # See also #ids.
    #
    def pluck(*column_names)
      if loaded? && all_attributes?(column_names)
        return records.pluck(*column_names)
      end

      if has_include?(column_names.first)
        relation = apply_join_dependency
        relation.pluck(*column_names)
      else
        klass.disallow_raw_sql!(column_names)
        columns = arel_columns(column_names)
        relation = spawn
        relation.select_values = columns
        result = skip_query_cache_if_necessary do
          if where_clause.contradiction?
            ActiveRecord::Result.empty
          else
            klass.connection.select_all(relation.arel, "#{klass.name} Pluck")
          end
        end
        type_cast_pluck_values(result, columns)
      end
    end

    # Pick the value(s) from the named column(s) in the current relation.
    # This is short-hand for <tt>relation.limit(1).pluck(*column_names).first</tt>, and is primarily useful
    # when you have a relation that's already narrowed down to a single row.
    #
    # Just like #pluck, #pick will only load the actual value, not the entire record object, so it's also
    # more efficient. The value is, again like with pluck, typecast by the column type.
    #
    #   Person.where(id: 1).pick(:name)
    #   # SELECT people.name FROM people WHERE id = 1 LIMIT 1
    #   # => 'David'
    #
    #   Person.where(id: 1).pick(:name, :email_address)
    #   # SELECT people.name, people.email_address FROM people WHERE id = 1 LIMIT 1
    #   # => [ 'David', 'david@loudthinking.com' ]
    def pick(*column_names)
      if loaded? && all_attributes?(column_names)
        return records.pick(*column_names)
      end

      limit(1).pluck(*column_names).first
    end

    # Pluck all the ID's for the relation using the table's primary key
    #
    #   Person.ids # SELECT people.id FROM people
    #   Person.joins(:companies).ids # SELECT people.id FROM people INNER JOIN companies ON companies.person_id = people.id
    def ids
      pluck primary_key
    end

    private
      def all_attributes?(column_names)
        (column_names.map(&:to_s) - @klass.attribute_names - @klass.attribute_aliases.keys).empty?
      end

      def has_include?(column_name)
        eager_loading? || (includes_values.present? && column_name && column_name != :all)
      end

      def perform_calculation(operation, column_name)
        operation = operation.to_s.downcase

        # If #count is used with #distinct (i.e. `relation.distinct.count`) it is
        # considered distinct.
        distinct = distinct_value

        if operation == "count"
          column_name ||= select_for_count
          if column_name == :all
            if !distinct
              distinct = distinct_select?(select_for_count) if group_values.empty?
            elsif group_values.any? || select_values.empty? && order_values.empty?
              column_name = primary_key
            end
          elsif distinct_select?(column_name)
            distinct = nil
          end
        end

        if group_values.any?
          execute_grouped_calculation(operation, column_name, distinct)
        else
          execute_simple_calculation(operation, column_name, distinct)
        end
      end

      def distinct_select?(column_name)
        column_name.is_a?(::String) && /\bDISTINCT[\s(]/i.match?(column_name)
      end

      def aggregate_column(column_name)
        return column_name if Arel::Expressions === column_name

        arel_column(column_name.to_s) do |name|
          Arel.sql(column_name == :all ? "*" : name)
        end
      end

      def operation_over_aggregate_column(column, operation, distinct)
        operation == "count" ? column.count(distinct) : column.public_send(operation)
      end

      def execute_simple_calculation(operation, column_name, distinct) # :nodoc:
        if operation == "count" && (column_name == :all && distinct || has_limit_or_offset?)
          # Shortcut when limit is zero.
          return 0 if limit_value == 0

          query_builder = build_count_subquery(spawn, column_name, distinct)
        else
          # PostgreSQL doesn't like ORDER BY when there are no GROUP BY
          relation = unscope(:order).distinct!(false)

          column = aggregate_column(column_name)
          select_value = operation_over_aggregate_column(column, operation, distinct)
          select_value.distinct = true if operation == "sum" && distinct

          relation.select_values = [select_value]

          query_builder = relation.arel
        end

        result = skip_query_cache_if_necessary { @klass.connection.select_all(query_builder, "#{@klass.name} #{operation.capitalize}") }

        if operation != "count"
          type = column.try(:type_caster) ||
            lookup_cast_type_from_join_dependencies(column_name.to_s) || Type.default_value
          type = type.subtype if Enum::EnumType === type
        end

        type_cast_calculated_value(result.cast_values.first, operation, type)
      end

      def execute_grouped_calculation(operation, column_name, distinct) # :nodoc:
        group_fields = group_values
        group_fields = group_fields.uniq if group_fields.size > 1

        if group_fields.size == 1 && group_fields.first.respond_to?(:to_sym)
          association  = klass._reflect_on_association(group_fields.first)
          associated   = association && association.belongs_to? # only count belongs_to associations
          group_fields = Array(association.foreign_key) if associated
        end
        group_fields = arel_columns(group_fields)

        group_aliases = group_fields.map { |field|
          field = connection.visitor.compile(field) if Arel.arel_node?(field)
          column_alias_for(field.to_s.downcase)
        }
        group_columns = group_aliases.zip(group_fields)

        column = aggregate_column(column_name)
        column_alias = column_alias_for("#{operation} #{column_name.to_s.downcase}")
        select_value = operation_over_aggregate_column(column, operation, distinct)
        select_value.as(connection.quote_column_name(column_alias))

        select_values = [select_value]
        select_values += self.select_values unless having_clause.empty?

        select_values.concat group_columns.map { |aliaz, field|
          aliaz = connection.quote_column_name(aliaz)
          if field.respond_to?(:as)
            field.as(aliaz)
          else
            "#{field} AS #{aliaz}"
          end
        }

        relation = except(:group).distinct!(false)
        relation.group_values  = group_fields
        relation.select_values = select_values

        calculated_data = skip_query_cache_if_necessary { @klass.connection.select_all(relation.arel, "#{@klass.name} #{operation.capitalize}") }

        if association
          key_ids     = calculated_data.collect { |row| row[group_aliases.first] }
          key_records = association.klass.base_class.where(association.klass.base_class.primary_key => key_ids)
          key_records = key_records.index_by(&:id)
        end

        key_types = group_columns.each_with_object({}) do |(aliaz, col_name), types|
          types[aliaz] = type_for(col_name) do
            calculated_data.column_types.fetch(aliaz, Type.default_value)
          end
        end

        hash_rows = calculated_data.cast_values(key_types).map! do |row|
          calculated_data.columns.each_with_object({}).with_index do |(col_name, hash), i|
            hash[col_name] = row[i]
          end
        end

        if operation != "count"
          type = column.try(:type_caster) ||
            lookup_cast_type_from_join_dependencies(column_name.to_s) || Type.default_value
          type = type.subtype if Enum::EnumType === type
        end

        hash_rows.each_with_object({}) do |row, result|
          key = group_aliases.map { |aliaz| row[aliaz] }
          key = key.first if key.size == 1
          key = key_records[key] if associated

          result[key] = type_cast_calculated_value(row[column_alias], operation, type)
        end
      end

      # Converts the given field to the value that the database adapter returns as
      # a usable column name:
      #
      #   column_alias_for("users.id")                 # => "users_id"
      #   column_alias_for("sum(id)")                  # => "sum_id"
      #   column_alias_for("count(distinct users.id)") # => "count_distinct_users_id"
      #   column_alias_for("count(*)")                 # => "count_all"
      def column_alias_for(field)
        column_alias = +field
        column_alias.gsub!(/\*/, "all")
        column_alias.gsub!(/\W+/, " ")
        column_alias.strip!
        column_alias.gsub!(/ +/, "_")

        connection.table_alias_for(column_alias)
      end

      def type_for(field, &block)
        field_name = field.respond_to?(:name) ? field.name.to_s : field.to_s.split(".").last
        @klass.type_for_attribute(field_name, &block)
      end

      def lookup_cast_type_from_join_dependencies(name, join_dependencies = build_join_dependencies)
        each_join_dependencies(join_dependencies) do |join|
          type = join.base_klass.attribute_types.fetch(name, nil)
          return type if type
        end
        nil
      end

      def type_cast_pluck_values(result, columns)
        cast_types = if result.columns.size != columns.size
          klass.attribute_types
        else
          join_dependencies = nil
          columns.map.with_index do |column, i|
            column.try(:type_caster) ||
              klass.attribute_types.fetch(name = result.columns[i]) do
                join_dependencies ||= build_join_dependencies
                lookup_cast_type_from_join_dependencies(name, join_dependencies) ||
                  result.column_types[name] || Type.default_value
              end
          end
        end
        result.cast_values(cast_types)
      end

      def type_cast_calculated_value(value, operation, type)
        case operation
        when "count"
          value.to_i
        when "sum"
          type.deserialize(value || 0)
        when "average"
          case type.type
          when :integer, :decimal
            value&.to_d
          else
            type.deserialize(value)
          end
        else # "minimum", "maximum"
          type.deserialize(value)
        end
      end

      def select_for_count
        if select_values.present?
          return select_values.first if select_values.one?
          select_values.join(", ")
        else
          :all
        end
      end

      def build_count_subquery(relation, column_name, distinct)
        if column_name == :all
          column_alias = Arel.star
          relation.select_values = [ Arel.sql(FinderMethods::ONE_AS_ONE) ] unless distinct
        else
          column_alias = Arel.sql("count_column")
          relation.select_values = [ aggregate_column(column_name).as(column_alias) ]
        end

        subquery_alias = Arel.sql("subquery_for_count")
        select_value = operation_over_aggregate_column(column_alias, "count", false)

        relation.build_subquery(subquery_alias, select_value)
      end
  end
end

callbacks.rb

# frozen_string_literal: true

module ActiveRecord
  # = Active Record \Callbacks
  #
  # \Callbacks are hooks into the life cycle of an Active Record object that allow you to trigger logic
  # before or after a change in the object state. This can be used to make sure that associated and
  # dependent objects are deleted when {ActiveRecord::Base#destroy}[rdoc-ref:Persistence#destroy] is called (by overwriting +before_destroy+) or
  # to massage attributes before they're validated (by overwriting +before_validation+).
  # As an example of the callbacks initiated, consider the {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] call for a new record:
  #
  # * (-) <tt>save</tt>
  # * (-) <tt>valid</tt>
  # * (1) <tt>before_validation</tt>
  # * (-) <tt>validate</tt>
  # * (2) <tt>after_validation</tt>
  # * (3) <tt>before_save</tt>
  # * (4) <tt>before_create</tt>
  # * (-) <tt>create</tt>
  # * (5) <tt>after_create</tt>
  # * (6) <tt>after_save</tt>
  # * (7) <tt>after_commit</tt>
  #
  # Also, an <tt>after_rollback</tt> callback can be configured to be triggered whenever a rollback is issued.
  # Check out ActiveRecord::Transactions for more details about <tt>after_commit</tt> and
  # <tt>after_rollback</tt>.
  #
  # Additionally, an <tt>after_touch</tt> callback is triggered whenever an
  # object is touched.
  #
  # Lastly an <tt>after_find</tt> and <tt>after_initialize</tt> callback is triggered for each object that
  # is found and instantiated by a finder, with <tt>after_initialize</tt> being triggered after new objects
  # are instantiated as well.
  #
  # There are nineteen callbacks in total, which give a lot of control over how to react and prepare for each state in the
  # Active Record life cycle. The sequence for calling {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] for an existing record is similar,
  # except that each <tt>_create</tt> callback is replaced by the corresponding <tt>_update</tt> callback.
  #
  # Examples:
  #   class CreditCard < ActiveRecord::Base
  #     # Strip everything but digits, so the user can specify "555 234 34" or
  #     # "5552-3434" and both will mean "55523434"
  #     before_validation(on: :create) do
  #       self.number = number.gsub(/[^0-9]/, "") if attribute_present?("number")
  #     end
  #   end
  #
  #   class Subscription < ActiveRecord::Base
  #     before_create :record_signup
  #
  #     private
  #       def record_signup
  #         self.signed_up_on = Date.today
  #       end
  #   end
  #
  #   class Firm < ActiveRecord::Base
  #     # Disables access to the system, for associated clients and people when the firm is destroyed
  #     before_destroy { |record| Person.where(firm_id: record.id).update_all(access: 'disabled')   }
  #     before_destroy { |record| Client.where(client_of: record.id).update_all(access: 'disabled') }
  #   end
  #
  # == Inheritable callback queues
  #
  # Besides the overwritable callback methods, it's also possible to register callbacks through the
  # use of the callback macros. Their main advantage is that the macros add behavior into a callback
  # queue that is kept intact through an inheritance hierarchy.
  #
  #   class Topic < ActiveRecord::Base
  #     before_destroy :destroy_author
  #   end
  #
  #   class Reply < Topic
  #     before_destroy :destroy_readers
  #   end
  #
  # When <tt>Topic#destroy</tt> is run only +destroy_author+ is called. When <tt>Reply#destroy</tt> is
  # run, both +destroy_author+ and +destroy_readers+ are called.
  #
  # *IMPORTANT:* In order for inheritance to work for the callback queues, you must specify the
  # callbacks before specifying the associations. Otherwise, you might trigger the loading of a
  # child before the parent has registered the callbacks and they won't be inherited.
  #
  # == Types of callbacks
  #
  # There are three types of callbacks accepted by the callback macros: method references (symbol), callback objects,
  # inline methods (using a proc). Method references and callback objects are the recommended approaches,
  # inline methods using a proc are sometimes appropriate (such as for creating mix-ins).
  #
  # The method reference callbacks work by specifying a protected or private method available in the object, like this:
  #
  #   class Topic < ActiveRecord::Base
  #     before_destroy :delete_parents
  #
  #     private
  #       def delete_parents
  #         self.class.delete_by(parent_id: id)
  #       end
  #   end
  #
  # The callback objects have methods named after the callback called with the record as the only parameter, such as:
  #
  #   class BankAccount < ActiveRecord::Base
  #     before_save      EncryptionWrapper.new
  #     after_save       EncryptionWrapper.new
  #     after_initialize EncryptionWrapper.new
  #   end
  #
  #   class EncryptionWrapper
  #     def before_save(record)
  #       record.credit_card_number = encrypt(record.credit_card_number)
  #     end
  #
  #     def after_save(record)
  #       record.credit_card_number = decrypt(record.credit_card_number)
  #     end
  #
  #     alias_method :after_initialize, :after_save
  #
  #     private
  #       def encrypt(value)
  #         # Secrecy is committed
  #       end
  #
  #       def decrypt(value)
  #         # Secrecy is unveiled
  #       end
  #   end
  #
  # So you specify the object you want to be messaged on a given callback. When that callback is triggered, the object has
  # a method by the name of the callback messaged. You can make these callbacks more flexible by passing in other
  # initialization data such as the name of the attribute to work with:
  #
  #   class BankAccount < ActiveRecord::Base
  #     before_save      EncryptionWrapper.new("credit_card_number")
  #     after_save       EncryptionWrapper.new("credit_card_number")
  #     after_initialize EncryptionWrapper.new("credit_card_number")
  #   end
  #
  #   class EncryptionWrapper
  #     def initialize(attribute)
  #       @attribute = attribute
  #     end
  #
  #     def before_save(record)
  #       record.send("#{@attribute}=", encrypt(record.send("#{@attribute}")))
  #     end
  #
  #     def after_save(record)
  #       record.send("#{@attribute}=", decrypt(record.send("#{@attribute}")))
  #     end
  #
  #     alias_method :after_initialize, :after_save
  #
  #     private
  #       def encrypt(value)
  #         # Secrecy is committed
  #       end
  #
  #       def decrypt(value)
  #         # Secrecy is unveiled
  #       end
  #   end
  #
  # == <tt>before_validation*</tt> returning statements
  #
  # If the +before_validation+ callback throws +:abort+, the process will be
  # aborted and {ActiveRecord::Base#save}[rdoc-ref:Persistence#save] will return +false+.
  # If {ActiveRecord::Base#save!}[rdoc-ref:Persistence#save!] is called it will raise an ActiveRecord::RecordInvalid exception.
  # Nothing will be appended to the errors object.
  #
  # == Canceling callbacks
  #
  # If a <tt>before_*</tt> callback throws +:abort+, all the later callbacks and
  # the associated action are cancelled.
  # Callbacks are generally run in the order they are defined, with the exception of callbacks defined as
  # methods on the model, which are called last.
  #
  # == Ordering callbacks
  #
  # Sometimes application code requires that callbacks execute in a specific order. For example, a +before_destroy+
  # callback (+log_children+ in this case) should be executed before records in the +children+ association are destroyed by the
  # <tt>dependent: :destroy</tt> option.
  #
  # Let's look at the code below:
  #
  #   class Topic < ActiveRecord::Base
  #     has_many :children, dependent: :destroy
  #
  #     before_destroy :log_children
  #
  #     private
  #       def log_children
  #         # Child processing
  #       end
  #   end
  #
  # In this case, the problem is that when the +before_destroy+ callback is executed, records in the +children+ association no
  # longer exist because the {ActiveRecord::Base#destroy}[rdoc-ref:Persistence#destroy] callback was executed first.
  # You can use the +prepend+ option on the +before_destroy+ callback to avoid this.
  #
  #   class Topic < ActiveRecord::Base
  #     has_many :children, dependent: :destroy
  #
  #     before_destroy :log_children, prepend: true
  #
  #     private
  #       def log_children
  #         # Child processing
  #       end
  #   end
  #
  # This way, the +before_destroy+ is executed before the <tt>dependent: :destroy</tt> is called, and the data is still available.
  #
  # Also, there are cases when you want several callbacks of the same type to
  # be executed in order.
  #
  # For example:
  #
  #   class Topic < ActiveRecord::Base
  #     has_many :children
  #
  #     after_save :log_children
  #     after_save :do_something_else
  #
  #     private
  #
  #     def log_children
  #       # Child processing
  #     end
  #
  #     def do_something_else
  #       # Something else
  #     end
  #   end
  #
  # In this case the +log_children+ is executed before +do_something_else+.
  # The same applies to all non-transactional callbacks.
  #
  # As seen below, in case there are multiple transactional callbacks the order
  # is reversed.
  #
  # For example:
  #
  #   class Topic < ActiveRecord::Base
  #     has_many :children
  #
  #     after_commit :log_children
  #     after_commit :do_something_else
  #
  #     private
  #
  #     def log_children
  #       # Child processing
  #     end
  #
  #     def do_something_else
  #       # Something else
  #     end
  #   end
  #
  # In this case the +do_something_else+ is executed before +log_children+.
  #
  # == \Transactions
  #
  # The entire callback chain of a {#save}[rdoc-ref:Persistence#save], {#save!}[rdoc-ref:Persistence#save!],
  # or {#destroy}[rdoc-ref:Persistence#destroy] call runs within a transaction. That includes <tt>after_*</tt> hooks.
  # If everything goes fine a +COMMIT+ is executed once the chain has been completed.
  #
  # If a <tt>before_*</tt> callback cancels the action a +ROLLBACK+ is issued. You
  # can also trigger a +ROLLBACK+ raising an exception in any of the callbacks,
  # including <tt>after_*</tt> hooks. Note, however, that in that case the client
  # needs to be aware of it because an ordinary {#save}[rdoc-ref:Persistence#save] will raise such exception
  # instead of quietly returning +false+.
  #
  # == Debugging callbacks
  #
  # The callback chain is accessible via the <tt>_*_callbacks</tt> method on an object. Active Model \Callbacks support
  # <tt>:before</tt>, <tt>:after</tt> and <tt>:around</tt> as values for the <tt>kind</tt> property. The <tt>kind</tt> property
  # defines what part of the chain the callback runs in.
  #
  # To find all callbacks in the +before_save+ callback chain:
  #
  #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }
  #
  # Returns an array of callback objects that form the +before_save+ chain.
  #
  # To further check if the before_save chain contains a proc defined as <tt>rest_when_dead</tt> use the <tt>filter</tt> property of the callback object:
  #
  #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }.collect(&:filter).include?(:rest_when_dead)
  #
  # Returns true or false depending on whether the proc is contained in the +before_save+ callback chain on a Topic model.
  #
  module Callbacks
    extend ActiveSupport::Concern

    CALLBACKS = [
      :after_initialize, :after_find, :after_touch, :before_validation, :after_validation,
      :before_save, :around_save, :after_save, :before_create, :around_create,
      :after_create, :before_update, :around_update, :after_update,
      :before_destroy, :around_destroy, :after_destroy, :after_commit, :after_rollback
    ]

    module ClassMethods
      include ActiveModel::Callbacks

      ##
      # :method: after_initialize
      #
      # :call-seq: after_initialize(*args, &block)
      #
      # Registers a callback to be called after a record is instantiated. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: after_find
      #
      # :call-seq: after_find(*args, &block)
      #
      # Registers a callback to be called after a record is instantiated
      # via a finder. See ActiveRecord::Callbacks for more information.

      ##
      # :method: after_touch
      #
      # :call-seq: after_touch(*args, &block)
      #
      # Registers a callback to be called after a record is touched. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: before_save
      #
      # :call-seq: before_save(*args, &block)
      #
      # Registers a callback to be called before a record is saved. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: around_save
      #
      # :call-seq: around_save(*args, &block)
      #
      # Registers a callback to be called around the save of a record. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: after_save
      #
      # :call-seq: after_save(*args, &block)
      #
      # Registers a callback to be called after a record is saved. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: before_create
      #
      # :call-seq: before_create(*args, &block)
      #
      # Registers a callback to be called before a record is created. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: around_create
      #
      # :call-seq: around_create(*args, &block)
      #
      # Registers a callback to be called around the creation of a record. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: after_create
      #
      # :call-seq: after_create(*args, &block)
      #
      # Registers a callback to be called after a record is created. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: before_update
      #
      # :call-seq: before_update(*args, &block)
      #
      # Registers a callback to be called before a record is updated. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: around_update
      #
      # :call-seq: around_update(*args, &block)
      #
      # Registers a callback to be called around the update of a record. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: after_update
      #
      # :call-seq: after_update(*args, &block)
      #
      # Registers a callback to be called after a record is updated. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: before_destroy
      #
      # :call-seq: before_destroy(*args, &block)
      #
      # Registers a callback to be called before a record is destroyed. See
      # ActiveRecord::Callbacks for more information.

      ##
      # :method: around_destroy
      #
      # :call-seq: around_destroy(*args, &block)
      #
      # Registers a callback to be called around the destruction of a record.
      # See ActiveRecord::Callbacks for more information.

      ##
      # :method: after_destroy
      #
      # :call-seq: after_destroy(*args, &block)
      #
      # Registers a callback to be called after a record is destroyed. See
      # ActiveRecord::Callbacks for more information.
    end

    included do
      include ActiveModel::Validations::Callbacks

      define_model_callbacks :initialize, :find, :touch, only: :after
      define_model_callbacks :save, :create, :update, :destroy
    end

    def destroy # :nodoc:
      @_destroy_callback_already_called ||= false
      return if @_destroy_callback_already_called
      @_destroy_callback_already_called = true
      _run_destroy_callbacks { super }
    rescue RecordNotDestroyed => e
      @_association_destroy_exception = e
      false
    ensure
      @_destroy_callback_already_called = false
    end

    def touch(*, **) # :nodoc:
      _run_touch_callbacks { super }
    end

    def increment!(attribute, by = 1, touch: nil) # :nodoc:
      touch ? _run_touch_callbacks { super } : super
    end

  private
    def create_or_update(**)
      _run_save_callbacks { super }
    end

    def _create_record
      _run_create_callbacks { super }
    end

    def _update_record
      _run_update_callbacks { super }
    end
  end
end

case.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Case < Arel::Nodes::NodeExpression
      attr_accessor :case, :conditions, :default

      def initialize(expression = nil, default = nil)
        @case = expression
        @conditions = []
        @default = default
      end

      def when(condition, expression = nil)
        @conditions << When.new(Nodes.build_quoted(condition), expression)
        self
      end

      def then(expression)
        @conditions.last.right = Nodes.build_quoted(expression)
        self
      end

      def else(expression)
        @default = Else.new Nodes.build_quoted(expression)
        self
      end

      def initialize_copy(other)
        super
        @case = @case.clone if @case
        @conditions = @conditions.map { |x| x.clone }
        @default = @default.clone if @default
      end

      def hash
        [@case, @conditions, @default].hash
      end

      def eql?(other)
        self.class == other.class &&
          self.case == other.case &&
          self.conditions == other.conditions &&
          self.default == other.default
      end
      alias :== :eql?
    end

    class When < Binary # :nodoc:
    end

    class Else < Unary # :nodoc:
    end
  end
end

casted.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Casted < Arel::Nodes::NodeExpression # :nodoc:
      attr_reader :value, :attribute
      alias :value_before_type_cast :value

      def initialize(value, attribute)
        @value     = value
        @attribute = attribute
        super()
      end

      def nil?; value.nil?; end

      def value_for_database
        if attribute.able_to_type_cast?
          attribute.type_cast_for_database(value)
        else
          value
        end
      end

      def hash
        [self.class, value, attribute].hash
      end

      def eql?(other)
        self.class == other.class &&
          self.value == other.value &&
          self.attribute == other.attribute
      end
      alias :== :eql?
    end

    class Quoted < Arel::Nodes::Unary # :nodoc:
      alias :value_for_database :value
      alias :value_before_type_cast :value

      def nil?; value.nil?; end

      def infinite?
        value.respond_to?(:infinite?) && value.infinite?
      end
    end

    def self.build_quoted(other, attribute = nil)
      case other
      when Arel::Nodes::Node, Arel::Attributes::Attribute, Arel::Table, Arel::SelectManager, Arel::Nodes::SqlLiteral, ActiveModel::Attribute
        other
      else
        case attribute
        when Arel::Attributes::Attribute
          Casted.new other, attribute
        else
          Quoted.new other
        end
      end
    end
  end
end

cidr.rb

# frozen_string_literal: true

require "ipaddr"

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Cidr < Type::Value # :nodoc:
          def type
            :cidr
          end

          def type_cast_for_schema(value)
            # If the subnet mask is equal to /32, don't output it
            if value.prefix == 32
              "\"#{value}\""
            else
              "\"#{value}/#{value.prefix}\""
            end
          end

          def serialize(value)
            if IPAddr === value
              "#{value}/#{value.prefix}"
            else
              value
            end
          end

          def cast_value(value)
            if value.nil?
              nil
            elsif String === value
              begin
                IPAddr.new(value)
              rescue ArgumentError
                nil
              end
            else
              value
            end
          end
        end
      end
    end
  end
end

cipher.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # The algorithm used for encrypting and decrypting +Message+ objects.
    #
    # It uses AES-256-GCM. It will generate a random IV for non deterministic encryption (default)
    # or derive an initialization vector from the encrypted content for deterministic encryption.
    #
    # See +Cipher::Aes256Gcm+.
    class Cipher
      DEFAULT_ENCODING = Encoding::UTF_8

      # Encrypts the provided text and return an encrypted +Message+.
      def encrypt(clean_text, key:, deterministic: false)
        cipher_for(key, deterministic: deterministic).encrypt(clean_text).tap do |message|
          message.headers.encoding = clean_text.encoding.name unless clean_text.encoding == DEFAULT_ENCODING
        end
      end

      # Decrypt the provided +Message+.
      #
      # When +key+ is an Array, it will try all the keys raising a
      # +ActiveRecord::Encryption::Errors::Decryption+ if none works.
      def decrypt(encrypted_message, key:)
        try_to_decrypt_with_each(encrypted_message, keys: Array(key)).tap do |decrypted_text|
          decrypted_text.force_encoding(encrypted_message.headers.encoding || DEFAULT_ENCODING)
        end
      end

      def key_length
        Aes256Gcm.key_length
      end

      def iv_length
        Aes256Gcm.iv_length
      end

      private
        def try_to_decrypt_with_each(encrypted_text, keys:)
          keys.each.with_index do |key, index|
            return cipher_for(key).decrypt(encrypted_text)
          rescue ActiveRecord::Encryption::Errors::Decryption
            raise if index == keys.length - 1
          end
        end

        def cipher_for(secret, deterministic: false)
          Aes256Gcm.new(secret, deterministic: deterministic)
        end
    end
  end
end

collection_association.rb

# frozen_string_literal: true

require "active_support/core_ext/enumerable"

module ActiveRecord
  module Associations
    # = Active Record Association Collection
    #
    # CollectionAssociation is an abstract class that provides common stuff to
    # ease the implementation of association proxies that represent
    # collections. See the class hierarchy in Association.
    #
    #   CollectionAssociation:
    #     HasManyAssociation => has_many
    #       HasManyThroughAssociation + ThroughAssociation => has_many :through
    #
    # The CollectionAssociation class provides common methods to the collections
    # defined by +has_and_belongs_to_many+, +has_many+ or +has_many+ with
    # the +:through association+ option.
    #
    # You need to be careful with assumptions regarding the target: The proxy
    # does not fetch records from the database until it needs them, but new
    # ones created with +build+ are added to the target. So, the target may be
    # non-empty and still lack children waiting to be read from the database.
    # If you look directly to the database you cannot assume that's the entire
    # collection because new records may have been added to the target, etc.
    #
    # If you need to work on all current children, new and existing records,
    # +load_target+ and the +loaded+ flag are your friends.
    class CollectionAssociation < Association # :nodoc:
      # Implements the reader method, e.g. foo.items for Foo.has_many :items
      def reader
        ensure_klass_exists!

        if stale_target?
          reload
        end

        @proxy ||= CollectionProxy.create(klass, self)
        @proxy.reset_scope
      end

      # Implements the writer method, e.g. foo.items= for Foo.has_many :items
      def writer(records)
        replace(records)
      end

      # Implements the ids reader method, e.g. foo.item_ids for Foo.has_many :items
      def ids_reader
        if loaded?
          target.pluck(reflection.association_primary_key)
        elsif !target.empty?
          load_target.pluck(reflection.association_primary_key)
        else
          @association_ids ||= scope.pluck(reflection.association_primary_key)
        end
      end

      # Implements the ids writer method, e.g. foo.item_ids= for Foo.has_many :items
      def ids_writer(ids)
        primary_key = reflection.association_primary_key
        pk_type = klass.type_for_attribute(primary_key)
        ids = Array(ids).compact_blank
        ids.map! { |i| pk_type.cast(i) }

        records = klass.where(primary_key => ids).index_by do |r|
          r.public_send(primary_key)
        end.values_at(*ids).compact

        if records.size != ids.size
          found_ids = records.map { |record| record.public_send(primary_key) }
          not_found_ids = ids - found_ids
          klass.all.raise_record_not_found_exception!(ids, records.size, ids.size, primary_key, not_found_ids)
        else
          replace(records)
        end
      end

      def reset
        super
        @target = []
        @replaced_or_added_targets = Set.new
        @association_ids = nil
      end

      def find(*args)
        if options[:inverse_of] && loaded?
          args_flatten = args.flatten
          model = scope.klass

          if args_flatten.blank?
            error_message = "Couldn't find #{model.name} without an ID"
            raise RecordNotFound.new(error_message, model.name, model.primary_key, args)
          end

          result = find_by_scan(*args)

          result_size = Array(result).size
          if !result || result_size != args_flatten.size
            scope.raise_record_not_found_exception!(args_flatten, result_size, args_flatten.size)
          else
            result
          end
        else
          scope.find(*args)
        end
      end

      def build(attributes = nil, &block)
        if attributes.is_a?(Array)
          attributes.collect { |attr| build(attr, &block) }
        else
          add_to_target(build_record(attributes, &block), replace: true)
        end
      end

      # Add +records+ to this association. Since +<<+ flattens its argument list
      # and inserts each record, +push+ and +concat+ behave identically.
      def concat(*records)
        records = records.flatten
        if owner.new_record?
          load_target
          concat_records(records)
        else
          transaction { concat_records(records) }
        end
      end

      # Removes all records from the association without calling callbacks
      # on the associated records. It honors the +:dependent+ option. However
      # if the +:dependent+ value is +:destroy+ then in that case the +:delete_all+
      # deletion strategy for the association is applied.
      #
      # You can force a particular deletion strategy by passing a parameter.
      #
      # Example:
      #
      # @author.books.delete_all(:nullify)
      # @author.books.delete_all(:delete_all)
      #
      # See delete for more info.
      def delete_all(dependent = nil)
        if dependent && ![:nullify, :delete_all].include?(dependent)
          raise ArgumentError, "Valid values are :nullify or :delete_all"
        end

        dependent = if dependent
          dependent
        elsif options[:dependent] == :destroy
          :delete_all
        else
          options[:dependent]
        end

        delete_or_nullify_all_records(dependent).tap do
          reset
          loaded!
        end
      end

      # Destroy all the records from this association.
      #
      # See destroy for more info.
      def destroy_all
        destroy(load_target).tap do
          reset
          loaded!
        end
      end

      # Removes +records+ from this association calling +before_remove+ and
      # +after_remove+ callbacks.
      #
      # This method is abstract in the sense that +delete_records+ has to be
      # provided by descendants. Note this method does not imply the records
      # are actually removed from the database, that depends precisely on
      # +delete_records+. They are in any case removed from the collection.
      def delete(*records)
        delete_or_destroy(records, options[:dependent])
      end

      # Deletes the +records+ and removes them from this association calling
      # +before_remove+, +after_remove+, +before_destroy+ and +after_destroy+ callbacks.
      #
      # Note that this method removes records from the database ignoring the
      # +:dependent+ option.
      def destroy(*records)
        delete_or_destroy(records, :destroy)
      end

      # Returns the size of the collection by executing a SELECT COUNT(*)
      # query if the collection hasn't been loaded, and calling
      # <tt>collection.size</tt> if it has.
      #
      # If the collection has been already loaded +size+ and +length+ are
      # equivalent. If not and you are going to need the records anyway
      # +length+ will take one less query. Otherwise +size+ is more efficient.
      #
      # This method is abstract in the sense that it relies on
      # +count_records+, which is a method descendants have to provide.
      def size
        if !find_target? || loaded?
          target.size
        elsif @association_ids
          @association_ids.size
        elsif !association_scope.group_values.empty?
          load_target.size
        elsif !association_scope.distinct_value && !target.empty?
          unsaved_records = target.select(&:new_record?)
          unsaved_records.size + count_records
        else
          count_records
        end
      end

      # Returns true if the collection is empty.
      #
      # If the collection has been loaded
      # it is equivalent to <tt>collection.size.zero?</tt>. If the
      # collection has not been loaded, it is equivalent to
      # <tt>!collection.exists?</tt>. If the collection has not already been
      # loaded and you are going to fetch the records anyway it is better to
      # check <tt>collection.length.zero?</tt>.
      def empty?
        if loaded? || @association_ids || reflection.has_cached_counter?
          size.zero?
        else
          target.empty? && !scope.exists?
        end
      end

      # Replace this collection with +other_array+. This will perform a diff
      # and delete/add only records that have changed.
      def replace(other_array)
        other_array.each { |val| raise_on_type_mismatch!(val) }
        original_target = load_target.dup

        if owner.new_record?
          replace_records(other_array, original_target)
        else
          replace_common_records_in_memory(other_array, original_target)
          if other_array != original_target
            transaction { replace_records(other_array, original_target) }
          else
            other_array
          end
        end
      end

      def include?(record)
        if record.is_a?(reflection.klass)
          if record.new_record?
            include_in_memory?(record)
          else
            loaded? ? target.include?(record) : scope.exists?(record.id)
          end
        else
          false
        end
      end

      def load_target
        if find_target?
          @target = merge_target_lists(find_target, target)
        end

        loaded!
        target
      end

      def add_to_target(record, skip_callbacks: false, replace: false, &block)
        replace_on_target(record, skip_callbacks, replace: replace || association_scope.distinct_value, &block)
      end

      def target=(record)
        return super unless reflection.klass.has_many_inversing

        case record
        when nil
          # It's not possible to remove the record from the inverse association.
        when Array
          super
        else
          replace_on_target(record, true, replace: true, inversing: true)
        end
      end

      def scope
        scope = super
        scope.none! if null_scope?
        scope
      end

      def null_scope?
        owner.new_record? && !foreign_key_present?
      end

      def find_from_target?
        loaded? ||
          owner.strict_loading? ||
          reflection.strict_loading? ||
          owner.new_record? ||
          target.any? { |record| record.new_record? || record.changed? }
      end

      private
        def transaction(&block)
          reflection.klass.transaction(&block)
        end

        # We have some records loaded from the database (persisted) and some that are
        # in-memory (memory). The same record may be represented in the persisted array
        # and in the memory array.
        #
        # So the task of this method is to merge them according to the following rules:
        #
        #   * The final array must not have duplicates
        #   * The order of the persisted array is to be preserved
        #   * Any changes made to attributes on objects in the memory array are to be preserved
        #   * Otherwise, attributes should have the value found in the database
        def merge_target_lists(persisted, memory)
          return persisted if memory.empty?
          return memory    if persisted.empty?

          persisted.map! do |record|
            if mem_record = memory.delete(record)

              ((record.attribute_names & mem_record.attribute_names) - mem_record.changed_attribute_names_to_save).each do |name|
                mem_record[name] = record[name]
              end

              mem_record
            else
              record
            end
          end

          persisted + memory.reject(&:persisted?)
        end

        def _create_record(attributes, raise = false, &block)
          unless owner.persisted?
            raise ActiveRecord::RecordNotSaved.new("You cannot call create unless the parent is saved", owner)
          end

          if attributes.is_a?(Array)
            attributes.collect { |attr| _create_record(attr, raise, &block) }
          else
            record = build_record(attributes, &block)
            transaction do
              result = nil
              add_to_target(record) do
                result = insert_record(record, true, raise) {
                  @_was_loaded = loaded?
                }
              end
              raise ActiveRecord::Rollback unless result
            end
            record
          end
        end

        # Do the relevant stuff to insert the given record into the association collection.
        def insert_record(record, validate = true, raise = false, &block)
          if raise
            record.save!(validate: validate, &block)
          else
            record.save(validate: validate, &block)
          end
        end

        def delete_or_destroy(records, method)
          return if records.empty?
          records = find(records) if records.any? { |record| record.kind_of?(Integer) || record.kind_of?(String) }
          records = records.flatten
          records.each { |record| raise_on_type_mismatch!(record) }
          existing_records = records.reject(&:new_record?)

          if existing_records.empty?
            remove_records(existing_records, records, method)
          else
            transaction { remove_records(existing_records, records, method) }
          end
        end

        def remove_records(existing_records, records, method)
          catch(:abort) do
            records.each { |record| callback(:before_remove, record) }
          end || return

          delete_records(existing_records, method) if existing_records.any?
          @target -= records
          @association_ids = nil

          records.each { |record| callback(:after_remove, record) }
        end

        # Delete the given records from the association,
        # using one of the methods +:destroy+, +:delete_all+
        # or +:nullify+ (or +nil+, in which case a default is used).
        def delete_records(records, method)
          raise NotImplementedError
        end

        def replace_records(new_target, original_target)
          delete(difference(target, new_target))

          unless concat(difference(new_target, target))
            @target = original_target
            raise RecordNotSaved, "Failed to replace #{reflection.name} because one or more of the " \
                                  "new records could not be saved."
          end

          target
        end

        def replace_common_records_in_memory(new_target, original_target)
          common_records = intersection(new_target, original_target)
          common_records.each do |record|
            skip_callbacks = true
            replace_on_target(record, skip_callbacks, replace: true)
          end
        end

        def concat_records(records, raise = false)
          result = true

          records.each do |record|
            raise_on_type_mismatch!(record)
            add_to_target(record) do
              unless owner.new_record?
                result &&= insert_record(record, true, raise) {
                  @_was_loaded = loaded?
                }
              end
            end
          end

          raise ActiveRecord::Rollback unless result

          records
        end

        def replace_on_target(record, skip_callbacks, replace:, inversing: false)
          if replace && (!record.new_record? || @replaced_or_added_targets.include?(record))
            index = @target.index(record)
          end

          catch(:abort) do
            callback(:before_add, record)
          end || return unless skip_callbacks

          set_inverse_instance(record)

          @_was_loaded = true

          yield(record) if block_given?

          if !index && @replaced_or_added_targets.include?(record)
            index = @target.index(record)
          end

          @replaced_or_added_targets << record if inversing || index || record.new_record?

          if index
            target[index] = record
          elsif @_was_loaded || !loaded?
            @association_ids = nil
            target << record
          end

          callback(:after_add, record) unless skip_callbacks

          record
        ensure
          @_was_loaded = nil
        end

        def callback(method, record)
          callbacks_for(method).each do |callback|
            callback.call(method, owner, record)
          end
        end

        def callbacks_for(callback_name)
          full_callback_name = "#{callback_name}_for_#{reflection.name}"
          if owner.class.respond_to?(full_callback_name)
            owner.class.send(full_callback_name)
          else
            []
          end
        end

        def include_in_memory?(record)
          if reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
            assoc = owner.association(reflection.through_reflection.name)
            assoc.reader.any? { |source|
              target_reflection = source.send(reflection.source_reflection.name)
              target_reflection.respond_to?(:include?) ? target_reflection.include?(record) : target_reflection == record
            } || target.include?(record)
          else
            target.include?(record)
          end
        end

        # If the :inverse_of option has been
        # specified, then #find scans the entire collection.
        def find_by_scan(*args)
          expects_array = args.first.kind_of?(Array)
          ids           = args.flatten.compact.map(&:to_s).uniq

          if ids.size == 1
            id = ids.first
            record = load_target.detect { |r| id == r.id.to_s }
            expects_array ? [ record ] : record
          else
            load_target.select { |r| ids.include?(r.id.to_s) }
          end
        end
    end
  end
end

collection_proxy.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    # Collection proxies in Active Record are middlemen between an
    # <tt>association</tt>, and its <tt>target</tt> result set.
    #
    # For example, given
    #
    #   class Blog < ActiveRecord::Base
    #     has_many :posts
    #   end
    #
    #   blog = Blog.first
    #
    # The collection proxy returned by <tt>blog.posts</tt> is built from a
    # <tt>:has_many</tt> <tt>association</tt>, and delegates to a collection
    # of posts as the <tt>target</tt>.
    #
    # This class delegates unknown methods to the <tt>association</tt>'s
    # relation class via a delegate cache.
    #
    # The <tt>target</tt> result set is not loaded until needed. For example,
    #
    #   blog.posts.count
    #
    # is computed directly through SQL and does not trigger by itself the
    # instantiation of the actual post records.
    class CollectionProxy < Relation
      def initialize(klass, association, **) # :nodoc:
        @association = association
        super klass

        extensions = association.extensions
        extend(*extensions) if extensions.any?
      end

      def target
        @association.target
      end

      def load_target
        @association.load_target
      end

      # Returns +true+ if the association has been loaded, otherwise +false+.
      #
      #   person.pets.loaded? # => false
      #   person.pets.records
      #   person.pets.loaded? # => true
      def loaded?
        @association.loaded?
      end
      alias :loaded :loaded?

      ##
      # :method: select
      #
      # :call-seq:
      #   select(*fields, &block)
      #
      # Works in two ways.
      #
      # *First:* Specify a subset of fields to be selected from the result set.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.select(:name)
      #   # => [
      #   #      #<Pet id: nil, name: "Fancy-Fancy">,
      #   #      #<Pet id: nil, name: "Spook">,
      #   #      #<Pet id: nil, name: "Choo-Choo">
      #   #    ]
      #
      #   person.pets.select(:id, :name)
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy">,
      #   #      #<Pet id: 2, name: "Spook">,
      #   #      #<Pet id: 3, name: "Choo-Choo">
      #   #    ]
      #
      # Be careful because this also means you're initializing a model
      # object with only the fields that you've selected. If you attempt
      # to access a field except +id+ that is not in the initialized record you'll
      # receive:
      #
      #   person.pets.select(:name).first.person_id
      #   # => ActiveModel::MissingAttributeError: missing attribute: person_id
      #
      # *Second:* You can pass a block so it can be used just like Array#select.
      # This builds an array of objects from the database for the scope,
      # converting them into an array and iterating through them using
      # Array#select.
      #
      #   person.pets.select { |pet| /oo/.match?(pet.name) }
      #   # => [
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]

      # Finds an object in the collection responding to the +id+. Uses the same
      # rules as ActiveRecord::Base.find. Returns ActiveRecord::RecordNotFound
      # error if the object cannot be found.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.find(1) # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #   person.pets.find(4) # => ActiveRecord::RecordNotFound: Couldn't find Pet with 'id'=4
      #
      #   person.pets.find(2) { |pet| pet.name.downcase! }
      #   # => #<Pet id: 2, name: "fancy-fancy", person_id: 1>
      #
      #   person.pets.find(2, 3)
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def find(*args)
        return super if block_given?
        @association.find(*args)
      end

      ##
      # :method: first
      #
      # :call-seq:
      #   first(limit = nil)
      #
      # Returns the first record, or the first +n+ records, from the collection.
      # If the collection is empty, the first form returns +nil+, and the second
      # form returns an empty array.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.first # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.first(2)
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
      #   #    ]
      #
      #   another_person_without.pets          # => []
      #   another_person_without.pets.first    # => nil
      #   another_person_without.pets.first(3) # => []

      ##
      # :method: second
      #
      # :call-seq:
      #   second()
      #
      # Same as #first except returns only the second record.

      ##
      # :method: third
      #
      # :call-seq:
      #   third()
      #
      # Same as #first except returns only the third record.

      ##
      # :method: fourth
      #
      # :call-seq:
      #   fourth()
      #
      # Same as #first except returns only the fourth record.

      ##
      # :method: fifth
      #
      # :call-seq:
      #   fifth()
      #
      # Same as #first except returns only the fifth record.

      ##
      # :method: forty_two
      #
      # :call-seq:
      #   forty_two()
      #
      # Same as #first except returns only the forty second record.
      # Also known as accessing "the reddit".

      ##
      # :method: third_to_last
      #
      # :call-seq:
      #   third_to_last()
      #
      # Same as #first except returns only the third-to-last record.

      ##
      # :method: second_to_last
      #
      # :call-seq:
      #   second_to_last()
      #
      # Same as #first except returns only the second-to-last record.

      # Returns the last record, or the last +n+ records, from the collection.
      # If the collection is empty, the first form returns +nil+, and the second
      # form returns an empty array.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.last # => #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #
      #   person.pets.last(2)
      #   # => [
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   another_person_without.pets         # => []
      #   another_person_without.pets.last    # => nil
      #   another_person_without.pets.last(3) # => []
      def last(limit = nil)
        load_target if find_from_target?
        super
      end

      # Gives a record (or N records if a parameter is supplied) from the collection
      # using the same rules as <tt>ActiveRecord::Base.take</tt>.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.take # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.take(2)
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
      #   #    ]
      #
      #   another_person_without.pets         # => []
      #   another_person_without.pets.take    # => nil
      #   another_person_without.pets.take(2) # => []
      def take(limit = nil)
        load_target if find_from_target?
        super
      end

      # Returns a new object of the collection type that has been instantiated
      # with +attributes+ and linked to this object, but have not yet been saved.
      # You can pass an array of attributes hashes, this will return an array
      # with the new objects.
      #
      #   class Person
      #     has_many :pets
      #   end
      #
      #   person.pets.build
      #   # => #<Pet id: nil, name: nil, person_id: 1>
      #
      #   person.pets.build(name: 'Fancy-Fancy')
      #   # => #<Pet id: nil, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.build([{name: 'Spook'}, {name: 'Choo-Choo'}, {name: 'Brain'}])
      #   # => [
      #   #      #<Pet id: nil, name: "Spook", person_id: 1>,
      #   #      #<Pet id: nil, name: "Choo-Choo", person_id: 1>,
      #   #      #<Pet id: nil, name: "Brain", person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 5 # size of the collection
      #   person.pets.count # => 0 # count from database
      def build(attributes = {}, &block)
        @association.build(attributes, &block)
      end
      alias_method :new, :build

      # Returns a new object of the collection type that has been instantiated with
      # attributes, linked to this object and that has already been saved (if it
      # passes the validations).
      #
      #   class Person
      #     has_many :pets
      #   end
      #
      #   person.pets.create(name: 'Fancy-Fancy')
      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>
      #
      #   person.pets.create([{name: 'Spook'}, {name: 'Choo-Choo'}])
      #   # => [
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 3
      #   person.pets.count # => 3
      #
      #   person.pets.find(1, 2, 3)
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def create(attributes = {}, &block)
        @association.create(attributes, &block)
      end

      # Like #create, except that if the record is invalid, raises an exception.
      #
      #   class Person
      #     has_many :pets
      #   end
      #
      #   class Pet
      #     validates :name, presence: true
      #   end
      #
      #   person.pets.create!(name: nil)
      #   # => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
      def create!(attributes = {}, &block)
        @association.create!(attributes, &block)
      end

      # Replaces this collection with +other_array+. This will perform a diff
      # and delete/add only records that have changed.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [#<Pet id: 1, name: "Gorby", group: "cats", person_id: 1>]
      #
      #   other_pets = [Pet.new(name: 'Puff', group: 'celebrities')]
      #
      #   person.pets.replace(other_pets)
      #
      #   person.pets
      #   # => [#<Pet id: 2, name: "Puff", group: "celebrities", person_id: 1>]
      #
      # If the supplied array has an incorrect association type, it raises
      # an <tt>ActiveRecord::AssociationTypeMismatch</tt> error:
      #
      #   person.pets.replace(["doo", "ggie", "gaga"])
      #   # => ActiveRecord::AssociationTypeMismatch: Pet expected, got String
      def replace(other_array)
        @association.replace(other_array)
      end

      # Deletes all the records from the collection according to the strategy
      # specified by the +:dependent+ option. If no +:dependent+ option is given,
      # then it will follow the default strategy.
      #
      # For <tt>has_many :through</tt> associations, the default deletion strategy is
      # +:delete_all+.
      #
      # For +has_many+ associations, the default deletion strategy is +:nullify+.
      # This sets the foreign keys to +NULL+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets # dependent: :nullify option by default
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete_all
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size # => 0
      #   person.pets      # => []
      #
      #   Pet.find(1, 2, 3)
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>,
      #   #       #<Pet id: 2, name: "Spook", person_id: nil>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: nil>
      #   #    ]
      #
      # Both +has_many+ and <tt>has_many :through</tt> dependencies default to the
      # +:delete_all+ strategy if the +:dependent+ option is set to +:destroy+.
      # Records are not instantiated and callbacks will not be fired.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :destroy
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete_all
      #
      #   Pet.find(1, 2, 3)
      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
      #
      # If it is set to <tt>:delete_all</tt>, all the objects are deleted
      # *without* calling their +destroy+ method.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :delete_all
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete_all
      #
      #   Pet.find(1, 2, 3)
      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
      def delete_all(dependent = nil)
        @association.delete_all(dependent).tap { reset_scope }
      end

      # Deletes the records of the collection directly from the database
      # ignoring the +:dependent+ option. Records are instantiated and it
      # invokes +before_remove+, +after_remove+, +before_destroy+, and
      # +after_destroy+ callbacks.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy_all
      #
      #   person.pets.size # => 0
      #   person.pets      # => []
      #
      #   Pet.find(1) # => Couldn't find Pet with id=1
      def destroy_all
        @association.destroy_all.tap { reset_scope }
      end

      # Deletes the +records+ supplied from the collection according to the strategy
      # specified by the +:dependent+ option. If no +:dependent+ option is given,
      # then it will follow the default strategy. Returns an array with the
      # deleted records.
      #
      # For <tt>has_many :through</tt> associations, the default deletion strategy is
      # +:delete_all+.
      #
      # For +has_many+ associations, the default deletion strategy is +:nullify+.
      # This sets the foreign keys to +NULL+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets # dependent: :nullify option by default
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete(Pet.find(1))
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   Pet.find(1)
      #   # => #<Pet id: 1, name: "Fancy-Fancy", person_id: nil>
      #
      # If it is set to <tt>:destroy</tt> all the +records+ are removed by calling
      # their +destroy+ method. See +destroy+ for more information.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :destroy
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete(Pet.find(1), Pet.find(3))
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size # => 1
      #   person.pets
      #   # => [#<Pet id: 2, name: "Spook", person_id: 1>]
      #
      #   Pet.find(1, 3)
      #   # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 3)
      #
      # If it is set to <tt>:delete_all</tt>, all the +records+ are deleted
      # *without* calling their +destroy+ method.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets, dependent: :delete_all
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete(Pet.find(1))
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   Pet.find(1)
      #   # => ActiveRecord::RecordNotFound: Couldn't find Pet with 'id'=1
      #
      # You can pass +Integer+ or +String+ values, it finds the records
      # responding to the +id+ and executes delete on them.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.delete("1")
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.delete(2, 3)
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def delete(*records)
        @association.delete(*records).tap { reset_scope }
      end

      # Destroys the +records+ supplied and removes them from the collection.
      # This method will _always_ remove record from the database ignoring
      # the +:dependent+ option. Returns an array with the removed records.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy(Pet.find(1))
      #   # => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy(Pet.find(2), Pet.find(3))
      #   # => [
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 0
      #   person.pets       # => []
      #
      #   Pet.find(1, 2, 3) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (1, 2, 3)
      #
      # You can pass +Integer+ or +String+ values, it finds the records
      # responding to the +id+ and then deletes them from the database.
      #
      #   person.pets.size # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy("4")
      #   # => #<Pet id: 4, name: "Benny", person_id: 1>
      #
      #   person.pets.size # => 2
      #   person.pets
      #   # => [
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   person.pets.destroy(5, 6)
      #   # => [
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   person.pets.size  # => 0
      #   person.pets       # => []
      #
      #   Pet.find(4, 5, 6) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with 'id': (4, 5, 6)
      def destroy(*records)
        @association.destroy(*records).tap { reset_scope }
      end

      ##
      # :method: distinct
      #
      # :call-seq:
      #   distinct(value = true)
      #
      # Specifies whether the records should be unique or not.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.select(:name)
      #   # => [
      #   #      #<Pet name: "Fancy-Fancy">,
      #   #      #<Pet name: "Fancy-Fancy">
      #   #    ]
      #
      #   person.pets.select(:name).distinct
      #   # => [#<Pet name: "Fancy-Fancy">]
      #
      #   person.pets.select(:name).distinct.distinct(false)
      #   # => [
      #   #      #<Pet name: "Fancy-Fancy">,
      #   #      #<Pet name: "Fancy-Fancy">
      #   #    ]

      #--
      def calculate(operation, column_name)
        null_scope? ? scope.calculate(operation, column_name) : super
      end

      def pluck(*column_names)
        null_scope? ? scope.pluck(*column_names) : super
      end

      ##
      # :method: count
      #
      # :call-seq:
      #   count(column_name = nil, &block)
      #
      # Count all records.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   # This will perform the count using SQL.
      #   person.pets.count # => 3
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      # Passing a block will select all of a person's pets in SQL and then
      # perform the count using Ruby.
      #
      #   person.pets.count { |pet| pet.name.include?('-') } # => 2

      # Returns the size of the collection. If the collection hasn't been loaded,
      # it executes a <tt>SELECT COUNT(*)</tt> query. Else it calls <tt>collection.size</tt>.
      #
      # If the collection has been already loaded +size+ and +length+ are
      # equivalent. If not and you are going to need the records anyway
      # +length+ will take one less query. Otherwise +size+ is more efficient.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 3
      #   # executes something like SELECT COUNT(*) FROM "pets" WHERE "pets"."person_id" = 1
      #
      #   person.pets # This will execute a SELECT * FROM query
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      #
      #   person.pets.size # => 3
      #   # Because the collection is already loaded, this will behave like
      #   # collection.size and no SQL count query is executed.
      def size
        @association.size
      end

      ##
      # :method: length
      #
      # :call-seq:
      #   length()
      #
      # Returns the size of the collection calling +size+ on the target.
      # If the collection has been already loaded, +length+ and +size+ are
      # equivalent. If not and you are going to need the records anyway this
      # method will take one less query. Otherwise +size+ is more efficient.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.length # => 3
      #   # executes something like SELECT "pets".* FROM "pets" WHERE "pets"."person_id" = 1
      #
      #   # Because the collection is loaded, you can
      #   # call the collection with no additional queries:
      #   person.pets
      #   # => [
      #   #       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #       #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]

      # Returns +true+ if the collection is empty. If the collection has been
      # loaded it is equivalent
      # to <tt>collection.size.zero?</tt>. If the collection has not been loaded,
      # it is equivalent to <tt>!collection.exists?</tt>. If the collection has
      # not already been loaded and you are going to fetch the records anyway it
      # is better to check <tt>collection.load.empty?</tt>.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.count  # => 1
      #   person.pets.empty? # => false
      #
      #   person.pets.delete_all
      #
      #   person.pets.count  # => 0
      #   person.pets.empty? # => true
      def empty?
        @association.empty?
      end

      ##
      # :method: any?
      #
      # :call-seq:
      #   any?()
      #
      # Returns +true+ if the collection is not empty.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.count # => 0
      #   person.pets.any?  # => false
      #
      #   person.pets << Pet.new(name: 'Snoop')
      #   person.pets.count # => 1
      #   person.pets.any?  # => true
      #
      # Calling it without a block when the collection is not yet
      # loaded is equivalent to <tt>collection.exists?</tt>.
      # If you're going to load the collection anyway, it is better
      # to call <tt>collection.load.any?</tt> to avoid an extra query.
      #
      # You can also pass a +block+ to define criteria. The behavior
      # is the same, it returns true if the collection based on the
      # criteria is not empty.
      #
      #   person.pets
      #   # => [#<Pet name: "Snoop", group: "dogs">]
      #
      #   person.pets.any? do |pet|
      #     pet.group == 'cats'
      #   end
      #   # => false
      #
      #   person.pets.any? do |pet|
      #     pet.group == 'dogs'
      #   end
      #   # => true

      ##
      # :method: many?
      #
      # :call-seq:
      #   many?()
      #
      # Returns true if the collection has more than one record.
      # Equivalent to <tt>collection.size > 1</tt>.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.count # => 1
      #   person.pets.many? # => false
      #
      #   person.pets << Pet.new(name: 'Snoopy')
      #   person.pets.count # => 2
      #   person.pets.many? # => true
      #
      # You can also pass a +block+ to define criteria. The
      # behavior is the same, it returns true if the collection
      # based on the criteria has more than one record.
      #
      #   person.pets
      #   # => [
      #   #      #<Pet name: "Gorby", group: "cats">,
      #   #      #<Pet name: "Puff", group: "cats">,
      #   #      #<Pet name: "Snoop", group: "dogs">
      #   #    ]
      #
      #   person.pets.many? do |pet|
      #     pet.group == 'dogs'
      #   end
      #   # => false
      #
      #   person.pets.many? do |pet|
      #     pet.group == 'cats'
      #   end
      #   # => true

      # Returns +true+ if the given +record+ is present in the collection.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets # => [#<Pet id: 20, name: "Snoop">]
      #
      #   person.pets.include?(Pet.find(20)) # => true
      #   person.pets.include?(Pet.find(21)) # => false
      def include?(record)
        !!@association.include?(record)
      end

      def proxy_association # :nodoc:
        @association
      end

      # Returns a <tt>Relation</tt> object for the records in this association
      def scope
        @scope ||= @association.scope
      end

      # Equivalent to <tt>Array#==</tt>. Returns +true+ if the two arrays
      # contain the same number of elements and if each element is equal
      # to the corresponding element in the +other+ array, otherwise returns
      # +false+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>
      #   #    ]
      #
      #   other = person.pets.to_ary
      #
      #   person.pets == other
      #   # => true
      #
      #   other = [Pet.new(id: 1), Pet.new(id: 2)]
      #
      #   person.pets == other
      #   # => false
      def ==(other)
        load_target == other
      end

      ##
      # :method: to_ary
      #
      # :call-seq:
      #   to_ary()
      #
      # Returns a new array of objects from the collection. If the collection
      # hasn't been loaded, it fetches the records from the database.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   other_pets = person.pets.to_ary
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]
      #
      #   other_pets.replace([Pet.new(name: 'BooGoo')])
      #
      #   other_pets
      #   # => [#<Pet id: nil, name: "BooGoo", person_id: 1>]
      #
      #   person.pets
      #   # This is not affected by replace
      #   # => [
      #   #       #<Pet id: 4, name: "Benny", person_id: 1>,
      #   #       #<Pet id: 5, name: "Brain", person_id: 1>,
      #   #       #<Pet id: 6, name: "Boss",  person_id: 1>
      #   #    ]

      def records # :nodoc:
        load_target
      end

      # Adds one or more +records+ to the collection by setting their foreign keys
      # to the association's primary key. Since <tt><<</tt> flattens its argument list and
      # inserts each record, +push+ and +concat+ behave identically. Returns +self+
      # so several appends may be chained together.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets.size # => 0
      #   person.pets << Pet.new(name: 'Fancy-Fancy')
      #   person.pets << [Pet.new(name: 'Spook'), Pet.new(name: 'Choo-Choo')]
      #   person.pets.size # => 3
      #
      #   person.id # => 1
      #   person.pets
      #   # => [
      #   #      #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
      #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
      #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
      #   #    ]
      def <<(*records)
        proxy_association.concat(records) && self
      end
      alias_method :push, :<<
      alias_method :append, :<<
      alias_method :concat, :<<

      def prepend(*args) # :nodoc:
        raise NoMethodError, "prepend on association is not defined. Please use <<, push or append"
      end

      # Equivalent to +delete_all+. The difference is that returns +self+, instead
      # of an array with the deleted objects, so methods can be chained. See
      # +delete_all+ for more information.
      # Note that because +delete_all+ removes records by directly
      # running an SQL query into the database, the +updated_at+ column of
      # the object is not changed.
      def clear
        delete_all
        self
      end

      # Reloads the collection from the database. Returns +self+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets # uses the pets cache
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets.reload # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      def reload
        proxy_association.reload(true)
        reset_scope
      end

      # Unloads the association. Returns +self+.
      #
      #   class Person < ActiveRecord::Base
      #     has_many :pets
      #   end
      #
      #   person.pets # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets # uses the pets cache
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      #
      #   person.pets.reset # clears the pets cache
      #
      #   person.pets  # fetches pets from the database
      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
      def reset
        proxy_association.reset
        proxy_association.reset_scope
        reset_scope
      end

      def reset_scope # :nodoc:
        @offsets = @take = nil
        @scope = nil
        self
      end

      def inspect # :nodoc:
        load_target if find_from_target?
        super
      end

      delegate_methods = [
        QueryMethods,
        SpawnMethods,
      ].flat_map { |klass|
        klass.public_instance_methods(false)
      } - self.public_instance_methods(false) - [:select] + [
        :scoping, :values, :insert, :insert_all, :insert!, :insert_all!, :upsert, :upsert_all
      ]

      delegate(*delegate_methods, to: :scope)

      private
        def find_nth_with_limit(index, limit)
          load_target if find_from_target?
          super
        end

        def find_nth_from_last(index)
          load_target if find_from_target?
          super
        end

        def null_scope?
          @association.null_scope?
        end

        def find_from_target?
          @association.find_from_target?
        end

        def exec_queries
          load_target
        end
    end
  end
end

column.rb

# frozen_string_literal: true

require "active_support/core_ext/object/blank"

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      class Column < ConnectionAdapters::Column # :nodoc:
        delegate :oid, :fmod, to: :sql_type_metadata

        def initialize(*, serial: nil, generated: nil, **)
          super
          @serial = serial
          @generated = generated
        end

        def serial?
          @serial
        end

        def virtual?
          # We assume every generated column is virtual, no matter the concrete type
          @generated.present?
        end

        def has_default?
          super && !virtual?
        end

        def array
          sql_type_metadata.sql_type.end_with?("[]")
        end
        alias :array? :array

        def enum?
          type == :enum
        end

        def sql_type
          super.delete_suffix("[]")
        end

        def init_with(coder)
          @serial = coder["serial"]
          super
        end

        def encode_with(coder)
          coder["serial"] = @serial
          super
        end

        def ==(other)
          other.is_a?(Column) &&
            super &&
            serial? == other.serial?
        end
        alias :eql? :==

        def hash
          Column.hash ^
            super.hash ^
            serial?.hash
        end
      end
    end
    PostgreSQLColumn = PostgreSQL::Column # :nodoc:
  end
end

command_recorder.rb

# frozen_string_literal: true

module ActiveRecord
  class Migration
    # <tt>ActiveRecord::Migration::CommandRecorder</tt> records commands done during
    # a migration and knows how to reverse those commands. The CommandRecorder
    # knows how to invert the following commands:
    #
    # * add_column
    # * add_foreign_key
    # * add_check_constraint
    # * add_index
    # * add_reference
    # * add_timestamps
    # * change_column
    # * change_column_default (must supply a +:from+ and +:to+ option)
    # * change_column_null
    # * change_column_comment (must supply a +:from+ and +:to+ option)
    # * change_table_comment (must supply a +:from+ and +:to+ option)
    # * create_join_table
    # * create_table
    # * disable_extension
    # * drop_join_table
    # * drop_table (must supply a block)
    # * enable_extension
    # * remove_column (must supply a type)
    # * remove_columns (must specify at least one column name or more)
    # * remove_foreign_key (must supply a second table)
    # * remove_check_constraint
    # * remove_index
    # * remove_reference
    # * remove_timestamps
    # * rename_column
    # * rename_index
    # * rename_table
    class CommandRecorder
      ReversibleAndIrreversibleMethods = [
        :create_table, :create_join_table, :rename_table, :add_column, :remove_column,
        :rename_index, :rename_column, :add_index, :remove_index, :add_timestamps, :remove_timestamps,
        :change_column_default, :add_reference, :remove_reference, :transaction,
        :drop_join_table, :drop_table, :execute_block, :enable_extension, :disable_extension,
        :change_column, :execute, :remove_columns, :change_column_null,
        :add_foreign_key, :remove_foreign_key,
        :change_column_comment, :change_table_comment,
        :add_check_constraint, :remove_check_constraint
      ]
      include JoinTable

      attr_accessor :commands, :delegate, :reverting

      def initialize(delegate = nil)
        @commands = []
        @delegate = delegate
        @reverting = false
      end

      # While executing the given block, the recorded will be in reverting mode.
      # All commands recorded will end up being recorded reverted
      # and in reverse order.
      # For example:
      #
      #   recorder.revert{ recorder.record(:rename_table, [:old, :new]) }
      #   # same effect as recorder.record(:rename_table, [:new, :old])
      def revert
        @reverting = !@reverting
        previous = @commands
        @commands = []
        yield
      ensure
        @commands = previous.concat(@commands.reverse)
        @reverting = !@reverting
      end

      # Record +command+. +command+ should be a method name and arguments.
      # For example:
      #
      #   recorder.record(:method_name, [:arg1, :arg2])
      def record(*command, &block)
        if @reverting
          @commands << inverse_of(*command, &block)
        else
          @commands << (command << block)
        end
      end

      # Returns the inverse of the given command. For example:
      #
      #   recorder.inverse_of(:rename_table, [:old, :new])
      #   # => [:rename_table, [:new, :old]]
      #
      # If the inverse of a command requires several commands, returns array of commands.
      #
      #   recorder.inverse_of(:remove_columns, [:some_table, :foo, :bar, type: :string])
      #   # => [[:add_column, :some_table, :foo, :string], [:add_column, :some_table, :bar, :string]]
      #
      # This method will raise an +IrreversibleMigration+ exception if it cannot
      # invert the +command+.
      def inverse_of(command, args, &block)
        method = :"invert_#{command}"
        raise IrreversibleMigration, <<~MSG unless respond_to?(method, true)
          This migration uses #{command}, which is not automatically reversible.
          To make the migration reversible you can either:
          1. Define #up and #down methods in place of the #change method.
          2. Use the #reversible method to define reversible behavior.
        MSG
        send(method, args, &block)
      end

      ReversibleAndIrreversibleMethods.each do |method|
        class_eval <<-EOV, __FILE__, __LINE__ + 1
          def #{method}(*args, &block)          # def create_table(*args, &block)
            record(:"#{method}", args, &block)  #   record(:create_table, args, &block)
          end                                   # end
        EOV
        ruby2_keywords(method)
      end
      alias :add_belongs_to :add_reference
      alias :remove_belongs_to :remove_reference

      def change_table(table_name, **options) # :nodoc:
        yield delegate.update_table_definition(table_name, self)
      end

      def replay(migration)
        commands.each do |cmd, args, block|
          migration.send(cmd, *args, &block)
        end
      end

      private
        module StraightReversions # :nodoc:
          private
            {
              execute_block:     :execute_block,
              create_table:      :drop_table,
              create_join_table: :drop_join_table,
              add_column:        :remove_column,
              add_index:         :remove_index,
              add_timestamps:    :remove_timestamps,
              add_reference:     :remove_reference,
              add_foreign_key:   :remove_foreign_key,
              add_check_constraint: :remove_check_constraint,
              enable_extension:  :disable_extension
            }.each do |cmd, inv|
              [[inv, cmd], [cmd, inv]].uniq.each do |method, inverse|
                class_eval <<-EOV, __FILE__, __LINE__ + 1
                  def invert_#{method}(args, &block)    # def invert_create_table(args, &block)
                    [:#{inverse}, args, block]          #   [:drop_table, args, block]
                  end                                   # end
                EOV
              end
            end
        end

        include StraightReversions

        def invert_transaction(args, &block)
          sub_recorder = CommandRecorder.new(delegate)
          sub_recorder.revert(&block)

          invertions_proc = proc {
            sub_recorder.replay(self)
          }

          [:transaction, args, invertions_proc]
        end

        def invert_drop_table(args, &block)
          if args.size == 1 && block == nil
            raise ActiveRecord::IrreversibleMigration, "To avoid mistakes, drop_table is only reversible if given options or a block (can be empty)."
          end
          super
        end

        def invert_rename_table(args)
          [:rename_table, args.reverse]
        end

        def invert_remove_column(args)
          raise ActiveRecord::IrreversibleMigration, "remove_column is only reversible if given a type." if args.size <= 2
          super
        end

        def invert_remove_columns(args)
          unless args[-1].is_a?(Hash) && args[-1].has_key?(:type)
            raise ActiveRecord::IrreversibleMigration, "remove_columns is only reversible if given a type."
          end

          [:add_columns, args]
        end

        def invert_rename_index(args)
          table_name, old_name, new_name = args
          [:rename_index, [table_name, new_name, old_name]]
        end

        def invert_rename_column(args)
          table_name, old_name, new_name = args
          [:rename_column, [table_name, new_name, old_name]]
        end

        def invert_remove_index(args)
          options = args.extract_options!
          table, columns = args

          columns ||= options.delete(:column)

          unless columns
            raise ActiveRecord::IrreversibleMigration, "remove_index is only reversible if given a :column option."
          end

          options.delete(:if_exists)

          args = [table, columns]
          args << options unless options.empty?

          [:add_index, args]
        end

        alias :invert_add_belongs_to :invert_add_reference
        alias :invert_remove_belongs_to :invert_remove_reference

        def invert_change_column_default(args)
          table, column, options = args

          unless options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
            raise ActiveRecord::IrreversibleMigration, "change_column_default is only reversible if given a :from and :to option."
          end

          [:change_column_default, [table, column, from: options[:to], to: options[:from]]]
        end

        def invert_change_column_null(args)
          args[2] = !args[2]
          [:change_column_null, args]
        end

        def invert_remove_foreign_key(args)
          options = args.extract_options!
          from_table, to_table = args

          to_table ||= options.delete(:to_table)

          raise ActiveRecord::IrreversibleMigration, "remove_foreign_key is only reversible if given a second table" if to_table.nil?

          reversed_args = [from_table, to_table]
          reversed_args << options unless options.empty?

          [:add_foreign_key, reversed_args]
        end

        def invert_change_column_comment(args)
          table, column, options = args

          unless options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
            raise ActiveRecord::IrreversibleMigration, "change_column_comment is only reversible if given a :from and :to option."
          end

          [:change_column_comment, [table, column, from: options[:to], to: options[:from]]]
        end

        def invert_change_table_comment(args)
          table, options = args

          unless options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
            raise ActiveRecord::IrreversibleMigration, "change_table_comment is only reversible if given a :from and :to option."
          end

          [:change_table_comment, [table, from: options[:to], to: options[:from]]]
        end

        def invert_remove_check_constraint(args)
          raise ActiveRecord::IrreversibleMigration, "remove_check_constraint is only reversible if given an expression." if args.size < 2
          super
        end

        def respond_to_missing?(method, _)
          super || delegate.respond_to?(method)
        end

        # Forwards any missing method call to the \target.
        def method_missing(method, *args, &block)
          if delegate.respond_to?(method)
            delegate.public_send(method, *args, &block)
          else
            super
          end
        end
        ruby2_keywords(:method_missing)
    end
  end
end

comment.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Comment < Arel::Nodes::Node
      attr_reader :values

      def initialize(values)
        super()
        @values = values
      end

      def initialize_copy(other)
        super
        @values = @values.clone
      end

      def hash
        [@values].hash
      end

      def eql?(other)
        self.class == other.class &&
          self.values == other.values
      end
      alias :== :eql?
    end
  end
end

compatibility.rb

# frozen_string_literal: true

module ActiveRecord
  class Migration
    module Compatibility # :nodoc: all
      def self.find(version)
        version = version.to_s
        name = "V#{version.tr('.', '_')}"
        unless const_defined?(name)
          versions = constants.grep(/\AV[0-9_]+\z/).map { |s| s.to_s.delete("V").tr("_", ".").inspect }
          raise ArgumentError, "Unknown migration version #{version.inspect}; expected one of #{versions.sort.join(', ')}"
        end
        const_get(name)
      end

      # This file exists to ensure that old migrations run the same way they did before a Rails upgrade.
      # e.g. if you write a migration on Rails 6.1, then upgrade to Rails 7, the migration should do the same thing to your
      # database as it did when you were running Rails 6.1
      #
      # "Current" is an alias for `ActiveRecord::Migration`, it represents the current Rails version.
      # New migration functionality that will never be backward compatible should be added directly to `ActiveRecord::Migration`.
      #
      # There are classes for each prior Rails version. Each class descends from the *next* Rails version, so:
      # 7.0 < 7.1
      # 5.2 < 6.0 < 6.1 < 7.0 < 7.1
      #
      # If you are introducing new migration functionality that should only apply from Rails 7 onward, then you should
      # find the class that immediately precedes it (6.1), and override the relevant migration methods to undo your changes.
      #
      # For example, Rails 6 added a default value for the `precision` option on datetime columns. So in this file, the `V5_2`
      # class sets the value of `precision` to `nil` if it's not explicitly provided. This way, the default value will not apply
      # for migrations written for 5.2, but will for migrations written for 6.0.
      V7_1 = Current

      class V7_0 < V7_1
        module TableDefinition
          private
            def raise_on_if_exist_options(options)
            end
        end

        def create_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def change_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        private
          def compatible_table_definition(t)
            class << t
              prepend TableDefinition
            end
            t
          end
      end

      class V6_1 < V7_0
        class PostgreSQLCompat
          def self.compatible_timestamp_type(type, connection)
            if connection.adapter_name == "PostgreSQL"
              # For Rails <= 6.1, :datetime was aliased to :timestamp
              # See: https://github.com/rails/rails/blob/v6.1.3.2/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb#L108
              # From Rails 7 onwards, you can define what :datetime resolves to (the default is still :timestamp)
              # See `ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.datetime_type`
              type.to_sym == :datetime ? :timestamp : type
            else
              type
            end
          end
        end

        def add_column(table_name, column_name, type, **options)
          if type == :datetime
            options[:precision] ||= nil
          end

          type = PostgreSQLCompat.compatible_timestamp_type(type, connection)
          super
        end

        def create_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def change_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        module TableDefinition
          def new_column_definition(name, type, **options)
            type = PostgreSQLCompat.compatible_timestamp_type(type, @conn)
            super
          end

          def column(name, type, index: nil, **options)
            options[:precision] ||= nil
            super
          end

          private
            def raise_on_if_exist_options(options)
            end
        end

        private
          def compatible_table_definition(t)
            class << t
              prepend TableDefinition
            end
            t
          end
      end

      class V6_0 < V6_1
        class ReferenceDefinition < ConnectionAdapters::ReferenceDefinition
          def index_options(table_name)
            as_options(index)
          end
        end

        module SQLite3
          module TableDefinition
            def references(*args, **options)
              args.each do |ref_name|
                ReferenceDefinition.new(ref_name, type: :integer, **options).add_to(self)
              end
            end
            alias :belongs_to :references

            def column(name, type, index: nil, **options)
              options[:precision] ||= nil
              super
            end
          end
        end

        module TableDefinition
          def references(*args, **options)
            args.each do |ref_name|
              ReferenceDefinition.new(ref_name, **options).add_to(self)
            end
          end
          alias :belongs_to :references

          def column(name, type, index: nil, **options)
            options[:precision] ||= nil
            super
          end

          private
            def raise_on_if_exist_options(options)
            end
        end

        def create_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def change_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def create_join_table(table_1, table_2, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def add_reference(table_name, ref_name, **options)
          if connection.adapter_name == "SQLite"
            reference_definition = ReferenceDefinition.new(ref_name, type: :integer, **options)
          else
            reference_definition = ReferenceDefinition.new(ref_name, **options)
          end

          reference_definition.add_to(connection.update_table_definition(table_name, self))
        end
        alias :add_belongs_to :add_reference

        private
          def compatible_table_definition(t)
            class << t
              prepend TableDefinition
              prepend SQLite3::TableDefinition
            end
            t
          end
      end

      class V5_2 < V6_0
        module TableDefinition
          def timestamps(**options)
            options[:precision] ||= nil
            super
          end

          def column(name, type, index: nil, **options)
            options[:precision] ||= nil
            super
          end

          private
            def raise_on_if_exist_options(options)
            end
        end

        module CommandRecorder
          def invert_transaction(args, &block)
            [:transaction, args, block]
          end

          def invert_change_column_comment(args)
            [:change_column_comment, args]
          end

          def invert_change_table_comment(args)
            [:change_table_comment, args]
          end
        end

        def create_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def change_table(table_name, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def create_join_table(table_1, table_2, **options)
          if block_given?
            super { |t| yield compatible_table_definition(t) }
          else
            super
          end
        end

        def add_timestamps(table_name, **options)
          options[:precision] ||= nil
          super
        end

        private
          def compatible_table_definition(t)
            class << t
              prepend TableDefinition
            end
            t
          end

          def command_recorder
            recorder = super
            class << recorder
              prepend CommandRecorder
            end
            recorder
          end
      end

      class V5_1 < V5_2
        def change_column(table_name, column_name, type, **options)
          if connection.adapter_name == "PostgreSQL"
            super(table_name, column_name, type, **options.except(:default, :null, :comment))
            connection.change_column_default(table_name, column_name, options[:default]) if options.key?(:default)
            connection.change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
            connection.change_column_comment(table_name, column_name, options[:comment]) if options.key?(:comment)
          else
            super
          end
        end

        def create_table(table_name, **options)
          if connection.adapter_name == "Mysql2"
            super(table_name, options: "ENGINE=InnoDB", **options)
          else
            super
          end
        end
      end

      class V5_0 < V5_1
        module TableDefinition
          def primary_key(name, type = :primary_key, **options)
            type = :integer if type == :primary_key
            super
          end

          def references(*args, **options)
            super(*args, type: :integer, **options)
          end
          alias :belongs_to :references

          private
            def raise_on_if_exist_options(options)
            end
        end

        def create_table(table_name, **options)
          if connection.adapter_name == "PostgreSQL"
            if options[:id] == :uuid && !options.key?(:default)
              options[:default] = "uuid_generate_v4()"
            end
          end

          unless connection.adapter_name == "Mysql2" && options[:id] == :bigint
            if [:integer, :bigint].include?(options[:id]) && !options.key?(:default)
              options[:default] = nil
            end
          end

          # Since 5.1 PostgreSQL adapter uses bigserial type for primary
          # keys by default and MySQL uses bigint. This compat layer makes old migrations utilize
          # serial/int type instead -- the way it used to work before 5.1.
          unless options.key?(:id)
            options[:id] = :integer
          end

          super
        end

        def create_join_table(table_1, table_2, column_options: {}, **options)
          column_options.reverse_merge!(type: :integer)
          super
        end

        def add_column(table_name, column_name, type, **options)
          if type == :primary_key
            type = :integer
            options[:primary_key] = true
          elsif type == :datetime
            options[:precision] ||= nil
          end
          super
        end

        def add_reference(table_name, ref_name, **options)
          super(table_name, ref_name, type: :integer, **options)
        end
        alias :add_belongs_to :add_reference

        private
          def compatible_table_definition(t)
            class << t
              prepend TableDefinition
            end
            super
          end
      end

      class V4_2 < V5_0
        module TableDefinition
          def references(*, **options)
            options[:index] ||= false
            super
          end
          alias :belongs_to :references

          def timestamps(**options)
            options[:null] = true if options[:null].nil?
            super
          end

          private
            def raise_on_if_exist_options(options)
            end
        end

        def add_reference(table_name, ref_name, **options)
          options[:index] ||= false
          super
        end
        alias :add_belongs_to :add_reference

        def add_timestamps(table_name, **options)
          options[:null] = true if options[:null].nil?
          super
        end

        def index_exists?(table_name, column_name, **options)
          column_names = Array(column_name).map(&:to_s)
          options[:name] =
            if options[:name].present?
              options[:name].to_s
            else
              connection.index_name(table_name, column: column_names)
            end
          super
        end

        def remove_index(table_name, column_name = nil, **options)
          options[:name] = index_name_for_remove(table_name, column_name, options)
          super
        end

        private
          def compatible_table_definition(t)
            class << t
              prepend TableDefinition
            end
            super
          end

          def index_name_for_remove(table_name, column_name, options)
            index_name = connection.index_name(table_name, column_name || options)

            unless connection.index_name_exists?(table_name, index_name)
              if options.key?(:name)
                options_without_column = options.except(:column)
                index_name_without_column = connection.index_name(table_name, options_without_column)

                if connection.index_name_exists?(table_name, index_name_without_column)
                  return index_name_without_column
                end
              end

              raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist"
            end

            index_name
          end
      end
    end
  end
end

composite.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Collectors
    class Composite
      attr_accessor :preparable

      def initialize(left, right)
        @left = left
        @right = right
      end

      def <<(str)
        left << str
        right << str
        self
      end

      def add_bind(bind, &block)
        left.add_bind bind, &block
        right.add_bind bind, &block
        self
      end

      def add_binds(binds, proc_for_binds = nil, &block)
        left.add_binds(binds, proc_for_binds, &block)
        right.add_binds(binds, proc_for_binds, &block)
        self
      end

      def value
        [left.value, right.value]
      end

      private
        attr_reader :left, :right
    end
  end
end

config.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # Container of configuration options
    class Config
      attr_accessor :primary_key, :deterministic_key, :store_key_references, :key_derivation_salt,
                    :support_unencrypted_data, :encrypt_fixtures, :validate_column_size, :add_to_filter_parameters,
                    :excluded_from_filter_parameters, :extend_queries, :previous_schemes, :forced_encoding_for_deterministic_encryption

      def initialize
        set_defaults
      end

      # Configure previous encryption schemes.
      #
      #   config.active_record.encryption.previous = [ { key_provider: MyOldKeyProvider.new } ]
      def previous=(previous_schemes_properties)
        previous_schemes_properties.each do |properties|
          add_previous_scheme(**properties)
        end
      end

      %w(key_derivation_salt primary_key deterministic_key).each do |key|
        silence_redefinition_of_method key
        define_method(key) do
          instance_variable_get(:"@#{key}").presence or
            raise Errors::Configuration, "Missing Active Record encryption credential: active_record_encryption.#{key}"
        end
      end

      private
        def set_defaults
          self.store_key_references = false
          self.support_unencrypted_data = false
          self.encrypt_fixtures = false
          self.validate_column_size = true
          self.add_to_filter_parameters = true
          self.excluded_from_filter_parameters = []
          self.previous_schemes = []
          self.forced_encoding_for_deterministic_encryption = Encoding::UTF_8

          # TODO: Setting to false for now as the implementation is a bit experimental
          self.extend_queries = false
        end

        def add_previous_scheme(**properties)
          previous_schemes << ActiveRecord::Encryption::Scheme.new(**properties)
        end
    end
  end
end

configurable.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # Configuration API for ActiveRecord::Encryption
    module Configurable
      extend ActiveSupport::Concern

      included do
        mattr_reader :config, default: Config.new
        mattr_accessor :encrypted_attribute_declaration_listeners
      end

      class_methods do
        # Expose getters for context properties
        Context::PROPERTIES.each do |name|
          delegate name, to: :context
        end

        def configure(primary_key: nil, deterministic_key: nil, key_derivation_salt: nil, **properties) # :nodoc:
          config.primary_key = primary_key
          config.deterministic_key = deterministic_key
          config.key_derivation_salt = key_derivation_salt

          properties.each do |name, value|
            [:context, :config].each do |configurable_object_name|
              configurable_object = ActiveRecord::Encryption.send(configurable_object_name)
              configurable_object.send "#{name}=", value if configurable_object.respond_to?("#{name}=")
            end
          end
        end

        # Register callback to be invoked when an encrypted attribute is declared.
        #
        # === Example:
        #
        #   ActiveRecord::Encryption.on_encrypted_attribute_declared do |klass, attribute_name|
        #     ...
        #   end
        def on_encrypted_attribute_declared(&block)
          self.encrypted_attribute_declaration_listeners ||= Concurrent::Array.new
          self.encrypted_attribute_declaration_listeners << block
        end

        def encrypted_attribute_was_declared(klass, name) # :nodoc:
          self.encrypted_attribute_declaration_listeners&.each do |block|
            block.call(klass, name)
          end
        end

        def install_auto_filtered_parameters_hook(application) # :nodoc:
          ActiveRecord::Encryption.on_encrypted_attribute_declared do |klass, encrypted_attribute_name|
            filter_parameter = [("#{klass.model_name.element}" if klass.name), encrypted_attribute_name.to_s].compact.join(".")
            application.config.filter_parameters << filter_parameter unless excluded_from_filter_parameters?(filter_parameter)
          end
        end

        private
          def excluded_from_filter_parameters?(filter_parameter)
            ActiveRecord::Encryption.config.excluded_from_filter_parameters.find { |excluded_filter| excluded_filter.to_s == filter_parameter }
          end
      end
    end
  end
end

connection.rb

# frozen_string_literal: true

module ActiveRecord
  module TypeCaster
    class Connection # :nodoc:
      def initialize(klass, table_name)
        @klass = klass
        @table_name = table_name
      end

      def type_cast_for_database(attr_name, value)
        type = type_for_attribute(attr_name)
        type.serialize(value)
      end

      def type_for_attribute(attr_name)
        schema_cache = connection.schema_cache

        if schema_cache.data_source_exists?(table_name)
          column = schema_cache.columns_hash(table_name)[attr_name.to_s]
          type = connection.lookup_cast_type_from_column(column) if column
        end

        type || Type.default_value
      end

      delegate :connection, to: :@klass, private: true

      private
        attr_reader :table_name
    end
  end
end

connection_adapters.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    extend ActiveSupport::Autoload

    eager_autoload do
      autoload :AbstractAdapter
    end

    autoload :Column
    autoload :PoolConfig
    autoload :PoolManager
    autoload :LegacyPoolManager
    autoload :SchemaCache
    autoload :Deduplicable

    autoload_at "active_record/connection_adapters/abstract/schema_definitions" do
      autoload :IndexDefinition
      autoload :ColumnDefinition
      autoload :ChangeColumnDefinition
      autoload :ForeignKeyDefinition
      autoload :CheckConstraintDefinition
      autoload :TableDefinition
      autoload :Table
      autoload :AlterTable
      autoload :ReferenceDefinition
    end

    autoload_under "abstract" do
      autoload :SchemaStatements
      autoload :DatabaseStatements
      autoload :DatabaseLimits
      autoload :Quoting
      autoload :ConnectionHandler
      autoload :QueryCache
      autoload :Savepoints
    end

    autoload_at "active_record/connection_adapters/abstract/connection_pool" do
      autoload :ConnectionPool
      autoload :NullPool
    end

    autoload_at "active_record/connection_adapters/abstract/transaction" do
      autoload :TransactionManager
      autoload :NullTransaction
      autoload :RealTransaction
      autoload :SavepointTransaction
      autoload :TransactionState
    end
  end
end

connection_handler.rb

# frozen_string_literal: true

require "thread"
require "concurrent/map"

module ActiveRecord
  module ConnectionAdapters
    # ConnectionHandler is a collection of ConnectionPool objects. It is used
    # for keeping separate connection pools that connect to different databases.
    #
    # For example, suppose that you have 5 models, with the following hierarchy:
    #
    #   class Author < ActiveRecord::Base
    #   end
    #
    #   class BankAccount < ActiveRecord::Base
    #   end
    #
    #   class Book < ActiveRecord::Base
    #     establish_connection :library_db
    #   end
    #
    #   class ScaryBook < Book
    #   end
    #
    #   class GoodBook < Book
    #   end
    #
    # And a database.yml that looked like this:
    #
    #   development:
    #     database: my_application
    #     host: localhost
    #
    #   library_db:
    #     database: library
    #     host: some.library.org
    #
    # Your primary database in the development environment is "my_application"
    # but the Book model connects to a separate database called "library_db"
    # (this can even be a database on a different machine).
    #
    # Book, ScaryBook, and GoodBook will all use the same connection pool to
    # "library_db" while Author, BankAccount, and any other models you create
    # will use the default connection pool to "my_application".
    #
    # The various connection pools are managed by a single instance of
    # ConnectionHandler accessible via ActiveRecord::Base.connection_handler.
    # All Active Record models use this handler to determine the connection pool that they
    # should use.
    #
    # The ConnectionHandler class is not coupled with the Active models, as it has no knowledge
    # about the model. The model needs to pass a connection specification name to the handler,
    # in order to look up the correct connection pool.
    class ConnectionHandler
      FINALIZER = lambda { |_| ActiveSupport::ForkTracker.check! }
      private_constant :FINALIZER

      class StringConnectionOwner # :nodoc:
        attr_reader :name

        def initialize(name)
          @name = name
        end

        def primary_class?
          false
        end

        def current_preventing_writes
          false
        end
      end

      def initialize
        # These caches are keyed by pool_config.connection_specification_name (PoolConfig#connection_specification_name).
        @owner_to_pool_manager = Concurrent::Map.new(initial_capacity: 2)

        # Backup finalizer: if the forked child skipped Kernel#fork the early discard has not occurred
        ObjectSpace.define_finalizer self, FINALIZER
      end

      def prevent_writes # :nodoc:
        ActiveSupport::IsolatedExecutionState[:active_record_prevent_writes]
      end

      def prevent_writes=(prevent_writes) # :nodoc:
        ActiveSupport::IsolatedExecutionState[:active_record_prevent_writes] = prevent_writes
      end

      # Prevent writing to the database regardless of role.
      #
      # In some cases you may want to prevent writes to the database
      # even if you are on a database that can write. +while_preventing_writes+
      # will prevent writes to the database for the duration of the block.
      #
      # This method does not provide the same protection as a readonly
      # user and is meant to be a safeguard against accidental writes.
      #
      # See +READ_QUERY+ for the queries that are blocked by this
      # method.
      def while_preventing_writes(enabled = true)
        unless ActiveRecord.legacy_connection_handling
          raise NotImplementedError, "`while_preventing_writes` is only available on the connection_handler with legacy_connection_handling"
        end

        original, self.prevent_writes = self.prevent_writes, enabled
        yield
      ensure
        self.prevent_writes = original
      end

      def connection_pool_names # :nodoc:
        owner_to_pool_manager.keys
      end

      def all_connection_pools
        owner_to_pool_manager.values.flat_map { |m| m.pool_configs.map(&:pool) }
      end

      def connection_pool_list(role = ActiveRecord::Base.current_role)
        owner_to_pool_manager.values.flat_map { |m| m.pool_configs(role).map(&:pool) }
      end
      alias :connection_pools :connection_pool_list

      def establish_connection(config, owner_name: Base, role: ActiveRecord::Base.current_role, shard: Base.current_shard)
        owner_name = StringConnectionOwner.new(config.to_s) if config.is_a?(Symbol)

        pool_config = resolve_pool_config(config, owner_name, role, shard)
        db_config = pool_config.db_config

        # Protects the connection named `ActiveRecord::Base` from being removed
        # if the user calls `establish_connection :primary`.
        if owner_to_pool_manager.key?(pool_config.connection_specification_name)
          remove_connection_pool(pool_config.connection_specification_name, role: role, shard: shard)
        end

        message_bus = ActiveSupport::Notifications.instrumenter
        payload = {}
        if pool_config
          payload[:spec_name] = pool_config.connection_specification_name
          payload[:shard] = shard
          payload[:config] = db_config.configuration_hash
        end

        if ActiveRecord.legacy_connection_handling
          owner_to_pool_manager[pool_config.connection_specification_name] ||= LegacyPoolManager.new
        else
          owner_to_pool_manager[pool_config.connection_specification_name] ||= PoolManager.new
        end
        pool_manager = get_pool_manager(pool_config.connection_specification_name)
        pool_manager.set_pool_config(role, shard, pool_config)

        message_bus.instrument("!connection.active_record", payload) do
          pool_config.pool
        end
      end

      # Returns true if there are any active connections among the connection
      # pools that the ConnectionHandler is managing.
      def active_connections?(role = ActiveRecord::Base.current_role)
        connection_pool_list(role).any?(&:active_connection?)
      end

      # Returns any connections in use by the current thread back to the pool,
      # and also returns connections to the pool cached by threads that are no
      # longer alive.
      def clear_active_connections!(role = ActiveRecord::Base.current_role)
        connection_pool_list(role).each(&:release_connection)
      end

      # Clears the cache which maps classes.
      #
      # See ConnectionPool#clear_reloadable_connections! for details.
      def clear_reloadable_connections!(role = ActiveRecord::Base.current_role)
        connection_pool_list(role).each(&:clear_reloadable_connections!)
      end

      def clear_all_connections!(role = ActiveRecord::Base.current_role)
        connection_pool_list(role).each(&:disconnect!)
      end

      # Disconnects all currently idle connections.
      #
      # See ConnectionPool#flush! for details.
      def flush_idle_connections!(role = ActiveRecord::Base.current_role)
        connection_pool_list(role).each(&:flush!)
      end

      # Locate the connection of the nearest super class. This can be an
      # active or defined connection: if it is the latter, it will be
      # opened and set as the active connection for the class it was defined
      # for (not necessarily the current class).
      def retrieve_connection(spec_name, role: ActiveRecord::Base.current_role, shard: ActiveRecord::Base.current_shard) # :nodoc:
        pool = retrieve_connection_pool(spec_name, role: role, shard: shard)

        unless pool
          if shard != ActiveRecord::Base.default_shard
            message = "No connection pool for '#{spec_name}' found for the '#{shard}' shard."
          elsif ActiveRecord::Base.connection_handler != ActiveRecord::Base.default_connection_handler
            message = "No connection pool for '#{spec_name}' found for the '#{ActiveRecord::Base.current_role}' role."
          elsif role != ActiveRecord::Base.default_role
            message = "No connection pool for '#{spec_name}' found for the '#{role}' role."
          else
            message = "No connection pool for '#{spec_name}' found."
          end

          raise ConnectionNotEstablished, message
        end

        pool.connection
      end

      # Returns true if a connection that's accessible to this class has
      # already been opened.
      def connected?(spec_name, role: ActiveRecord::Base.current_role, shard: ActiveRecord::Base.current_shard)
        pool = retrieve_connection_pool(spec_name, role: role, shard: shard)
        pool && pool.connected?
      end

      def remove_connection_pool(owner, role: ActiveRecord::Base.current_role, shard: ActiveRecord::Base.current_shard)
        if pool_manager = get_pool_manager(owner)
          pool_config = pool_manager.remove_pool_config(role, shard)

          if pool_config
            pool_config.disconnect!
            pool_config.db_config
          end
        end
      end

      # Retrieving the connection pool happens a lot, so we cache it in @owner_to_pool_manager.
      # This makes retrieving the connection pool O(1) once the process is warm.
      # When a connection is established or removed, we invalidate the cache.
      def retrieve_connection_pool(owner, role: ActiveRecord::Base.current_role, shard: ActiveRecord::Base.current_shard)
        pool_config = get_pool_manager(owner)&.get_pool_config(role, shard)
        pool_config&.pool
      end

      private
        attr_reader :owner_to_pool_manager

        # Returns the pool manager for an owner.
        def get_pool_manager(owner)
          owner_to_pool_manager[owner]
        end

        # Returns an instance of PoolConfig for a given adapter.
        # Accepts a hash one layer deep that contains all connection information.
        #
        # == Example
        #
        #   config = { "production" => { "host" => "localhost", "database" => "foo", "adapter" => "sqlite3" } }
        #   pool_config = Base.configurations.resolve_pool_config(:production)
        #   pool_config.db_config.configuration_hash
        #   # => { host: "localhost", database: "foo", adapter: "sqlite3" }
        #
        def resolve_pool_config(config, owner_name, role, shard)
          db_config = Base.configurations.resolve(config)

          raise(AdapterNotSpecified, "database configuration does not specify adapter") unless db_config.adapter

          # Require the adapter itself and give useful feedback about
          #   1. Missing adapter gems and
          #   2. Adapter gems' missing dependencies.
          path_to_adapter = "active_record/connection_adapters/#{db_config.adapter}_adapter"
          begin
            require path_to_adapter
          rescue LoadError => e
            # We couldn't require the adapter itself. Raise an exception that
            # points out config typos and missing gems.
            if e.path == path_to_adapter
              # We can assume that a non-builtin adapter was specified, so it's
              # either misspelled or missing from Gemfile.
              raise LoadError, "Could not load the '#{db_config.adapter}' Active Record adapter. Ensure that the adapter is spelled correctly in config/database.yml and that you've added the necessary adapter gem to your Gemfile.", e.backtrace

              # Bubbled up from the adapter require. Prefix the exception message
              # with some guidance about how to address it and reraise.
            else
              raise LoadError, "Error loading the '#{db_config.adapter}' Active Record adapter. Missing a gem it depends on? #{e.message}", e.backtrace
            end
          end

          unless ActiveRecord::Base.respond_to?(db_config.adapter_method)
            raise AdapterNotFound, "database configuration specifies nonexistent #{db_config.adapter} adapter"
          end

          ConnectionAdapters::PoolConfig.new(owner_name, db_config, role, shard)
        end
    end
  end
end

connection_handling.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionHandling
    RAILS_ENV   = -> { (Rails.env if defined?(Rails.env)) || ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence }
    DEFAULT_ENV = -> { RAILS_ENV.call || "default_env" }

    # Establishes the connection to the database. Accepts a hash as input where
    # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
    # example for regular databases (MySQL, PostgreSQL, etc):
    #
    #   ActiveRecord::Base.establish_connection(
    #     adapter:  "mysql2",
    #     host:     "localhost",
    #     username: "myuser",
    #     password: "mypass",
    #     database: "somedatabase"
    #   )
    #
    # Example for SQLite database:
    #
    #   ActiveRecord::Base.establish_connection(
    #     adapter:  "sqlite3",
    #     database: "path/to/dbfile"
    #   )
    #
    # Also accepts keys as strings (for parsing from YAML for example):
    #
    #   ActiveRecord::Base.establish_connection(
    #     "adapter"  => "sqlite3",
    #     "database" => "path/to/dbfile"
    #   )
    #
    # Or a URL:
    #
    #   ActiveRecord::Base.establish_connection(
    #     "postgres://myuser:mypass@localhost/somedatabase"
    #   )
    #
    # In case {ActiveRecord::Base.configurations}[rdoc-ref:Core.configurations]
    # is set (Rails automatically loads the contents of config/database.yml into it),
    # a symbol can also be given as argument, representing a key in the
    # configuration hash:
    #
    #   ActiveRecord::Base.establish_connection(:production)
    #
    # The exceptions AdapterNotSpecified, AdapterNotFound, and +ArgumentError+
    # may be returned on an error.
    def establish_connection(config_or_env = nil)
      config_or_env ||= DEFAULT_ENV.call.to_sym
      db_config, owner_name = resolve_config_for_connection(config_or_env)
      connection_handler.establish_connection(db_config, owner_name: owner_name, role: current_role, shard: current_shard)
    end

    # Connects a model to the databases specified. The +database+ keyword
    # takes a hash consisting of a +role+ and a +database_key+.
    #
    # This will create a connection handler for switching between connections,
    # look up the config hash using the +database_key+ and finally
    # establishes a connection to that config.
    #
    #   class AnimalsModel < ApplicationRecord
    #     self.abstract_class = true
    #
    #     connects_to database: { writing: :primary, reading: :primary_replica }
    #   end
    #
    # +connects_to+ also supports horizontal sharding. The horizontal sharding API
    # also supports read replicas. Connect a model to a list of shards like this:
    #
    #   class AnimalsModel < ApplicationRecord
    #     self.abstract_class = true
    #
    #     connects_to shards: {
    #       default: { writing: :primary, reading: :primary_replica },
    #       shard_two: { writing: :primary_shard_two, reading: :primary_shard_replica_two }
    #     }
    #   end
    #
    # Returns an array of database connections.
    def connects_to(database: {}, shards: {})
      raise NotImplementedError, "`connects_to` can only be called on ActiveRecord::Base or abstract classes" unless self == Base || abstract_class?

      if database.present? && shards.present?
        raise ArgumentError, "`connects_to` can only accept a `database` or `shards` argument, but not both arguments."
      end

      connections = []

      database.each do |role, database_key|
        db_config, owner_name = resolve_config_for_connection(database_key)
        handler = lookup_connection_handler(role.to_sym)

        self.connection_class = true
        connections << handler.establish_connection(db_config, owner_name: owner_name, role: role)
      end

      shards.each do |shard, database_keys|
        database_keys.each do |role, database_key|
          db_config, owner_name = resolve_config_for_connection(database_key)
          handler = lookup_connection_handler(role.to_sym)

          self.connection_class = true
          connections << handler.establish_connection(db_config, owner_name: owner_name, role: role, shard: shard.to_sym)
        end
      end

      connections
    end

    # Connects to a role (e.g. writing, reading, or a custom role) and/or
    # shard for the duration of the block. At the end of the block the
    # connection will be returned to the original role / shard.
    #
    # If only a role is passed, Active Record will look up the connection
    # based on the requested role. If a non-established role is requested
    # an +ActiveRecord::ConnectionNotEstablished+ error will be raised:
    #
    #   ActiveRecord::Base.connected_to(role: :writing) do
    #     Dog.create! # creates dog using dog writing connection
    #   end
    #
    #   ActiveRecord::Base.connected_to(role: :reading) do
    #     Dog.create! # throws exception because we're on a replica
    #   end
    #
    # When swapping to a shard, the role must be passed as well. If a non-existent
    # shard is passed, an +ActiveRecord::ConnectionNotEstablished+ error will be
    # raised.
    #
    # When a shard and role is passed, Active Record will first lookup the role,
    # and then look up the connection by shard key.
    #
    #   ActiveRecord::Base.connected_to(role: :reading, shard: :shard_one_replica) do
    #     Dog.first # finds first Dog record stored on the shard one replica
    #   end
    def connected_to(role: nil, shard: nil, prevent_writes: false, &blk)
      if ActiveRecord.legacy_connection_handling
        if self != Base
          raise NotImplementedError, "`connected_to` can only be called on ActiveRecord::Base with legacy connection handling."
        end
      else
        if self != Base && !abstract_class
          raise NotImplementedError, "calling `connected_to` is only allowed on ActiveRecord::Base or abstract classes."
        end

        if name != connection_specification_name && !primary_class?
          raise NotImplementedError, "calling `connected_to` is only allowed on the abstract class that established the connection."
        end
      end

      unless role || shard
        raise ArgumentError, "must provide a `shard` and/or `role`."
      end

      with_role_and_shard(role, shard, prevent_writes, &blk)
    end

    # Connects a role and/or shard to the provided connection names. Optionally +prevent_writes+
    # can be passed to block writes on a connection. +reading+ will automatically set
    # +prevent_writes+ to true.
    #
    # +connected_to_many+ is an alternative to deeply nested +connected_to+ blocks.
    #
    # Usage:
    #
    #   ActiveRecord::Base.connected_to_many(AnimalsRecord, MealsRecord, role: :reading) do
    #     Dog.first # Read from animals replica
    #     Dinner.first # Read from meals replica
    #     Person.first # Read from primary writer
    #   end
    def connected_to_many(*classes, role:, shard: nil, prevent_writes: false)
      classes = classes.flatten

      if ActiveRecord.legacy_connection_handling
        raise NotImplementedError, "connected_to_many is not available with legacy connection handling"
      end

      if self != Base || classes.include?(Base)
        raise NotImplementedError, "connected_to_many can only be called on ActiveRecord::Base."
      end

      prevent_writes = true if role == ActiveRecord.reading_role

      append_to_connected_to_stack(role: role, shard: shard, prevent_writes: prevent_writes, klasses: classes)
      yield
    ensure
      connected_to_stack.pop
    end

    # Use a specified connection.
    #
    # This method is useful for ensuring that a specific connection is
    # being used. For example, when booting a console in readonly mode.
    #
    # It is not recommended to use this method in a request since it
    # does not yield to a block like +connected_to+.
    def connecting_to(role: default_role, shard: default_shard, prevent_writes: false)
      if ActiveRecord.legacy_connection_handling
        raise NotImplementedError, "`connecting_to` is not available with `legacy_connection_handling`."
      end

      prevent_writes = true if role == ActiveRecord.reading_role

      append_to_connected_to_stack(role: role, shard: shard, prevent_writes: prevent_writes, klasses: [self])
    end

    # Prohibit swapping shards while inside of the passed block.
    #
    # In some cases you may want to be able to swap shards but not allow a
    # nested call to connected_to or connected_to_many to swap again. This
    # is useful in cases you're using sharding to provide per-request
    # database isolation.
    def prohibit_shard_swapping(enabled = true)
      prev_value = ActiveSupport::IsolatedExecutionState[:active_record_prohibit_shard_swapping]
      ActiveSupport::IsolatedExecutionState[:active_record_prohibit_shard_swapping] = enabled
      yield
    ensure
      ActiveSupport::IsolatedExecutionState[:active_record_prohibit_shard_swapping] = prev_value
    end

    # Determine whether or not shard swapping is currently prohibited
    def shard_swapping_prohibited?
      ActiveSupport::IsolatedExecutionState[:active_record_prohibit_shard_swapping]
    end

    # Prevent writing to the database regardless of role.
    #
    # In some cases you may want to prevent writes to the database
    # even if you are on a database that can write. +while_preventing_writes+
    # will prevent writes to the database for the duration of the block.
    #
    # This method does not provide the same protection as a readonly
    # user and is meant to be a safeguard against accidental writes.
    #
    # See +READ_QUERY+ for the queries that are blocked by this
    # method.
    def while_preventing_writes(enabled = true, &block)
      if ActiveRecord.legacy_connection_handling
        connection_handler.while_preventing_writes(enabled, &block)
      else
        connected_to(role: current_role, prevent_writes: enabled, &block)
      end
    end

    # Returns true if role is the current connected role.
    #
    #   ActiveRecord::Base.connected_to(role: :writing) do
    #     ActiveRecord::Base.connected_to?(role: :writing) #=> true
    #     ActiveRecord::Base.connected_to?(role: :reading) #=> false
    #   end
    def connected_to?(role:, shard: ActiveRecord::Base.default_shard)
      current_role == role.to_sym && current_shard == shard.to_sym
    end

    def lookup_connection_handler(handler_key) # :nodoc:
      if ActiveRecord.legacy_connection_handling
        handler_key ||= ActiveRecord.writing_role
        connection_handlers[handler_key] ||= ActiveRecord::ConnectionAdapters::ConnectionHandler.new
      else
        ActiveRecord::Base.connection_handler
      end
    end

    # Clears the query cache for all connections associated with the current thread.
    def clear_query_caches_for_current_thread
      if ActiveRecord.legacy_connection_handling
        ActiveRecord::Base.connection_handlers.each_value do |handler|
          clear_on_handler(handler)
        end
      else
        clear_on_handler(ActiveRecord::Base.connection_handler)
      end
    end

    # Returns the connection currently associated with the class. This can
    # also be used to "borrow" the connection to do database work unrelated
    # to any of the specific Active Records.
    def connection
      retrieve_connection
    end

    attr_writer :connection_specification_name

    # Return the connection specification name from the current class or its parent.
    def connection_specification_name
      if !defined?(@connection_specification_name) || @connection_specification_name.nil?
        return self == Base ? Base.name : superclass.connection_specification_name
      end
      @connection_specification_name
    end

    def primary_class? # :nodoc:
      self == Base || application_record_class?
    end

    # Returns the db_config object from the associated connection:
    #
    #  ActiveRecord::Base.connection_db_config
    #    #<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbded10 @env_name="development",
    #      @name="primary", @config={pool: 5, timeout: 5000, database: "db/development.sqlite3", adapter: "sqlite3"}>
    #
    # Use only for reading.
    def connection_db_config
      connection_pool.db_config
    end

    def connection_pool
      connection_handler.retrieve_connection_pool(connection_specification_name, role: current_role, shard: current_shard) || raise(ConnectionNotEstablished)
    end

    def retrieve_connection
      connection_handler.retrieve_connection(connection_specification_name, role: current_role, shard: current_shard)
    end

    # Returns +true+ if Active Record is connected.
    def connected?
      connection_handler.connected?(connection_specification_name, role: current_role, shard: current_shard)
    end

    def remove_connection(name = nil)
      name ||= @connection_specification_name if defined?(@connection_specification_name)
      # if removing a connection that has a pool, we reset the
      # connection_specification_name so it will use the parent
      # pool.
      if connection_handler.retrieve_connection_pool(name, role: current_role, shard: current_shard)
        self.connection_specification_name = nil
      end

      connection_handler.remove_connection_pool(name, role: current_role, shard: current_shard)
    end

    def clear_cache! # :nodoc:
      connection.schema_cache.clear!
    end

    delegate :clear_active_connections!, :clear_reloadable_connections!,
      :clear_all_connections!, :flush_idle_connections!, to: :connection_handler

    private
      def clear_on_handler(handler)
        handler.all_connection_pools.each do |pool|
          pool.connection.clear_query_cache if pool.active_connection?
        end
      end

      def resolve_config_for_connection(config_or_env)
        raise "Anonymous class is not allowed." unless name

        owner_name = primary_class? ? Base.name : name
        self.connection_specification_name = owner_name

        db_config = Base.configurations.resolve(config_or_env)
        [db_config, self]
      end

      def with_handler(handler_key, &blk)
        handler = lookup_connection_handler(handler_key)
        swap_connection_handler(handler, &blk)
      end

      def with_role_and_shard(role, shard, prevent_writes)
        prevent_writes = true if role == ActiveRecord.reading_role

        if ActiveRecord.legacy_connection_handling
          with_handler(role.to_sym) do
            connection_handler.while_preventing_writes(prevent_writes) do
              append_to_connected_to_stack(shard: shard, klasses: [self])
              yield
            end
          end
        else
          append_to_connected_to_stack(role: role, shard: shard, prevent_writes: prevent_writes, klasses: [self])
          return_value = yield
          return_value.load if return_value.is_a? ActiveRecord::Relation
          return_value
        end
      ensure
        self.connected_to_stack.pop
      end

      def append_to_connected_to_stack(entry)
        if shard_swapping_prohibited? && entry[:shard].present?
          raise ArgumentError, "cannot swap `shard` while shard swapping is prohibited."
        end

        connected_to_stack << entry
      end

      def swap_connection_handler(handler, &blk) # :nodoc:
        old_handler, ActiveRecord::Base.connection_handler = ActiveRecord::Base.connection_handler, handler
        return_value = yield
        return_value.load if return_value.is_a? ActiveRecord::Relation
        return_value
      ensure
        ActiveRecord::Base.connection_handler = old_handler
      end
  end
end

connection_pool.rb

# frozen_string_literal: true

require "thread"
require "concurrent/map"
require "monitor"

require "active_record/connection_adapters/abstract/connection_pool/queue"
require "active_record/connection_adapters/abstract/connection_pool/reaper"

module ActiveRecord
  module ConnectionAdapters
    module AbstractPool # :nodoc:
      def get_schema_cache(connection)
        self.schema_cache ||= SchemaCache.new(connection)
        schema_cache.connection = connection
        schema_cache
      end

      def set_schema_cache(cache)
        self.schema_cache = cache
      end

      def lazily_set_schema_cache
        return unless ActiveRecord.lazily_load_schema_cache

        cache = SchemaCache.load_from(db_config.lazy_schema_cache_path)
        set_schema_cache(cache)
      end
    end

    class NullPool # :nodoc:
      include ConnectionAdapters::AbstractPool

      attr_accessor :schema_cache

      def connection_class; end
      def checkin(_); end
      def remove(_); end
      def async_executor; end
    end

    # Connection pool base class for managing Active Record database
    # connections.
    #
    # == Introduction
    #
    # A connection pool synchronizes thread access to a limited number of
    # database connections. The basic idea is that each thread checks out a
    # database connection from the pool, uses that connection, and checks the
    # connection back in. ConnectionPool is completely thread-safe, and will
    # ensure that a connection cannot be used by two threads at the same time,
    # as long as ConnectionPool's contract is correctly followed. It will also
    # handle cases in which there are more threads than connections: if all
    # connections have been checked out, and a thread tries to checkout a
    # connection anyway, then ConnectionPool will wait until some other thread
    # has checked in a connection.
    #
    # == Obtaining (checking out) a connection
    #
    # Connections can be obtained and used from a connection pool in several
    # ways:
    #
    # 1. Simply use {ActiveRecord::Base.connection}[rdoc-ref:ConnectionHandling.connection]
    #    as with Active Record 2.1 and
    #    earlier (pre-connection-pooling). Eventually, when you're done with
    #    the connection(s) and wish it to be returned to the pool, you call
    #    {ActiveRecord::Base.clear_active_connections!}[rdoc-ref:ConnectionAdapters::ConnectionHandler#clear_active_connections!].
    #    This will be the default behavior for Active Record when used in conjunction with
    #    Action Pack's request handling cycle.
    # 2. Manually check out a connection from the pool with
    #    {ActiveRecord::Base.connection_pool.checkout}[rdoc-ref:#checkout]. You are responsible for
    #    returning this connection to the pool when finished by calling
    #    {ActiveRecord::Base.connection_pool.checkin(connection)}[rdoc-ref:#checkin].
    # 3. Use {ActiveRecord::Base.connection_pool.with_connection(&block)}[rdoc-ref:#with_connection], which
    #    obtains a connection, yields it as the sole argument to the block,
    #    and returns it to the pool after the block completes.
    #
    # Connections in the pool are actually AbstractAdapter objects (or objects
    # compatible with AbstractAdapter's interface).
    #
    # == Options
    #
    # There are several connection-pooling-related options that you can add to
    # your database connection configuration:
    #
    # * +pool+: maximum number of connections the pool may manage (default 5).
    # * +idle_timeout+: number of seconds that a connection will be kept
    #   unused in the pool before it is automatically disconnected (default
    #   300 seconds). Set this to zero to keep connections forever.
    # * +checkout_timeout+: number of seconds to wait for a connection to
    #   become available before giving up and raising a timeout error (default
    #   5 seconds).
    #
    #--
    # Synchronization policy:
    # * all public methods can be called outside +synchronize+
    # * access to these instance variables needs to be in +synchronize+:
    #   * @connections
    #   * @now_connecting
    # * private methods that require being called in a +synchronize+ blocks
    #   are now explicitly documented
    class ConnectionPool
      include MonitorMixin
      include QueryCache::ConnectionPoolConfiguration
      include ConnectionAdapters::AbstractPool

      attr_accessor :automatic_reconnect, :checkout_timeout
      attr_reader :db_config, :size, :reaper, :pool_config, :connection_class, :async_executor, :role, :shard

      alias_method :connection_klass, :connection_class
      deprecate :connection_klass
      delegate :schema_cache, :schema_cache=, to: :pool_config

      # Creates a new ConnectionPool object. +pool_config+ is a PoolConfig
      # object which describes database connection information (e.g. adapter,
      # host name, username, password, etc), as well as the maximum size for
      # this ConnectionPool.
      #
      # The default ConnectionPool maximum size is 5.
      def initialize(pool_config)
        super()

        @pool_config = pool_config
        @db_config = pool_config.db_config
        @connection_class = pool_config.connection_class
        @role = pool_config.role
        @shard = pool_config.shard

        @checkout_timeout = db_config.checkout_timeout
        @idle_timeout = db_config.idle_timeout
        @size = db_config.pool

        # This variable tracks the cache of threads mapped to reserved connections, with the
        # sole purpose of speeding up the +connection+ method. It is not the authoritative
        # registry of which thread owns which connection. Connection ownership is tracked by
        # the +connection.owner+ attr on each +connection+ instance.
        # The invariant works like this: if there is mapping of <tt>thread => conn</tt>,
        # then that +thread+ does indeed own that +conn+. However, an absence of such
        # mapping does not mean that the +thread+ doesn't own the said connection. In
        # that case +conn.owner+ attr should be consulted.
        # Access and modification of <tt>@thread_cached_conns</tt> does not require
        # synchronization.
        @thread_cached_conns = Concurrent::Map.new(initial_capacity: @size)

        @connections         = []
        @automatic_reconnect = true

        # Connection pool allows for concurrent (outside the main +synchronize+ section)
        # establishment of new connections. This variable tracks the number of threads
        # currently in the process of independently establishing connections to the DB.
        @now_connecting = 0

        @threads_blocking_new_connections = 0

        @available = ConnectionLeasingQueue.new self

        @lock_thread = false

        @async_executor = build_async_executor

        lazily_set_schema_cache

        @reaper = Reaper.new(self, db_config.reaping_frequency)
        @reaper.run
      end

      def lock_thread=(lock_thread)
        if lock_thread
          @lock_thread = ActiveSupport::IsolatedExecutionState.context
        else
          @lock_thread = nil
        end
      end

      # Retrieve the connection associated with the current thread, or call
      # #checkout to obtain one if necessary.
      #
      # #connection can be called any number of times; the connection is
      # held in a cache keyed by a thread.
      def connection
        @thread_cached_conns[connection_cache_key(current_thread)] ||= checkout
      end

      # Returns true if there is an open connection being used for the current thread.
      #
      # This method only works for connections that have been obtained through
      # #connection or #with_connection methods. Connections obtained through
      # #checkout will not be detected by #active_connection?
      def active_connection?
        @thread_cached_conns[connection_cache_key(current_thread)]
      end

      # Signal that the thread is finished with the current connection.
      # #release_connection releases the connection-thread association
      # and returns the connection to the pool.
      #
      # This method only works for connections that have been obtained through
      # #connection or #with_connection methods, connections obtained through
      # #checkout will not be automatically released.
      def release_connection(owner_thread = ActiveSupport::IsolatedExecutionState.context)
        if conn = @thread_cached_conns.delete(connection_cache_key(owner_thread))
          checkin conn
        end
      end

      # If a connection obtained through #connection or #with_connection methods
      # already exists yield it to the block. If no such connection
      # exists checkout a connection, yield it to the block, and checkin the
      # connection when finished.
      def with_connection
        unless conn = @thread_cached_conns[connection_cache_key(ActiveSupport::IsolatedExecutionState.context)]
          conn = connection
          fresh_connection = true
        end
        yield conn
      ensure
        release_connection if fresh_connection
      end

      # Returns true if a connection has already been opened.
      def connected?
        synchronize { @connections.any? }
      end

      # Returns an array containing the connections currently in the pool.
      # Access to the array does not require synchronization on the pool because
      # the array is newly created and not retained by the pool.
      #
      # However; this method bypasses the ConnectionPool's thread-safe connection
      # access pattern. A returned connection may be owned by another thread,
      # unowned, or by happen-stance owned by the calling thread.
      #
      # Calling methods on a connection without ownership is subject to the
      # thread-safety guarantees of the underlying method. Many of the methods
      # on connection adapter classes are inherently multi-thread unsafe.
      def connections
        synchronize { @connections.dup }
      end

      # Disconnects all connections in the pool, and clears the pool.
      #
      # Raises:
      # - ActiveRecord::ExclusiveConnectionTimeoutError if unable to gain ownership of all
      #   connections in the pool within a timeout interval (default duration is
      #   <tt>spec.db_config.checkout_timeout * 2</tt> seconds).
      def disconnect(raise_on_acquisition_timeout = true)
        with_exclusively_acquired_all_connections(raise_on_acquisition_timeout) do
          synchronize do
            @connections.each do |conn|
              if conn.in_use?
                conn.steal!
                checkin conn
              end
              conn.disconnect!
            end
            @connections = []
            @available.clear
          end
        end
      end

      # Disconnects all connections in the pool, and clears the pool.
      #
      # The pool first tries to gain ownership of all connections. If unable to
      # do so within a timeout interval (default duration is
      # <tt>spec.db_config.checkout_timeout * 2</tt> seconds), then the pool is forcefully
      # disconnected without any regard for other connection owning threads.
      def disconnect!
        disconnect(false)
      end

      # Discards all connections in the pool (even if they're currently
      # leased!), along with the pool itself. Any further interaction with the
      # pool (except #spec and #schema_cache) is undefined.
      #
      # See AbstractAdapter#discard!
      def discard! # :nodoc:
        synchronize do
          return if self.discarded?
          @connections.each do |conn|
            conn.discard!
          end
          @connections = @available = @thread_cached_conns = nil
        end
      end

      def discarded? # :nodoc:
        @connections.nil?
      end

      # Clears the cache which maps classes and re-connects connections that
      # require reloading.
      #
      # Raises:
      # - ActiveRecord::ExclusiveConnectionTimeoutError if unable to gain ownership of all
      #   connections in the pool within a timeout interval (default duration is
      #   <tt>spec.db_config.checkout_timeout * 2</tt> seconds).
      def clear_reloadable_connections(raise_on_acquisition_timeout = true)
        with_exclusively_acquired_all_connections(raise_on_acquisition_timeout) do
          synchronize do
            @connections.each do |conn|
              if conn.in_use?
                conn.steal!
                checkin conn
              end
              conn.disconnect! if conn.requires_reloading?
            end
            @connections.delete_if(&:requires_reloading?)
            @available.clear
          end
        end
      end

      # Clears the cache which maps classes and re-connects connections that
      # require reloading.
      #
      # The pool first tries to gain ownership of all connections. If unable to
      # do so within a timeout interval (default duration is
      # <tt>spec.db_config.checkout_timeout * 2</tt> seconds), then the pool forcefully
      # clears the cache and reloads connections without any regard for other
      # connection owning threads.
      def clear_reloadable_connections!
        clear_reloadable_connections(false)
      end

      # Check-out a database connection from the pool, indicating that you want
      # to use it. You should call #checkin when you no longer need this.
      #
      # This is done by either returning and leasing existing connection, or by
      # creating a new connection and leasing it.
      #
      # If all connections are leased and the pool is at capacity (meaning the
      # number of currently leased connections is greater than or equal to the
      # size limit set), an ActiveRecord::ConnectionTimeoutError exception will be raised.
      #
      # Returns: an AbstractAdapter object.
      #
      # Raises:
      # - ActiveRecord::ConnectionTimeoutError no connection can be obtained from the pool.
      def checkout(checkout_timeout = @checkout_timeout)
        checkout_and_verify(acquire_connection(checkout_timeout))
      end

      # Check-in a database connection back into the pool, indicating that you
      # no longer need this connection.
      #
      # +conn+: an AbstractAdapter object, which was obtained by earlier by
      # calling #checkout on this pool.
      def checkin(conn)
        conn.lock.synchronize do
          synchronize do
            remove_connection_from_thread_cache conn

            conn._run_checkin_callbacks do
              conn.expire
            end

            @available.add conn
          end
        end
      end

      # Remove a connection from the connection pool. The connection will
      # remain open and active but will no longer be managed by this pool.
      def remove(conn)
        needs_new_connection = false

        synchronize do
          remove_connection_from_thread_cache conn

          @connections.delete conn
          @available.delete conn

          # @available.any_waiting? => true means that prior to removing this
          # conn, the pool was at its max size (@connections.size == @size).
          # This would mean that any threads stuck waiting in the queue wouldn't
          # know they could checkout_new_connection, so let's do it for them.
          # Because condition-wait loop is encapsulated in the Queue class
          # (that in turn is oblivious to ConnectionPool implementation), threads
          # that are "stuck" there are helpless. They have no way of creating
          # new connections and are completely reliant on us feeding available
          # connections into the Queue.
          needs_new_connection = @available.any_waiting?
        end

        # This is intentionally done outside of the synchronized section as we
        # would like not to hold the main mutex while checking out new connections.
        # Thus there is some chance that needs_new_connection information is now
        # stale, we can live with that (bulk_make_new_connections will make
        # sure not to exceed the pool's @size limit).
        bulk_make_new_connections(1) if needs_new_connection
      end

      # Recover lost connections for the pool. A lost connection can occur if
      # a programmer forgets to checkin a connection at the end of a thread
      # or a thread dies unexpectedly.
      def reap
        stale_connections = synchronize do
          return if self.discarded?
          @connections.select do |conn|
            conn.in_use? && !conn.owner.alive?
          end.each do |conn|
            conn.steal!
          end
        end

        stale_connections.each do |conn|
          if conn.active?
            conn.reset!
            checkin conn
          else
            remove conn
          end
        end
      end

      # Disconnect all connections that have been idle for at least
      # +minimum_idle+ seconds. Connections currently checked out, or that were
      # checked in less than +minimum_idle+ seconds ago, are unaffected.
      def flush(minimum_idle = @idle_timeout)
        return if minimum_idle.nil?

        idle_connections = synchronize do
          return if self.discarded?
          @connections.select do |conn|
            !conn.in_use? && conn.seconds_idle >= minimum_idle
          end.each do |conn|
            conn.lease

            @available.delete conn
            @connections.delete conn
          end
        end

        idle_connections.each do |conn|
          conn.disconnect!
        end
      end

      # Disconnect all currently idle connections. Connections currently checked
      # out are unaffected.
      def flush!
        reap
        flush(-1)
      end

      def num_waiting_in_queue # :nodoc:
        @available.num_waiting
      end

      # Return connection pool's usage statistic
      # Example:
      #
      #    ActiveRecord::Base.connection_pool.stat # => { size: 15, connections: 1, busy: 1, dead: 0, idle: 0, waiting: 0, checkout_timeout: 5 }
      def stat
        synchronize do
          {
            size: size,
            connections: @connections.size,
            busy: @connections.count { |c| c.in_use? && c.owner.alive? },
            dead: @connections.count { |c| c.in_use? && !c.owner.alive? },
            idle: @connections.count { |c| !c.in_use? },
            waiting: num_waiting_in_queue,
            checkout_timeout: checkout_timeout
          }
        end
      end

      def schedule_query(future_result) # :nodoc:
        @async_executor.post { future_result.execute_or_skip }
        Thread.pass
      end

      private
        def build_async_executor
          case ActiveRecord.async_query_executor
          when :multi_thread_pool
            if @db_config.max_threads > 0
              Concurrent::ThreadPoolExecutor.new(
                min_threads: @db_config.min_threads,
                max_threads: @db_config.max_threads,
                max_queue: @db_config.max_queue,
                fallback_policy: :caller_runs
              )
            end
          when :global_thread_pool
            ActiveRecord.global_thread_pool_async_query_executor
          end
        end

        #--
        # this is unfortunately not concurrent
        def bulk_make_new_connections(num_new_conns_needed)
          num_new_conns_needed.times do
            # try_to_checkout_new_connection will not exceed pool's @size limit
            if new_conn = try_to_checkout_new_connection
              # make the new_conn available to the starving threads stuck @available Queue
              checkin(new_conn)
            end
          end
        end

        #--
        # From the discussion on GitHub:
        #  https://github.com/rails/rails/pull/14938#commitcomment-6601951
        # This hook-in method allows for easier monkey-patching fixes needed by
        # JRuby users that use Fibers.
        def connection_cache_key(thread)
          thread
        end

        def current_thread
          @lock_thread || ActiveSupport::IsolatedExecutionState.context
        end

        # Take control of all existing connections so a "group" action such as
        # reload/disconnect can be performed safely. It is no longer enough to
        # wrap it in +synchronize+ because some pool's actions are allowed
        # to be performed outside of the main +synchronize+ block.
        def with_exclusively_acquired_all_connections(raise_on_acquisition_timeout = true)
          with_new_connections_blocked do
            attempt_to_checkout_all_existing_connections(raise_on_acquisition_timeout)
            yield
          end
        end

        def attempt_to_checkout_all_existing_connections(raise_on_acquisition_timeout = true)
          collected_conns = synchronize do
            # account for our own connections
            @connections.select { |conn| conn.owner == ActiveSupport::IsolatedExecutionState.context }
          end

          newly_checked_out = []
          timeout_time      = Process.clock_gettime(Process::CLOCK_MONOTONIC) + (@checkout_timeout * 2)

          @available.with_a_bias_for(ActiveSupport::IsolatedExecutionState.context) do
            loop do
              synchronize do
                return if collected_conns.size == @connections.size && @now_connecting == 0
                remaining_timeout = timeout_time - Process.clock_gettime(Process::CLOCK_MONOTONIC)
                remaining_timeout = 0 if remaining_timeout < 0
                conn = checkout_for_exclusive_access(remaining_timeout)
                collected_conns   << conn
                newly_checked_out << conn
              end
            end
          end
        rescue ExclusiveConnectionTimeoutError
          # <tt>raise_on_acquisition_timeout == false</tt> means we are directed to ignore any
          # timeouts and are expected to just give up: we've obtained as many connections
          # as possible, note that in a case like that we don't return any of the
          # +newly_checked_out+ connections.

          if raise_on_acquisition_timeout
            release_newly_checked_out = true
            raise
          end
        rescue Exception # if something else went wrong
          # this can't be a "naked" rescue, because we have should return conns
          # even for non-StandardErrors
          release_newly_checked_out = true
          raise
        ensure
          if release_newly_checked_out && newly_checked_out
            # releasing only those conns that were checked out in this method, conns
            # checked outside this method (before it was called) are not for us to release
            newly_checked_out.each { |conn| checkin(conn) }
          end
        end

        #--
        # Must be called in a synchronize block.
        def checkout_for_exclusive_access(checkout_timeout)
          checkout(checkout_timeout)
        rescue ConnectionTimeoutError
          # this block can't be easily moved into attempt_to_checkout_all_existing_connections's
          # rescue block, because doing so would put it outside of synchronize section, without
          # being in a critical section thread_report might become inaccurate
          msg = +"could not obtain ownership of all database connections in #{checkout_timeout} seconds"

          thread_report = []
          @connections.each do |conn|
            unless conn.owner == ActiveSupport::IsolatedExecutionState.context
              thread_report << "#{conn} is owned by #{conn.owner}"
            end
          end

          msg << " (#{thread_report.join(', ')})" if thread_report.any?

          raise ExclusiveConnectionTimeoutError, msg
        end

        def with_new_connections_blocked
          synchronize do
            @threads_blocking_new_connections += 1
          end

          yield
        ensure
          num_new_conns_required = 0

          synchronize do
            @threads_blocking_new_connections -= 1

            if @threads_blocking_new_connections.zero?
              @available.clear

              num_new_conns_required = num_waiting_in_queue

              @connections.each do |conn|
                next if conn.in_use?

                @available.add conn
                num_new_conns_required -= 1
              end
            end
          end

          bulk_make_new_connections(num_new_conns_required) if num_new_conns_required > 0
        end

        # Acquire a connection by one of 1) immediately removing one
        # from the queue of available connections, 2) creating a new
        # connection if the pool is not at capacity, 3) waiting on the
        # queue for a connection to become available.
        #
        # Raises:
        # - ActiveRecord::ConnectionTimeoutError if a connection could not be acquired
        #
        #--
        # Implementation detail: the connection returned by +acquire_connection+
        # will already be "+connection.lease+ -ed" to the current thread.
        def acquire_connection(checkout_timeout)
          # NOTE: we rely on <tt>@available.poll</tt> and +try_to_checkout_new_connection+ to
          # +conn.lease+ the returned connection (and to do this in a +synchronized+
          # section). This is not the cleanest implementation, as ideally we would
          # <tt>synchronize { conn.lease }</tt> in this method, but by leaving it to <tt>@available.poll</tt>
          # and +try_to_checkout_new_connection+ we can piggyback on +synchronize+ sections
          # of the said methods and avoid an additional +synchronize+ overhead.
          if conn = @available.poll || try_to_checkout_new_connection
            conn
          else
            reap
            @available.poll(checkout_timeout)
          end
        end

        #--
        # if owner_thread param is omitted, this must be called in synchronize block
        def remove_connection_from_thread_cache(conn, owner_thread = conn.owner)
          @thread_cached_conns.delete_pair(connection_cache_key(owner_thread), conn)
        end
        alias_method :release, :remove_connection_from_thread_cache

        def new_connection
          Base.public_send(db_config.adapter_method, db_config.configuration_hash).tap do |conn|
            conn.check_version
          end
        end

        # If the pool is not at a <tt>@size</tt> limit, establish new connection. Connecting
        # to the DB is done outside main synchronized section.
        #--
        # Implementation constraint: a newly established connection returned by this
        # method must be in the +.leased+ state.
        def try_to_checkout_new_connection
          # first in synchronized section check if establishing new conns is allowed
          # and increment @now_connecting, to prevent overstepping this pool's @size
          # constraint
          do_checkout = synchronize do
            if @threads_blocking_new_connections.zero? && (@connections.size + @now_connecting) < @size
              @now_connecting += 1
            end
          end
          if do_checkout
            begin
              # if successfully incremented @now_connecting establish new connection
              # outside of synchronized section
              conn = checkout_new_connection
            ensure
              synchronize do
                if conn
                  adopt_connection(conn)
                  # returned conn needs to be already leased
                  conn.lease
                end
                @now_connecting -= 1
              end
            end
          end
        end

        def adopt_connection(conn)
          conn.pool = self
          @connections << conn
        end

        def checkout_new_connection
          raise ConnectionNotEstablished unless @automatic_reconnect
          new_connection
        end

        def checkout_and_verify(c)
          c._run_checkout_callbacks do
            c.verify!
          end
          c
        rescue
          remove c
          c.disconnect!
          raise
        end
    end
  end
end

connection_url_resolver.rb

# frozen_string_literal: true

require "uri"
require "active_support/core_ext/enumerable"
require "active_support/core_ext/hash/reverse_merge"

module ActiveRecord
  class DatabaseConfigurations
    # Expands a connection string into a hash.
    class ConnectionUrlResolver # :nodoc:
      # == Example
      #
      #   url = "postgresql://foo:bar@localhost:9000/foo_test?pool=5&timeout=3000"
      #   ConnectionUrlResolver.new(url).to_hash
      #   # => {
      #     adapter:  "postgresql",
      #     host:     "localhost",
      #     port:     9000,
      #     database: "foo_test",
      #     username: "foo",
      #     password: "bar",
      #     pool:     "5",
      #     timeout:  "3000"
      #   }
      def initialize(url)
        raise "Database URL cannot be empty" if url.blank?
        @uri     = uri_parser.parse(url)
        @adapter = @uri.scheme && @uri.scheme.tr("-", "_")
        @adapter = "postgresql" if @adapter == "postgres"

        if @uri.opaque
          @uri.opaque, @query = @uri.opaque.split("?", 2)
        else
          @query = @uri.query
        end
      end

      # Converts the given URL to a full connection hash.
      def to_hash
        config = raw_config.compact_blank
        config.map { |key, value| config[key] = uri_parser.unescape(value) if value.is_a? String }
        config
      end

      private
        attr_reader :uri

        def uri_parser
          @uri_parser ||= URI::Parser.new
        end

        # Converts the query parameters of the URI into a hash.
        #
        #   "localhost?pool=5&reaping_frequency=2"
        #   # => { pool: "5", reaping_frequency: "2" }
        #
        # returns empty hash if no query present.
        #
        #   "localhost"
        #   # => {}
        def query_hash
          Hash[(@query || "").split("&").map { |pair| pair.split("=", 2) }].symbolize_keys
        end

        def raw_config
          if uri.opaque
            query_hash.merge(
              adapter: @adapter,
              database: uri.opaque
            )
          else
            query_hash.reverse_merge(
              adapter: @adapter,
              username: uri.user,
              password: uri.password,
              port: uri.port,
              database: database_from_path,
              host: uri.hostname
            )
          end
        end

        # Returns name of the database.
        def database_from_path
          if @adapter == "sqlite3"
            # 'sqlite3:/foo' is absolute, because that makes sense. The
            # corresponding relative version, 'sqlite3:foo', is handled
            # elsewhere, as an "opaque".

            uri.path
          else
            # Only SQLite uses a filename as the "database" name; for
            # anything else, a leading slash would be silly.

            uri.path.delete_prefix("/")
          end
        end
    end
  end
end

console_sandbox.rb

# frozen_string_literal: true

ActiveRecord::ConnectionAdapters::AbstractAdapter.set_callback(:checkout, :after) do
  begin_transaction(joinable: false)
end

context.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # An encryption context configures the different entities used to perform encryption:
    #
    # * A key provider
    # * A key generator
    # * An encryptor, the facade to encrypt data
    # * A cipher, the encryption algorithm
    # * A message serializer
    class Context
      PROPERTIES = %i[ key_provider key_generator cipher message_serializer encryptor frozen_encryption ]

      attr_accessor(*PROPERTIES)

      def initialize
        set_defaults
      end

      alias frozen_encryption? frozen_encryption

      silence_redefinition_of_method :key_provider
      def key_provider
        @key_provider ||= build_default_key_provider
      end

      private
        def set_defaults
          self.frozen_encryption = false
          self.key_generator = ActiveRecord::Encryption::KeyGenerator.new
          self.cipher = ActiveRecord::Encryption::Cipher.new
          self.encryptor = ActiveRecord::Encryption::Encryptor.new
          self.message_serializer = ActiveRecord::Encryption::MessageSerializer.new
        end

        def build_default_key_provider
          ActiveRecord::Encryption::DerivedSecretKeyProvider.new(ActiveRecord::Encryption.config.primary_key)
        end
    end
  end
end

contexts.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # ActiveRecord::Encryption uses encryption contexts to configure the different entities used to
    # encrypt/decrypt at a given moment in time.
    #
    # By default, the library uses a default encryption context. This is the Context that gets configured
    # initially via +config.active_record.encryption+ options. Library users can define nested encryption contexts
    # when running blocks of code.
    #
    # See Context.
    module Contexts
      extend ActiveSupport::Concern

      included do
        mattr_reader :default_context, default: Context.new
        thread_mattr_accessor :custom_contexts
      end

      class_methods do
        # Configures a custom encryption context to use when running the provided block of code.
        #
        # It supports overriding all the properties defined in +Context+.
        #
        # Example:
        #
        #     ActiveRecord::Encryption.with_encryption_context(encryptor: ActiveRecord::Encryption::NullEncryptor.new) do
        #       ...
        #     end
        #
        # Encryption contexts can be nested.
        def with_encryption_context(properties)
          self.custom_contexts ||= []
          self.custom_contexts << default_context.dup
          properties.each do |key, value|
            self.current_custom_context.send("#{key}=", value)
          end

          yield
        ensure
          self.custom_contexts.pop
        end

        # Runs the provided block in an encryption context where encryption is disabled:
        #
        # * Reading encrypted content will return its ciphertexts.
        # * Writing encrypted content will write its clear text.
        def without_encryption(&block)
          with_encryption_context encryptor: ActiveRecord::Encryption::NullEncryptor.new, &block
        end

        # Runs the provided block in an encryption context where:
        #
        # * Reading encrypted content will return its ciphertext.
        # * Writing encrypted content will fail.
        def protecting_encrypted_data(&block)
          with_encryption_context encryptor: ActiveRecord::Encryption::EncryptingOnlyEncryptor.new, frozen_encryption: true, &block
        end

        # Returns the current context. By default it will return the current context.
        def context
          self.current_custom_context || self.default_context
        end

        def current_custom_context
          self.custom_contexts&.last
        end
      end
    end
  end
end

controller_runtime.rb

# frozen_string_literal: true

require "active_support/core_ext/module/attr_internal"
require "active_record/log_subscriber"

module ActiveRecord
  module Railties # :nodoc:
    module ControllerRuntime # :nodoc:
      extend ActiveSupport::Concern

      module ClassMethods # :nodoc:
        def log_process_action(payload)
          messages, db_runtime = super, payload[:db_runtime]
          messages << ("ActiveRecord: %.1fms" % db_runtime.to_f) if db_runtime
          messages
        end
      end

      private
        attr_internal :db_runtime

        def process_action(action, *args)
          # We also need to reset the runtime before each action
          # because of queries in middleware or in cases we are streaming
          # and it won't be cleaned up by the method below.
          ActiveRecord::LogSubscriber.reset_runtime
          super
        end

        def cleanup_view_runtime
          if logger && logger.info? && ActiveRecord::Base.connected?
            db_rt_before_render = ActiveRecord::LogSubscriber.reset_runtime
            self.db_runtime = (db_runtime || 0) + db_rt_before_render
            runtime = super
            db_rt_after_render = ActiveRecord::LogSubscriber.reset_runtime
            self.db_runtime += db_rt_after_render
            runtime - db_rt_after_render
          else
            super
          end
        end

        def append_info_to_payload(payload)
          super
          if ActiveRecord::Base.connected?
            payload[:db_runtime] = (db_runtime || 0) + ActiveRecord::LogSubscriber.reset_runtime
          end
        end
    end
  end
end

core.rb

# frozen_string_literal: true

require "active_support/core_ext/enumerable"
require "active_support/core_ext/string/filters"
require "active_support/parameter_filter"
require "concurrent/map"

module ActiveRecord
  module Core
    extend ActiveSupport::Concern
    include ActiveModel::Access

    included do
      ##
      # :singleton-method:
      #
      # Accepts a logger conforming to the interface of Log4r which is then
      # passed on to any new database connections made and which can be
      # retrieved on both a class and instance level by calling +logger+.
      class_attribute :logger, instance_writer: false

      ##
      # :singleton-method:
      #
      # Specifies the job used to destroy associations in the background
      class_attribute :destroy_association_async_job, instance_writer: false, instance_predicate: false, default: false

      ##
      # Contains the database configuration - as is typically stored in config/database.yml -
      # as an ActiveRecord::DatabaseConfigurations object.
      #
      # For example, the following database.yml...
      #
      #   development:
      #     adapter: sqlite3
      #     database: db/development.sqlite3
      #
      #   production:
      #     adapter: sqlite3
      #     database: db/production.sqlite3
      #
      # ...would result in ActiveRecord::Base.configurations to look like this:
      #
      #   #<ActiveRecord::DatabaseConfigurations:0x00007fd1acbdf800 @configurations=[
      #     #<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbded10 @env_name="development",
      #       @name="primary", @config={adapter: "sqlite3", database: "db/development.sqlite3"}>,
      #     #<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbdea90 @env_name="production",
      #       @name="primary", @config={adapter: "sqlite3", database: "db/production.sqlite3"}>
      #   ]>
      def self.configurations=(config)
        @@configurations = ActiveRecord::DatabaseConfigurations.new(config)
      end
      self.configurations = {}

      # Returns fully resolved ActiveRecord::DatabaseConfigurations object
      def self.configurations
        @@configurations
      end

      ##
      # :singleton-method:
      # Force enumeration of all columns in SELECT statements.
      # e.g. <tt>SELECT first_name, last_name FROM ...</tt> instead of <tt>SELECT * FROM ...</tt>
      # This avoids +PreparedStatementCacheExpired+ errors when a column is added
      # to the database while the app is running.
      class_attribute :enumerate_columns_in_select_statements, instance_accessor: false, default: false

      class_attribute :belongs_to_required_by_default, instance_accessor: false

      class_attribute :strict_loading_by_default, instance_accessor: false, default: false

      class_attribute :has_many_inversing, instance_accessor: false, default: false

      class_attribute :default_connection_handler, instance_writer: false

      class_attribute :default_role, instance_writer: false

      class_attribute :default_shard, instance_writer: false

      class_attribute :shard_selector, instance_accessor: false, default: nil

      def self.application_record_class? # :nodoc:
        if ActiveRecord.application_record_class
          self == ActiveRecord.application_record_class
        else
          if defined?(ApplicationRecord) && self == ApplicationRecord
            true
          end
        end
      end

      self.filter_attributes = []

      def self.connection_handler
        ActiveSupport::IsolatedExecutionState[:active_record_connection_handler] || default_connection_handler
      end

      def self.connection_handler=(handler)
        ActiveSupport::IsolatedExecutionState[:active_record_connection_handler] = handler
      end

      def self.connection_handlers
        if ActiveRecord.legacy_connection_handling
        else
          raise NotImplementedError, "The new connection handling does not support accessing multiple connection handlers."
        end

        @@connection_handlers ||= {}
      end

      def self.connection_handlers=(handlers)
        if ActiveRecord.legacy_connection_handling
          ActiveSupport::Deprecation.warn(<<~MSG)
            Using legacy connection handling is deprecated. Please set
            `legacy_connection_handling` to `false` in your application.

            The new connection handling does not support `connection_handlers`
            getter and setter.

            Read more about how to migrate at: https://guides.rubyonrails.org/active_record_multiple_databases.html#migrate-to-the-new-connection-handling
          MSG
        else
          raise NotImplementedError, "The new connection handling does not support multiple connection handlers."
        end

        @@connection_handlers = handlers
      end

      def self.asynchronous_queries_session # :nodoc:
        asynchronous_queries_tracker.current_session
      end

      def self.asynchronous_queries_tracker # :nodoc:
        ActiveSupport::IsolatedExecutionState[:active_record_asynchronous_queries_tracker] ||= \
          AsynchronousQueriesTracker.new
      end

      # Returns the symbol representing the current connected role.
      #
      #   ActiveRecord::Base.connected_to(role: :writing) do
      #     ActiveRecord::Base.current_role #=> :writing
      #   end
      #
      #   ActiveRecord::Base.connected_to(role: :reading) do
      #     ActiveRecord::Base.current_role #=> :reading
      #   end
      def self.current_role
        if ActiveRecord.legacy_connection_handling
          connection_handlers.key(connection_handler) || default_role
        else
          connected_to_stack.reverse_each do |hash|
            return hash[:role] if hash[:role] && hash[:klasses].include?(Base)
            return hash[:role] if hash[:role] && hash[:klasses].include?(connection_class_for_self)
          end

          default_role
        end
      end

      # Returns the symbol representing the current connected shard.
      #
      #   ActiveRecord::Base.connected_to(role: :reading) do
      #     ActiveRecord::Base.current_shard #=> :default
      #   end
      #
      #   ActiveRecord::Base.connected_to(role: :writing, shard: :one) do
      #     ActiveRecord::Base.current_shard #=> :one
      #   end
      def self.current_shard
        connected_to_stack.reverse_each do |hash|
          return hash[:shard] if hash[:shard] && hash[:klasses].include?(Base)
          return hash[:shard] if hash[:shard] && hash[:klasses].include?(connection_class_for_self)
        end

        default_shard
      end

      # Returns the symbol representing the current setting for
      # preventing writes.
      #
      #   ActiveRecord::Base.connected_to(role: :reading) do
      #     ActiveRecord::Base.current_preventing_writes #=> true
      #   end
      #
      #   ActiveRecord::Base.connected_to(role: :writing) do
      #     ActiveRecord::Base.current_preventing_writes #=> false
      #   end
      def self.current_preventing_writes
        if ActiveRecord.legacy_connection_handling
          connection_handler.prevent_writes
        else
          connected_to_stack.reverse_each do |hash|
            return hash[:prevent_writes] if !hash[:prevent_writes].nil? && hash[:klasses].include?(Base)
            return hash[:prevent_writes] if !hash[:prevent_writes].nil? && hash[:klasses].include?(connection_class_for_self)
          end

          false
        end
      end

      def self.connected_to_stack # :nodoc:
        if connected_to_stack = ActiveSupport::IsolatedExecutionState[:active_record_connected_to_stack]
          connected_to_stack
        else
          connected_to_stack = Concurrent::Array.new
          ActiveSupport::IsolatedExecutionState[:active_record_connected_to_stack] = connected_to_stack
          connected_to_stack
        end
      end

      def self.connection_class=(b) # :nodoc:
        @connection_class = b
      end

      def self.connection_class # :nodoc:
        @connection_class ||= false
      end

      def self.connection_class? # :nodoc:
        self.connection_class
      end

      def self.connection_class_for_self # :nodoc:
        klass = self

        until klass == Base
          break if klass.connection_class?
          klass = klass.superclass
        end

        klass
      end

      self.default_connection_handler = ConnectionAdapters::ConnectionHandler.new
      self.default_role = ActiveRecord.writing_role
      self.default_shard = :default

      def self.strict_loading_violation!(owner:, reflection:) # :nodoc:
        case ActiveRecord.action_on_strict_loading_violation
        when :raise
          message = "`#{owner}` is marked for strict_loading. The `#{reflection.klass}` association named `:#{reflection.name}` cannot be lazily loaded."
          raise ActiveRecord::StrictLoadingViolationError.new(message)
        when :log
          name = "strict_loading_violation.active_record"
          ActiveSupport::Notifications.instrument(name, owner: owner, reflection: reflection)
        end
      end
    end

    module ClassMethods
      def initialize_find_by_cache # :nodoc:
        @find_by_statement_cache = { true => Concurrent::Map.new, false => Concurrent::Map.new }
      end

      def inherited(child_class) # :nodoc:
        # initialize cache at class definition for thread safety
        child_class.initialize_find_by_cache
        unless child_class.base_class?
          klass = self
          until klass.base_class?
            klass.initialize_find_by_cache
            klass = klass.superclass
          end
        end
        super
      end

      def find(*ids) # :nodoc:
        # We don't have cache keys for this stuff yet
        return super unless ids.length == 1
        return super if block_given? || primary_key.nil? || scope_attributes?

        id = ids.first

        return super if StatementCache.unsupported_value?(id)

        cached_find_by([primary_key], [id]) ||
          raise(RecordNotFound.new("Couldn't find #{name} with '#{primary_key}'=#{id}", name, primary_key, id))
      end

      def find_by(*args) # :nodoc:
        return super if scope_attributes?

        hash = args.first
        return super unless Hash === hash

        hash = hash.each_with_object({}) do |(key, value), h|
          key = key.to_s
          key = attribute_aliases[key] || key

          return super if reflect_on_aggregation(key)

          reflection = _reflect_on_association(key)

          if !reflection
            value = value.id if value.respond_to?(:id)
          elsif reflection.belongs_to? && !reflection.polymorphic?
            key = reflection.join_foreign_key
            pkey = reflection.join_primary_key
            value = value.public_send(pkey) if value.respond_to?(pkey)
          end

          if !columns_hash.key?(key) || StatementCache.unsupported_value?(value)
            return super
          end

          h[key] = value
        end

        cached_find_by(hash.keys, hash.values)
      end

      def find_by!(*args) # :nodoc:
        find_by(*args) || where(*args).raise_record_not_found_exception!
      end

      %w(
        reading_role writing_role legacy_connection_handling default_timezone index_nested_attribute_errors
        verbose_query_logs queues warn_on_records_fetched_greater_than maintain_test_schema
        application_record_class action_on_strict_loading_violation schema_format error_on_ignored_order
        timestamped_migrations dump_schema_after_migration dump_schemas suppress_multiple_database_warning
      ).each do |attr|
        module_eval(<<~RUBY, __FILE__, __LINE__ + 1)
          def #{attr}
            ActiveSupport::Deprecation.warn(<<~MSG)
              ActiveRecord::Base.#{attr} is deprecated and will be removed in Rails 7.1.
              Use `ActiveRecord.#{attr}` instead.
            MSG
            ActiveRecord.#{attr}
          end

          def #{attr}=(value)
            ActiveSupport::Deprecation.warn(<<~MSG)
              ActiveRecord::Base.#{attr}= is deprecated and will be removed in Rails 7.1.
              Use `ActiveRecord.#{attr}=` instead.
            MSG
            ActiveRecord.#{attr} = value
          end
        RUBY
      end

      def initialize_generated_modules # :nodoc:
        generated_association_methods
      end

      def generated_association_methods # :nodoc:
        @generated_association_methods ||= begin
          mod = const_set(:GeneratedAssociationMethods, Module.new)
          private_constant :GeneratedAssociationMethods
          include mod

          mod
        end
      end

      # Returns columns which shouldn't be exposed while calling +#inspect+.
      def filter_attributes
        if defined?(@filter_attributes)
          @filter_attributes
        else
          superclass.filter_attributes
        end
      end

      # Specifies columns which shouldn't be exposed while calling +#inspect+.
      def filter_attributes=(filter_attributes)
        @inspection_filter = nil
        @filter_attributes = filter_attributes
      end

      def inspection_filter # :nodoc:
        if defined?(@filter_attributes)
          @inspection_filter ||= begin
            mask = InspectionMask.new(ActiveSupport::ParameterFilter::FILTERED)
            ActiveSupport::ParameterFilter.new(@filter_attributes, mask: mask)
          end
        else
          superclass.inspection_filter
        end
      end

      # Returns a string like 'Post(id:integer, title:string, body:text)'
      def inspect # :nodoc:
        if self == Base
          super
        elsif abstract_class?
          "#{super}(abstract)"
        elsif !connected?
          "#{super} (call '#{super}.connection' to establish a connection)"
        elsif table_exists?
          attr_list = attribute_types.map { |name, type| "#{name}: #{type.type}" } * ", "
          "#{super}(#{attr_list})"
        else
          "#{super}(Table doesn't exist)"
        end
      end

      # Override the default class equality method to provide support for decorated models.
      def ===(object) # :nodoc:
        object.is_a?(self)
      end

      # Returns an instance of <tt>Arel::Table</tt> loaded with the current table name.
      def arel_table # :nodoc:
        @arel_table ||= Arel::Table.new(table_name, klass: self)
      end

      def predicate_builder # :nodoc:
        @predicate_builder ||= PredicateBuilder.new(table_metadata)
      end

      def type_caster # :nodoc:
        TypeCaster::Map.new(self)
      end

      def cached_find_by_statement(key, &block) # :nodoc:
        cache = @find_by_statement_cache[connection.prepared_statements]
        cache.compute_if_absent(key) { StatementCache.create(connection, &block) }
      end

      private
        def relation
          relation = Relation.create(self)

          if finder_needs_type_condition? && !ignore_default_scope?
            relation.where!(type_condition)
          else
            relation
          end
        end

        def table_metadata
          TableMetadata.new(self, arel_table)
        end

        def cached_find_by(keys, values)
          statement = cached_find_by_statement(keys) { |params|
            wheres = keys.index_with { params.bind }
            where(wheres).limit(1)
          }

          begin
            statement.execute(values, connection).first
          rescue TypeError
            raise ActiveRecord::StatementInvalid
          end
        end
    end

    # New objects can be instantiated as either empty (pass no construction parameter) or pre-set with
    # attributes but not yet saved (pass a hash with key names matching the associated table column names).
    # In both instances, valid attribute keys are determined by the column names of the associated table --
    # hence you can't have attributes that aren't part of the table columns.
    #
    # ==== Example:
    #   # Instantiates a single new object
    #   User.new(first_name: 'Jamie')
    def initialize(attributes = nil)
      @new_record = true
      @attributes = self.class._default_attributes.deep_dup

      init_internals
      initialize_internals_callback

      assign_attributes(attributes) if attributes

      yield self if block_given?
      _run_initialize_callbacks
    end

    # Initialize an empty model object from +coder+. +coder+ should be
    # the result of previously encoding an Active Record model, using
    # #encode_with.
    #
    #   class Post < ActiveRecord::Base
    #   end
    #
    #   old_post = Post.new(title: "hello world")
    #   coder = {}
    #   old_post.encode_with(coder)
    #
    #   post = Post.allocate
    #   post.init_with(coder)
    #   post.title # => 'hello world'
    def init_with(coder, &block)
      coder = LegacyYamlAdapter.convert(coder)
      attributes = self.class.yaml_encoder.decode(coder)
      init_with_attributes(attributes, coder["new_record"], &block)
    end

    ##
    # Initialize an empty model object from +attributes+.
    # +attributes+ should be an attributes object, and unlike the
    # `initialize` method, no assignment calls are made per attribute.
    def init_with_attributes(attributes, new_record = false) # :nodoc:
      @new_record = new_record
      @attributes = attributes

      init_internals

      yield self if block_given?

      _run_find_callbacks
      _run_initialize_callbacks

      self
    end

    ##
    # :method: clone
    # Identical to Ruby's clone method.  This is a "shallow" copy.  Be warned that your attributes are not copied.
    # That means that modifying attributes of the clone will modify the original, since they will both point to the
    # same attributes hash. If you need a copy of your attributes hash, please use the #dup method.
    #
    #   user = User.first
    #   new_user = user.clone
    #   user.name               # => "Bob"
    #   new_user.name = "Joe"
    #   user.name               # => "Joe"
    #
    #   user.object_id == new_user.object_id            # => false
    #   user.name.object_id == new_user.name.object_id  # => true
    #
    #   user.name.object_id == user.dup.name.object_id  # => false

    ##
    # :method: dup
    # Duped objects have no id assigned and are treated as new records. Note
    # that this is a "shallow" copy as it copies the object's attributes
    # only, not its associations. The extent of a "deep" copy is application
    # specific and is therefore left to the application to implement according
    # to its need.
    # The dup method does not preserve the timestamps (created|updated)_(at|on).

    ##
    def initialize_dup(other) # :nodoc:
      @attributes = @attributes.deep_dup
      @attributes.reset(@primary_key)

      _run_initialize_callbacks

      @new_record               = true
      @previously_new_record    = false
      @destroyed                = false
      @_start_transaction_state = nil

      super
    end

    # Populate +coder+ with attributes about this record that should be
    # serialized. The structure of +coder+ defined in this method is
    # guaranteed to match the structure of +coder+ passed to the #init_with
    # method.
    #
    # Example:
    #
    #   class Post < ActiveRecord::Base
    #   end
    #   coder = {}
    #   Post.new.encode_with(coder)
    #   coder # => {"attributes" => {"id" => nil, ... }}
    def encode_with(coder)
      self.class.yaml_encoder.encode(@attributes, coder)
      coder["new_record"] = new_record?
      coder["active_record_yaml_version"] = 2
    end

    # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
    # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
    #
    # Note that new records are different from any other record by definition, unless the
    # other record is the receiver itself. Besides, if you fetch existing records with
    # +select+ and leave the ID out, you're on your own, this predicate will return false.
    #
    # Note also that destroying a record preserves its ID in the model instance, so deleted
    # models are still comparable.
    def ==(comparison_object)
      super ||
        comparison_object.instance_of?(self.class) &&
        !id.nil? &&
        comparison_object.id == id
    end
    alias :eql? :==

    # Delegates to id in order to allow two records of the same type and id to work with something like:
    #   [ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
    def hash
      id = self.id

      if id
        self.class.hash ^ id.hash
      else
        super
      end
    end

    # Clone and freeze the attributes hash such that associations are still
    # accessible, even on destroyed records, but cloned models will not be
    # frozen.
    def freeze
      @attributes = @attributes.clone.freeze
      self
    end

    # Returns +true+ if the attributes hash has been frozen.
    def frozen?
      @attributes.frozen?
    end

    # Allows sort on objects
    def <=>(other_object)
      if other_object.is_a?(self.class)
        to_key <=> other_object.to_key
      else
        super
      end
    end

    def present? # :nodoc:
      true
    end

    def blank? # :nodoc:
      false
    end

    # Returns +true+ if the record is read only.
    def readonly?
      @readonly
    end

    # Returns +true+ if the record is in strict_loading mode.
    def strict_loading?
      @strict_loading
    end

    # Sets the record to strict_loading mode. This will raise an error
    # if the record tries to lazily load an association.
    #
    #   user = User.first
    #   user.strict_loading! # => true
    #   user.comments
    #   => ActiveRecord::StrictLoadingViolationError
    #
    # === Parameters:
    #
    # * value - Boolean specifying whether to enable or disable strict loading.
    # * mode - Symbol specifying strict loading mode. Defaults to :all. Using
    #          :n_plus_one_only mode will only raise an error if an association
    #          that will lead to an n plus one query is lazily loaded.
    #
    # === Example:
    #
    #   user = User.first
    #   user.strict_loading!(false) # => false
    #   user.comments
    #   => #<ActiveRecord::Associations::CollectionProxy>
    def strict_loading!(value = true, mode: :all)
      unless [:all, :n_plus_one_only].include?(mode)
        raise ArgumentError, "The :mode option must be one of [:all, :n_plus_one_only] but #{mode.inspect} was provided."
      end

      @strict_loading_mode = mode
      @strict_loading = value
    end

    attr_reader :strict_loading_mode

    # Returns +true+ if the record uses strict_loading with +:n_plus_one_only+ mode enabled.
    def strict_loading_n_plus_one_only?
      @strict_loading_mode == :n_plus_one_only
    end

    # Marks this record as read only.
    def readonly!
      @readonly = true
    end

    def connection_handler
      self.class.connection_handler
    end

    # Returns the contents of the record as a nicely formatted string.
    def inspect
      # We check defined?(@attributes) not to issue warnings if the object is
      # allocated but not initialized.
      inspection = if defined?(@attributes) && @attributes
        self.class.attribute_names.filter_map do |name|
          if _has_attribute?(name)
            "#{name}: #{attribute_for_inspect(name)}"
          end
        end.join(", ")
      else
        "not initialized"
      end

      "#<#{self.class} #{inspection}>"
    end

    # Takes a PP and prettily prints this record to it, allowing you to get a nice result from <tt>pp record</tt>
    # when pp is required.
    def pretty_print(pp)
      return super if custom_inspect_method_defined?
      pp.object_address_group(self) do
        if defined?(@attributes) && @attributes
          attr_names = self.class.attribute_names.select { |name| _has_attribute?(name) }
          pp.seplist(attr_names, proc { pp.text "," }) do |attr_name|
            pp.breakable " "
            pp.group(1) do
              pp.text attr_name
              pp.text ":"
              pp.breakable
              value = _read_attribute(attr_name)
              value = inspection_filter.filter_param(attr_name, value) unless value.nil?
              pp.pp value
            end
          end
        else
          pp.breakable " "
          pp.text "not initialized"
        end
      end
    end

    ##
    # :method: slice
    #
    # :call-seq: slice(*methods)
    #
    # Returns a hash of the given methods with their names as keys and returned
    # values as values.
    #
    #--
    # Implemented by ActiveModel::Access#slice.

    ##
    # :method: values_at
    #
    # :call-seq: values_at(*methods)
    #
    # Returns an array of the values returned by the given methods.
    #
    #--
    # Implemented by ActiveModel::Access#values_at.

    private
      # +Array#flatten+ will call +#to_ary+ (recursively) on each of the elements of
      # the array, and then rescues from the possible +NoMethodError+. If those elements are
      # +ActiveRecord::Base+'s, then this triggers the various +method_missing+'s that we have,
      # which significantly impacts upon performance.
      #
      # So we can avoid the +method_missing+ hit by explicitly defining +#to_ary+ as +nil+ here.
      #
      # See also https://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary.html
      def to_ary
        nil
      end

      def init_internals
        @readonly                 = false
        @previously_new_record    = false
        @destroyed                = false
        @marked_for_destruction   = false
        @destroyed_by_association = nil
        @_start_transaction_state = nil

        klass = self.class

        @primary_key         = klass.primary_key
        @strict_loading      = klass.strict_loading_by_default
        @strict_loading_mode = :all

        klass.define_attribute_methods
      end

      def initialize_internals_callback
      end

      def custom_inspect_method_defined?
        self.class.instance_method(:inspect).owner != ActiveRecord::Base.instance_method(:inspect).owner
      end

      class InspectionMask < DelegateClass(::String)
        def pretty_print(pp)
          pp.text __getobj__
        end
      end
      private_constant :InspectionMask

      def inspection_filter
        self.class.inspection_filter
      end
  end
end

count.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Count < Arel::Nodes::Function
      def initialize(expr, distinct = false, aliaz = nil)
        super(expr, aliaz)
        @distinct = distinct
      end
    end
  end
end

counter_cache.rb

# frozen_string_literal: true

module ActiveRecord
  # = Active Record Counter Cache
  module CounterCache
    extend ActiveSupport::Concern

    module ClassMethods
      # Resets one or more counter caches to their correct value using an SQL
      # count query. This is useful when adding new counter caches, or if the
      # counter has been corrupted or modified directly by SQL.
      #
      # ==== Parameters
      #
      # * +id+ - The id of the object you wish to reset a counter on.
      # * +counters+ - One or more association counters to reset. Association name or counter name can be given.
      # * <tt>:touch</tt> - Touch timestamp columns when updating.
      #   Pass +true+ to touch +updated_at+ and/or +updated_on+. Pass a symbol to
      #   touch that column or an array of symbols to touch just those ones.
      #
      # ==== Examples
      #
      #   # For the Post with id #1, reset the comments_count
      #   Post.reset_counters(1, :comments)
      #
      #   # Like above, but also touch the +updated_at+ and/or +updated_on+
      #   # attributes.
      #   Post.reset_counters(1, :comments, touch: true)
      def reset_counters(id, *counters, touch: nil)
        object = find(id)

        counters.each do |counter_association|
          has_many_association = _reflect_on_association(counter_association)
          unless has_many_association
            has_many = reflect_on_all_associations(:has_many)
            has_many_association = has_many.find { |association| association.counter_cache_column && association.counter_cache_column.to_sym == counter_association.to_sym }
            counter_association = has_many_association.plural_name if has_many_association
          end
          raise ArgumentError, "'#{name}' has no association called '#{counter_association}'" unless has_many_association

          if has_many_association.is_a? ActiveRecord::Reflection::ThroughReflection
            has_many_association = has_many_association.through_reflection
          end

          foreign_key  = has_many_association.foreign_key.to_s
          child_class  = has_many_association.klass
          reflection   = child_class._reflections.values.find { |e| e.belongs_to? && e.foreign_key.to_s == foreign_key && e.options[:counter_cache].present? }
          counter_name = reflection.counter_cache_column

          updates = { counter_name => object.send(counter_association).count(:all) }

          if touch
            names = touch if touch != true
            names = Array.wrap(names)
            options = names.extract_options!
            touch_updates = touch_attributes_with_time(*names, **options)
            updates.merge!(touch_updates)
          end

          unscoped.where(primary_key => object.id).update_all(updates)
        end

        true
      end

      # A generic "counter updater" implementation, intended primarily to be
      # used by #increment_counter and #decrement_counter, but which may also
      # be useful on its own. It simply does a direct SQL update for the record
      # with the given ID, altering the given hash of counters by the amount
      # given by the corresponding value:
      #
      # ==== Parameters
      #
      # * +id+ - The id of the object you wish to update a counter on or an array of ids.
      # * +counters+ - A Hash containing the names of the fields
      #   to update as keys and the amount to update the field by as values.
      # * <tt>:touch</tt> option - Touch timestamp columns when updating.
      #   If attribute names are passed, they are updated along with updated_at/on
      #   attributes.
      #
      # ==== Examples
      #
      #   # For the Post with id of 5, decrement the comment_count by 1, and
      #   # increment the action_count by 1
      #   Post.update_counters 5, comment_count: -1, action_count: 1
      #   # Executes the following SQL:
      #   # UPDATE posts
      #   #    SET comment_count = COALESCE(comment_count, 0) - 1,
      #   #        action_count = COALESCE(action_count, 0) + 1
      #   #  WHERE id = 5
      #
      #   # For the Posts with id of 10 and 15, increment the comment_count by 1
      #   Post.update_counters [10, 15], comment_count: 1
      #   # Executes the following SQL:
      #   # UPDATE posts
      #   #    SET comment_count = COALESCE(comment_count, 0) + 1
      #   #  WHERE id IN (10, 15)
      #
      #   # For the Posts with id of 10 and 15, increment the comment_count by 1
      #   # and update the updated_at value for each counter.
      #   Post.update_counters [10, 15], comment_count: 1, touch: true
      #   # Executes the following SQL:
      #   # UPDATE posts
      #   #    SET comment_count = COALESCE(comment_count, 0) + 1,
      #   #    `updated_at` = '2016-10-13T09:59:23-05:00'
      #   #  WHERE id IN (10, 15)
      def update_counters(id, counters)
        unscoped.where!(primary_key => id).update_counters(counters)
      end

      # Increment a numeric field by one, via a direct SQL update.
      #
      # This method is used primarily for maintaining counter_cache columns that are
      # used to store aggregate values. For example, a +DiscussionBoard+ may cache
      # posts_count and comments_count to avoid running an SQL query to calculate the
      # number of posts and comments there are, each time it is displayed.
      #
      # ==== Parameters
      #
      # * +counter_name+ - The name of the field that should be incremented.
      # * +id+ - The id of the object that should be incremented or an array of ids.
      # * <tt>:touch</tt> - Touch timestamp columns when updating.
      #   Pass +true+ to touch +updated_at+ and/or +updated_on+. Pass a symbol to
      #   touch that column or an array of symbols to touch just those ones.
      #
      # ==== Examples
      #
      #   # Increment the posts_count column for the record with an id of 5
      #   DiscussionBoard.increment_counter(:posts_count, 5)
      #
      #   # Increment the posts_count column for the record with an id of 5
      #   # and update the updated_at value.
      #   DiscussionBoard.increment_counter(:posts_count, 5, touch: true)
      def increment_counter(counter_name, id, touch: nil)
        update_counters(id, counter_name => 1, touch: touch)
      end

      # Decrement a numeric field by one, via a direct SQL update.
      #
      # This works the same as #increment_counter but reduces the column value by
      # 1 instead of increasing it.
      #
      # ==== Parameters
      #
      # * +counter_name+ - The name of the field that should be decremented.
      # * +id+ - The id of the object that should be decremented or an array of ids.
      # * <tt>:touch</tt> - Touch timestamp columns when updating.
      #   Pass +true+ to touch +updated_at+ and/or +updated_on+. Pass a symbol to
      #   touch that column or an array of symbols to touch just those ones.
      #
      # ==== Examples
      #
      #   # Decrement the posts_count column for the record with an id of 5
      #   DiscussionBoard.decrement_counter(:posts_count, 5)
      #
      #   # Decrement the posts_count column for the record with an id of 5
      #   # and update the updated_at value.
      #   DiscussionBoard.decrement_counter(:posts_count, 5, touch: true)
      def decrement_counter(counter_name, id, touch: nil)
        update_counters(id, counter_name => -1, touch: touch)
      end
    end

    private
      def _create_record(attribute_names = self.attribute_names)
        id = super

        each_counter_cached_associations do |association|
          association.increment_counters
        end

        id
      end

      def destroy_row
        affected_rows = super

        if affected_rows > 0
          each_counter_cached_associations do |association|
            foreign_key = association.reflection.foreign_key.to_sym
            unless destroyed_by_association && destroyed_by_association.foreign_key.to_sym == foreign_key
              association.decrement_counters
            end
          end
        end

        affected_rows
      end

      def each_counter_cached_associations
        _reflections.each do |name, reflection|
          yield association(name.to_sym) if reflection.belongs_to? && reflection.counter_cache_column
        end
      end
  end
end

crud.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  ###
  # FIXME hopefully we can remove this
  module Crud
    def compile_insert(values)
      im = create_insert
      im.insert values
      im
    end

    def create_insert
      InsertManager.new
    end

    def compile_update(
      values,
      key = nil,
      having_clause = nil,
      group_values_columns = []
    )
      um = UpdateManager.new(source)
      um.set(values)
      um.take(limit)
      um.offset(offset)
      um.order(*orders)
      um.wheres = constraints
      um.key = key

      um.group(group_values_columns) unless group_values_columns.empty?
      um.having(having_clause) unless having_clause.nil?
      um
    end

    def compile_delete(key = nil, having_clause = nil, group_values_columns = [])
      dm = DeleteManager.new(source)
      dm.take(limit)
      dm.offset(offset)
      dm.order(*orders)
      dm.wheres = constraints
      dm.key = key
      dm.group(group_values_columns) unless group_values_columns.empty?
      dm.having(having_clause) unless having_clause.nil?
      dm
    end
  end
end

database_config.rb

# frozen_string_literal: true

module ActiveRecord
  class DatabaseConfigurations
    # ActiveRecord::Base.configurations will return either a HashConfig or
    # UrlConfig respectively. It will never return a DatabaseConfig object,
    # as this is the parent class for the types of database configuration objects.
    class DatabaseConfig # :nodoc:
      attr_reader :env_name, :name

      attr_accessor :owner_name

      def initialize(env_name, name)
        @env_name = env_name
        @name = name
      end

      def adapter_method
        "#{adapter}_connection"
      end

      def host
        raise NotImplementedError
      end

      def database
        raise NotImplementedError
      end

      def _database=(database)
        raise NotImplementedError
      end

      def adapter
        raise NotImplementedError
      end

      def pool
        raise NotImplementedError
      end

      def min_threads
        raise NotImplementedError
      end

      def max_threads
        raise NotImplementedError
      end

      def max_queue
        raise NotImplementedError
      end

      def checkout_timeout
        raise NotImplementedError
      end

      def reaping_frequency
        raise NotImplementedError
      end

      def idle_timeout
        raise NotImplementedError
      end

      def replica?
        raise NotImplementedError
      end

      def migrations_paths
        raise NotImplementedError
      end

      def for_current_env?
        env_name == ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
      end

      def schema_cache_path
        raise NotImplementedError
      end
    end
  end
end

database_configurations.rb

# frozen_string_literal: true

require "uri"
require "active_record/database_configurations/database_config"
require "active_record/database_configurations/hash_config"
require "active_record/database_configurations/url_config"
require "active_record/database_configurations/connection_url_resolver"

module ActiveRecord
  # ActiveRecord::DatabaseConfigurations returns an array of DatabaseConfig
  # objects (either a HashConfig or UrlConfig) that are constructed from the
  # application's database configuration hash or URL string.
  class DatabaseConfigurations
    class InvalidConfigurationError < StandardError; end

    attr_reader :configurations
    delegate :any?, to: :configurations

    def initialize(configurations = {})
      @configurations = build_configs(configurations)
    end

    # Collects the configs for the environment and optionally the specification
    # name passed in. To include replica configurations pass <tt>include_hidden: true</tt>.
    #
    # If a name is provided a single DatabaseConfig object will be
    # returned, otherwise an array of DatabaseConfig objects will be
    # returned that corresponds with the environment and type requested.
    #
    # ==== Options
    #
    # * <tt>env_name:</tt> The environment name. Defaults to +nil+ which will collect
    #   configs for all environments.
    # * <tt>name:</tt> The db config name (i.e. primary, animals, etc.). Defaults
    #   to +nil+. If no +env_name+ is specified the config for the default env and the
    #   passed +name+ will be returned.
    # * <tt>include_replicas:</tt> Deprecated. Determines whether to include replicas in
    #   the returned list. Most of the time we're only iterating over the write
    #   connection (i.e. migrations don't need to run for the write and read connection).
    #   Defaults to +false+.
    # * <tt>include_hidden:</tt> Determines whether to include replicas and configurations
    #   hidden by +database_tasks: false+ in the returned list. Most of the time we're only
    #   iterating over the primary connections (i.e. migrations don't need to run for the
    #   write and read connection). Defaults to +false+.
    def configs_for(env_name: nil, name: nil, include_replicas: false, include_hidden: false)
      if include_replicas
        include_hidden = include_replicas
        ActiveSupport::Deprecation.warn("The kwarg `include_replicas` is deprecated in favor of `include_hidden`. When `include_hidden` is passed, configurations with `replica: true` or `database_tasks: false` will be returned. `include_replicas` will be removed in Rails 7.1.")
      end

      env_name ||= default_env if name
      configs = env_with_configs(env_name)

      unless include_hidden
        configs = configs.select do |db_config|
          db_config.database_tasks?
        end
      end

      if name
        configs.find do |db_config|
          db_config.name == name
        end
      else
        configs
      end
    end

    # Returns a single DatabaseConfig object based on the requested environment.
    #
    # If the application has multiple databases +find_db_config+ will return
    # the first DatabaseConfig for the environment.
    def find_db_config(env)
      configurations
        .sort_by.with_index { |db_config, i| db_config.for_current_env? ? [0, i] : [1, i] }
        .find do |db_config|
          db_config.env_name == env.to_s ||
            (db_config.for_current_env? && db_config.name == env.to_s)
        end
    end

    # A primary configuration is one that is named primary or if there is
    # no primary, the first configuration for an environment will be treated
    # as primary. This is used as the "default" configuration and is used
    # when the application needs to treat one configuration differently. For
    # example, when Rails dumps the schema, the primary configuration's schema
    # file will be named `schema.rb` instead of `primary_schema.rb`.
    def primary?(name) # :nodoc:
      return true if name == "primary"

      first_config = find_db_config(default_env)
      first_config && name == first_config.name
    end

    # Checks if the application's configurations are empty.
    #
    # Aliased to blank?
    def empty?
      configurations.empty?
    end
    alias :blank? :empty?

    # Returns fully resolved connection, accepts hash, string or symbol.
    # Always returns a DatabaseConfiguration::DatabaseConfig
    #
    # == Examples
    #
    # Symbol representing current environment.
    #
    #   DatabaseConfigurations.new("production" => {}).resolve(:production)
    #   # => DatabaseConfigurations::HashConfig.new(env_name: "production", config: {})
    #
    # One layer deep hash of connection values.
    #
    #   DatabaseConfigurations.new({}).resolve("adapter" => "sqlite3")
    #   # => DatabaseConfigurations::HashConfig.new(config: {"adapter" => "sqlite3"})
    #
    # Connection URL.
    #
    #   DatabaseConfigurations.new({}).resolve("postgresql://localhost/foo")
    #   # => DatabaseConfigurations::UrlConfig.new(config: {"adapter" => "postgresql", "host" => "localhost", "database" => "foo"})
    def resolve(config) # :nodoc:
      return config if DatabaseConfigurations::DatabaseConfig === config

      case config
      when Symbol
        resolve_symbol_connection(config)
      when Hash, String
        build_db_config_from_raw_config(default_env, "primary", config)
      else
        raise TypeError, "Invalid type for configuration. Expected Symbol, String, or Hash. Got #{config.inspect}"
      end
    end

    private
      def default_env
        ActiveRecord::ConnectionHandling::DEFAULT_ENV.call.to_s
      end

      def env_with_configs(env = nil)
        if env
          configurations.select { |db_config| db_config.env_name == env }
        else
          configurations
        end
      end

      def build_configs(configs)
        return configs.configurations if configs.is_a?(DatabaseConfigurations)
        return configs if configs.is_a?(Array)

        db_configs = configs.flat_map do |env_name, config|
          if config.is_a?(Hash) && config.values.all?(Hash)
            walk_configs(env_name.to_s, config)
          else
            build_db_config_from_raw_config(env_name.to_s, "primary", config)
          end
        end

        unless db_configs.find(&:for_current_env?)
          db_configs << environment_url_config(default_env, "primary", {})
        end

        merge_db_environment_variables(default_env, db_configs.compact)
      end

      def walk_configs(env_name, config)
        config.map do |name, sub_config|
          build_db_config_from_raw_config(env_name, name.to_s, sub_config)
        end
      end

      def resolve_symbol_connection(name)
        if db_config = find_db_config(name)
          db_config
        else
          raise AdapterNotSpecified, <<~MSG
            The `#{name}` database is not configured for the `#{default_env}` environment.

              Available database configurations are:

              #{build_configuration_sentence}
          MSG
        end
      end

      def build_configuration_sentence
        configs = configs_for(include_hidden: true)

        configs.group_by(&:env_name).map do |env, config|
          names = config.map(&:name)
          if names.size > 1
            "#{env}: #{names.join(", ")}"
          else
            env
          end
        end.join("\n")
      end

      def build_db_config_from_raw_config(env_name, name, config)
        case config
        when String
          build_db_config_from_string(env_name, name, config)
        when Hash
          build_db_config_from_hash(env_name, name, config.symbolize_keys)
        else
          raise InvalidConfigurationError, "'{ #{env_name} => #{config} }' is not a valid configuration. Expected '#{config}' to be a URL string or a Hash."
        end
      end

      def build_db_config_from_string(env_name, name, config)
        url = config
        uri = URI.parse(url)
        if uri.scheme
          UrlConfig.new(env_name, name, url)
        else
          raise InvalidConfigurationError, "'{ #{env_name} => #{config} }' is not a valid configuration. Expected '#{config}' to be a URL string or a Hash."
        end
      end

      def build_db_config_from_hash(env_name, name, config)
        if config.has_key?(:url)
          url = config[:url]
          config_without_url = config.dup
          config_without_url.delete :url

          UrlConfig.new(env_name, name, url, config_without_url)
        else
          HashConfig.new(env_name, name, config)
        end
      end

      def merge_db_environment_variables(current_env, configs)
        configs.map do |config|
          next config if config.is_a?(UrlConfig) || config.env_name != current_env

          url_config = environment_url_config(current_env, config.name, config.configuration_hash)
          url_config || config
        end
      end

      def environment_url_config(env, name, config)
        url = environment_value_for(name)
        return unless url

        UrlConfig.new(env, name, url, config)
      end

      def environment_value_for(name)
        name_env_key = "#{name.upcase}_DATABASE_URL"
        url = ENV[name_env_key]
        url ||= ENV["DATABASE_URL"] if name == "primary"
        url
      end
  end
end

database_limits.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters # :nodoc:
    module DatabaseLimits
      def max_identifier_length # :nodoc:
        64
      end

      # Returns the maximum length of a table alias.
      def table_alias_length
        max_identifier_length
      end

      # Returns the maximum length of an index name.
      def index_name_length
        max_identifier_length
      end

      private
        def bind_params_length
          65535
        end
    end
  end
end

database_selector.rb

# frozen_string_literal: true

require "active_record/middleware/database_selector/resolver"

module ActiveRecord
  module Middleware
    # The DatabaseSelector Middleware provides a framework for automatically
    # swapping from the primary to the replica database connection. Rails
    # provides a basic framework to determine when to swap and allows for
    # applications to write custom strategy classes to override the default
    # behavior.
    #
    # The resolver class defines when the application should switch (i.e. read
    # from the primary if a write occurred less than 2 seconds ago) and a
    # resolver context class that sets a value that helps the resolver class
    # decide when to switch.
    #
    # Rails default middleware uses the request's session to set a timestamp
    # that informs the application when to read from a primary or read from a
    # replica.
    #
    # To use the DatabaseSelector in your application with default settings add
    # the following options to your environment config:
    #
    #   # This require is only necessary when using `rails new app --minimal`
    #   require "active_support/core_ext/integer/time"
    #
    #   class Application < Rails::Application
    #     config.active_record.database_selector = { delay: 2.seconds }
    #     config.active_record.database_resolver = ActiveRecord::Middleware::DatabaseSelector::Resolver
    #     config.active_record.database_resolver_context = ActiveRecord::Middleware::DatabaseSelector::Resolver::Session
    #   end
    #
    # New applications will include these lines commented out in the production.rb.
    #
    # The default behavior can be changed by setting the config options to a
    # custom class:
    #
    #   config.active_record.database_selector = { delay: 2.seconds }
    #   config.active_record.database_resolver = MyResolver
    #   config.active_record.database_resolver_context = MyResolver::MySession
    class DatabaseSelector
      def initialize(app, resolver_klass = nil, context_klass = nil, options = {})
        @app = app
        @resolver_klass = resolver_klass || Resolver
        @context_klass = context_klass || Resolver::Session
        @options = options
      end

      attr_reader :resolver_klass, :context_klass, :options

      # Middleware that determines which database connection to use in a multiple
      # database application.
      def call(env)
        request = ActionDispatch::Request.new(env)

        select_database(request) do
          @app.call(env)
        end
      end

      private
        def select_database(request, &blk)
          context = context_klass.call(request)
          resolver = resolver_klass.call(context, options)

          response = if reading_request?(request)
            resolver.read(&blk)
          else
            resolver.write(&blk)
          end

          resolver.update_context(response)
          response
        end

        def reading_request?(request)
          request.get? || request.head?
        end
    end
  end
end

database_statements.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module SQLite3
      module DatabaseStatements
        READ_QUERY = ActiveRecord::ConnectionAdapters::AbstractAdapter.build_read_query_regexp(
          :pragma
        ) # :nodoc:
        private_constant :READ_QUERY

        def write_query?(sql) # :nodoc:
          !READ_QUERY.match?(sql)
        rescue ArgumentError # Invalid encoding
          !READ_QUERY.match?(sql.b)
        end

        def explain(arel, binds = [])
          sql = "EXPLAIN QUERY PLAN #{to_sql(arel, binds)}"
          SQLite3::ExplainPrettyPrinter.new.pp(exec_query(sql, "EXPLAIN", []))
        end

        def execute(sql, name = nil) # :nodoc:
          sql = transform_query(sql)
          check_if_write_query(sql)

          materialize_transactions
          mark_transaction_written_if_write(sql)

          log(sql, name) do
            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
              @raw_connection.execute(sql)
            end
          end
        end

        def exec_query(sql, name = nil, binds = [], prepare: false, async: false) # :nodoc:
          sql = transform_query(sql)
          check_if_write_query(sql)

          materialize_transactions
          mark_transaction_written_if_write(sql)

          type_casted_binds = type_casted_binds(binds)

          log(sql, name, binds, type_casted_binds, async: async) do
            ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
              # Don't cache statements if they are not prepared
              unless prepare
                stmt = @raw_connection.prepare(sql)
                begin
                  cols = stmt.columns
                  unless without_prepared_statement?(binds)
                    stmt.bind_params(type_casted_binds)
                  end
                  records = stmt.to_a
                ensure
                  stmt.close
                end
              else
                stmt = @statements[sql] ||= @raw_connection.prepare(sql)
                cols = stmt.columns
                stmt.reset!
                stmt.bind_params(type_casted_binds)
                records = stmt.to_a
              end

              build_result(columns: cols, rows: records)
            end
          end
        end

        def exec_delete(sql, name = "SQL", binds = []) # :nodoc:
          exec_query(sql, name, binds)
          @raw_connection.changes
        end
        alias :exec_update :exec_delete

        def begin_isolated_db_transaction(isolation) # :nodoc:
          raise TransactionIsolationError, "SQLite3 only supports the `read_uncommitted` transaction isolation level" if isolation != :read_uncommitted
          raise StandardError, "You need to enable the shared-cache mode in SQLite mode before attempting to change the transaction isolation level" unless shared_cache?

          ActiveSupport::IsolatedExecutionState[:active_record_read_uncommitted] = @raw_connection.get_first_value("PRAGMA read_uncommitted")
          @raw_connection.read_uncommitted = true
          begin_db_transaction
        end

        def begin_db_transaction # :nodoc:
          log("begin transaction", "TRANSACTION") { @raw_connection.transaction }
        end

        def commit_db_transaction # :nodoc:
          log("commit transaction", "TRANSACTION") { @raw_connection.commit }
          reset_read_uncommitted
        end

        def exec_rollback_db_transaction # :nodoc:
          log("rollback transaction", "TRANSACTION") { @raw_connection.rollback }
          reset_read_uncommitted
        end

        # https://stackoverflow.com/questions/17574784
        # https://www.sqlite.org/lang_datefunc.html
        HIGH_PRECISION_CURRENT_TIMESTAMP = Arel.sql("STRFTIME('%Y-%m-%d %H:%M:%f', 'NOW')").freeze # :nodoc:
        private_constant :HIGH_PRECISION_CURRENT_TIMESTAMP

        def high_precision_current_timestamp
          HIGH_PRECISION_CURRENT_TIMESTAMP
        end

        private
          def reset_read_uncommitted
            read_uncommitted = ActiveSupport::IsolatedExecutionState[:active_record_read_uncommitted]
            return unless read_uncommitted

            @raw_connection.read_uncommitted = read_uncommitted
          end

          def execute_batch(statements, name = nil)
            statements = statements.map { |sql| transform_query(sql) }
            sql = combine_multi_statements(statements)

            check_if_write_query(sql)

            materialize_transactions
            mark_transaction_written_if_write(sql)

            log(sql, name) do
              ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
                @raw_connection.execute_batch2(sql)
              end
            end
          end

          def last_inserted_id(result)
            @raw_connection.last_insert_row_id
          end

          def build_fixture_statements(fixture_set)
            fixture_set.flat_map do |table_name, fixtures|
              next if fixtures.empty?
              fixtures.map { |fixture| build_fixture_sql([fixture], table_name) }
            end.compact
          end

          def build_truncate_statement(table_name)
            "DELETE FROM #{quote_table_name(table_name)}"
          end
      end
    end
  end
end

database_tasks.rb

# frozen_string_literal: true

require "active_record/database_configurations"

module ActiveRecord
  module Tasks # :nodoc:
    class DatabaseNotSupported < StandardError; end # :nodoc:

    # ActiveRecord::Tasks::DatabaseTasks is a utility class, which encapsulates
    # logic behind common tasks used to manage database and migrations.
    #
    # The tasks defined here are used with Rails commands provided by Active Record.
    #
    # In order to use DatabaseTasks, a few config values need to be set. All the needed
    # config values are set by Rails already, so it's necessary to do it only if you
    # want to change the defaults or when you want to use Active Record outside of Rails
    # (in such case after configuring the database tasks, you can also use the rake tasks
    # defined in Active Record).
    #
    # The possible config values are:
    #
    # * +env+: current environment (like Rails.env).
    # * +database_configuration+: configuration of your databases (as in +config/database.yml+).
    # * +db_dir+: your +db+ directory.
    # * +fixtures_path+: a path to fixtures directory.
    # * +migrations_paths+: a list of paths to directories with migrations.
    # * +seed_loader+: an object which will load seeds, it needs to respond to the +load_seed+ method.
    # * +root+: a path to the root of the application.
    #
    # Example usage of DatabaseTasks outside Rails could look as such:
    #
    #   include ActiveRecord::Tasks
    #   DatabaseTasks.database_configuration = YAML.load_file('my_database_config.yml')
    #   DatabaseTasks.db_dir = 'db'
    #   # other settings...
    #
    #   DatabaseTasks.create_current('production')
    module DatabaseTasks
      ##
      # :singleton-method:
      # Extra flags passed to database CLI tool (mysqldump/pg_dump) when calling db:schema:dump
      # It can be used as a string/array (the typical case) or a hash (when you use multiple adapters)
      # Example:
      #   ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags = {
      #     mysql2: ['--no-defaults', '--skip-add-drop-table'],
      #     postgres: '--no-tablespaces'
      #   }
      mattr_accessor :structure_dump_flags, instance_accessor: false

      ##
      # :singleton-method:
      # Extra flags passed to database CLI tool when calling db:schema:load
      # It can be used as a string/array (the typical case) or a hash (when you use multiple adapters)
      mattr_accessor :structure_load_flags, instance_accessor: false

      extend self

      attr_writer :db_dir, :migrations_paths, :fixtures_path, :root, :env, :seed_loader
      attr_accessor :database_configuration

      LOCAL_HOSTS = ["127.0.0.1", "localhost"]

      def check_protected_environments!
        unless ENV["DISABLE_DATABASE_ENVIRONMENT_CHECK"]
          current = ActiveRecord::Base.connection.migration_context.current_environment
          stored  = ActiveRecord::Base.connection.migration_context.last_stored_environment

          if ActiveRecord::Base.connection.migration_context.protected_environment?
            raise ActiveRecord::ProtectedEnvironmentError.new(stored)
          end

          if stored && stored != current
            raise ActiveRecord::EnvironmentMismatchError.new(current: current, stored: stored)
          end
        end
      rescue ActiveRecord::NoDatabaseError
      end

      def register_task(pattern, task)
        @tasks ||= {}
        @tasks[pattern] = task
      end

      register_task(/mysql/,        "ActiveRecord::Tasks::MySQLDatabaseTasks")
      register_task(/postgresql/,   "ActiveRecord::Tasks::PostgreSQLDatabaseTasks")
      register_task(/sqlite/,       "ActiveRecord::Tasks::SQLiteDatabaseTasks")

      def db_dir
        @db_dir ||= Rails.application.config.paths["db"].first
      end

      def migrations_paths
        @migrations_paths ||= Rails.application.paths["db/migrate"].to_a
      end

      def fixtures_path
        @fixtures_path ||= if ENV["FIXTURES_PATH"]
          File.join(root, ENV["FIXTURES_PATH"])
        else
          File.join(root, "test", "fixtures")
        end
      end

      def root
        @root ||= Rails.root
      end

      def env
        @env ||= Rails.env
      end

      def name
        @name ||= "primary"
      end

      def seed_loader
        @seed_loader ||= Rails.application
      end

      def create(configuration, *arguments)
        db_config = resolve_configuration(configuration)
        database_adapter_for(db_config, *arguments).create
        $stdout.puts "Created database '#{db_config.database}'" if verbose?
      rescue DatabaseAlreadyExists
        $stderr.puts "Database '#{db_config.database}' already exists" if verbose?
      rescue Exception => error
        $stderr.puts error
        $stderr.puts "Couldn't create '#{db_config.database}' database. Please check your configuration."
        raise
      end

      def create_all
        old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base.connection_specification_name)
        each_local_configuration { |db_config| create(db_config) }
        if old_pool
          ActiveRecord::Base.connection_handler.establish_connection(old_pool.db_config)
        end
      end

      def setup_initial_database_yaml
        return {} unless defined?(Rails)

        begin
          Rails.application.config.load_database_yaml
        rescue
          unless ActiveRecord.suppress_multiple_database_warning
            $stderr.puts "Rails couldn't infer whether you are using multiple databases from your database.yml and can't generate the tasks for the non-primary databases. If you'd like to use this feature, please simplify your ERB."
          end

          {}
        end
      end

      def for_each(databases)
        return {} unless defined?(Rails)

        database_configs = ActiveRecord::DatabaseConfigurations.new(databases).configs_for(env_name: Rails.env)

        # if this is a single database application we don't want tasks for each primary database
        return if database_configs.count == 1

        database_configs.each do |db_config|
          next unless db_config.database_tasks?

          yield db_config.name
        end
      end

      def raise_for_multi_db(environment = env, command:)
        db_configs = configs_for(env_name: environment)

        if db_configs.count > 1
          dbs_list = []

          db_configs.each do |db|
            dbs_list << "#{command}:#{db.name}"
          end

          raise "You're using a multiple database application. To use `#{command}` you must run the namespaced task with a VERSION. Available tasks are #{dbs_list.to_sentence}."
        end
      end

      def create_current(environment = env, name = nil)
        each_current_configuration(environment, name) { |db_config| create(db_config) }
        ActiveRecord::Base.establish_connection(environment.to_sym)
      end

      def prepare_all
        seed = false

        configs_for(env_name: env).each do |db_config|
          ActiveRecord::Base.establish_connection(db_config)

          # Skipped when no database
          migrate

          if ActiveRecord.dump_schema_after_migration
            dump_schema(db_config, ActiveRecord.schema_format)
          end
        rescue ActiveRecord::NoDatabaseError
          create_current(db_config.env_name, db_config.name)

          if File.exist?(schema_dump_path(db_config))
            load_schema(
              db_config,
              ActiveRecord.schema_format,
              nil
            )
          else
            migrate
          end

          seed = true
        end

        ActiveRecord::Base.establish_connection
        load_seed if seed
      end

      def drop(configuration, *arguments)
        db_config = resolve_configuration(configuration)
        database_adapter_for(db_config, *arguments).drop
        $stdout.puts "Dropped database '#{db_config.database}'" if verbose?
      rescue ActiveRecord::NoDatabaseError
        $stderr.puts "Database '#{db_config.database}' does not exist"
      rescue Exception => error
        $stderr.puts error
        $stderr.puts "Couldn't drop database '#{db_config.database}'"
        raise
      end

      def drop_all
        each_local_configuration { |db_config| drop(db_config) }
      end

      def drop_current(environment = env)
        each_current_configuration(environment) { |db_config| drop(db_config) }
      end

      def truncate_tables(db_config)
        ActiveRecord::Base.establish_connection(db_config)

        connection = ActiveRecord::Base.connection
        connection.truncate_tables(*connection.tables)
      end
      private :truncate_tables

      def truncate_all(environment = env)
        configs_for(env_name: environment).each do |db_config|
          truncate_tables(db_config)
        end
      end

      def migrate(version = nil)
        check_target_version

        scope = ENV["SCOPE"]
        verbose_was, Migration.verbose = Migration.verbose, verbose?

        Base.connection.migration_context.migrate(target_version) do |migration|
          if version.blank?
            scope.blank? || scope == migration.scope
          else
            migration.version == version
          end
        end.tap do |migrations_ran|
          Migration.write("No migrations ran. (using #{scope} scope)") if scope.present? && migrations_ran.empty?
        end

        ActiveRecord::Base.clear_cache!
      ensure
        Migration.verbose = verbose_was
      end

      def db_configs_with_versions(db_configs) # :nodoc:
        db_configs_with_versions = Hash.new { |h, k| h[k] = [] }

        db_configs.each do |db_config|
          ActiveRecord::Base.establish_connection(db_config)
          versions_to_run = ActiveRecord::Base.connection.migration_context.pending_migration_versions
          target_version = ActiveRecord::Tasks::DatabaseTasks.target_version

          versions_to_run.each do |version|
            next if target_version && target_version != version
            db_configs_with_versions[version] << db_config
          end
        end

        db_configs_with_versions
      end

      def migrate_status
        unless ActiveRecord::Base.connection.schema_migration.table_exists?
          Kernel.abort "Schema migrations table does not exist yet."
        end

        # output
        puts "\ndatabase: #{ActiveRecord::Base.connection_db_config.database}\n\n"
        puts "#{'Status'.center(8)}  #{'Migration ID'.ljust(14)}  Migration Name"
        puts "-" * 50
        ActiveRecord::Base.connection.migration_context.migrations_status.each do |status, version, name|
          puts "#{status.center(8)}  #{version.ljust(14)}  #{name}"
        end
        puts
      end

      def check_target_version
        if target_version && !Migration.valid_version_format?(ENV["VERSION"])
          raise "Invalid format of target version: `VERSION=#{ENV['VERSION']}`"
        end
      end

      def target_version
        ENV["VERSION"].to_i if ENV["VERSION"] && !ENV["VERSION"].empty?
      end

      def charset_current(env_name = env, db_name = name)
        db_config = configs_for(env_name: env_name, name: db_name)
        charset(db_config)
      end

      def charset(configuration, *arguments)
        db_config = resolve_configuration(configuration)
        database_adapter_for(db_config, *arguments).charset
      end

      def collation_current(env_name = env, db_name = name)
        db_config = configs_for(env_name: env_name, name: db_name)
        collation(db_config)
      end

      def collation(configuration, *arguments)
        db_config = resolve_configuration(configuration)
        database_adapter_for(db_config, *arguments).collation
      end

      def purge(configuration)
        db_config = resolve_configuration(configuration)
        database_adapter_for(db_config).purge
      end

      def purge_all
        each_local_configuration { |db_config| purge(db_config) }
      end

      def purge_current(environment = env)
        each_current_configuration(environment) { |db_config| purge(db_config) }
        ActiveRecord::Base.establish_connection(environment.to_sym)
      end

      def structure_dump(configuration, *arguments)
        db_config = resolve_configuration(configuration)
        filename = arguments.delete_at(0)
        flags = structure_dump_flags_for(db_config.adapter)
        database_adapter_for(db_config, *arguments).structure_dump(filename, flags)
      end

      def structure_load(configuration, *arguments)
        db_config = resolve_configuration(configuration)
        filename = arguments.delete_at(0)
        flags = structure_load_flags_for(db_config.adapter)
        database_adapter_for(db_config, *arguments).structure_load(filename, flags)
      end

      def load_schema(db_config, format = ActiveRecord.schema_format, file = nil) # :nodoc:
        file ||= schema_dump_path(db_config, format)

        verbose_was, Migration.verbose = Migration.verbose, verbose? && ENV["VERBOSE"]
        check_schema_file(file)
        ActiveRecord::Base.establish_connection(db_config)

        case format
        when :ruby
          load(file)
        when :sql
          structure_load(db_config, file)
        else
          raise ArgumentError, "unknown format #{format.inspect}"
        end
        ActiveRecord::InternalMetadata.create_table
        ActiveRecord::InternalMetadata[:environment] = db_config.env_name
        ActiveRecord::InternalMetadata[:schema_sha1] = schema_sha1(file)
      ensure
        Migration.verbose = verbose_was
      end

      def schema_up_to_date?(configuration, format = ActiveRecord.schema_format, file = nil)
        db_config = resolve_configuration(configuration)

        file ||= schema_dump_path(db_config)

        return true unless File.exist?(file)

        ActiveRecord::Base.establish_connection(db_config)

        return false unless ActiveRecord::InternalMetadata.enabled?
        return false unless ActiveRecord::InternalMetadata.table_exists?

        ActiveRecord::InternalMetadata[:schema_sha1] == schema_sha1(file)
      end

      def reconstruct_from_schema(db_config, format = ActiveRecord.schema_format, file = nil) # :nodoc:
        file ||= schema_dump_path(db_config, format)

        check_schema_file(file)

        ActiveRecord::Base.establish_connection(db_config)

        if schema_up_to_date?(db_config, format, file)
          truncate_tables(db_config)
        else
          purge(db_config)
          load_schema(db_config, format, file)
        end
      rescue ActiveRecord::NoDatabaseError
        create(db_config)
        load_schema(db_config, format, file)
      end

      def dump_schema(db_config, format = ActiveRecord.schema_format) # :nodoc:
        require "active_record/schema_dumper"
        filename = schema_dump_path(db_config, format)
        connection = ActiveRecord::Base.connection

        FileUtils.mkdir_p(db_dir)
        case format
        when :ruby
          File.open(filename, "w:utf-8") do |file|
            ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, file)
          end
        when :sql
          structure_dump(db_config, filename)
          if connection.schema_migration.table_exists?
            File.open(filename, "a") do |f|
              f.puts connection.dump_schema_information
              f.print "\n"
            end
          end
        end
      end

      def schema_file_type(format = ActiveRecord.schema_format)
        case format
        when :ruby
          "schema.rb"
        when :sql
          "structure.sql"
        end
      end
      deprecate :schema_file_type

      def schema_dump_path(db_config, format = ActiveRecord.schema_format)
        return ENV["SCHEMA"] if ENV["SCHEMA"]

        filename = db_config.schema_dump(format)
        return unless filename

        if File.dirname(filename) == ActiveRecord::Tasks::DatabaseTasks.db_dir
          filename
        else
          File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, filename)
        end
      end

      def cache_dump_filename(db_config_name, schema_cache_path: nil)
        filename = if ActiveRecord::Base.configurations.primary?(db_config_name)
          "schema_cache.yml"
        else
          "#{db_config_name}_schema_cache.yml"
        end

        schema_cache_path || ENV["SCHEMA_CACHE"] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, filename)
      end

      def load_schema_current(format = ActiveRecord.schema_format, file = nil, environment = env)
        each_current_configuration(environment) do |db_config|
          load_schema(db_config, format, file)
        end
        ActiveRecord::Base.establish_connection(environment.to_sym)
      end

      def check_schema_file(filename)
        unless File.exist?(filename)
          message = +%{#{filename} doesn't exist yet. Run `bin/rails db:migrate` to create it, then try again.}
          message << %{ If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded.} if defined?(::Rails.root)
          Kernel.abort message
        end
      end

      def load_seed
        if seed_loader
          seed_loader.load_seed
        else
          raise "You tried to load seed data, but no seed loader is specified. Please specify seed " \
                "loader with ActiveRecord::Tasks::DatabaseTasks.seed_loader = your_seed_loader\n" \
                "Seed loader should respond to load_seed method"
        end
      end

      # Dumps the schema cache in YAML format for the connection into the file
      #
      # ==== Examples:
      #   ActiveRecord::Tasks::DatabaseTasks.dump_schema_cache(ActiveRecord::Base.connection, "tmp/schema_dump.yaml")
      def dump_schema_cache(conn, filename)
        conn.schema_cache.dump_to(filename)
      end

      def clear_schema_cache(filename)
        FileUtils.rm_f filename, verbose: false
      end

      private
        def configs_for(**options)
          Base.configurations.configs_for(**options)
        end

        def resolve_configuration(configuration)
          Base.configurations.resolve(configuration)
        end

        def verbose?
          ENV["VERBOSE"] ? ENV["VERBOSE"] != "false" : true
        end

        # Create a new instance for the specified db configuration object
        # For classes that have been converted to use db_config objects, pass a
        # `DatabaseConfig`, otherwise pass a `Hash`
        def database_adapter_for(db_config, *arguments)
          klass = class_for_adapter(db_config.adapter)
          converted = klass.respond_to?(:using_database_configurations?) && klass.using_database_configurations?

          config = converted ? db_config : db_config.configuration_hash
          klass.new(config, *arguments)
        end

        def class_for_adapter(adapter)
          _key, task = @tasks.reverse_each.detect { |pattern, _task| adapter[pattern] }
          unless task
            raise DatabaseNotSupported, "Rake tasks not supported by '#{adapter}' adapter"
          end
          task.is_a?(String) ? task.constantize : task
        end

        def each_current_configuration(environment, name = nil)
          environments = [environment]
          environments << "test" if environment == "development" && !ENV["SKIP_TEST_DATABASE"] && !ENV["DATABASE_URL"]

          environments.each do |env|
            configs_for(env_name: env).each do |db_config|
              next if name && name != db_config.name

              yield db_config
            end
          end
        end

        def each_local_configuration
          configs_for.each do |db_config|
            next unless db_config.database

            if local_database?(db_config)
              yield db_config
            else
              $stderr.puts "This task only modifies local databases. #{db_config.database} is on a remote host."
            end
          end
        end

        def local_database?(db_config)
          host = db_config.host
          host.blank? || LOCAL_HOSTS.include?(host)
        end

        def schema_sha1(file)
          OpenSSL::Digest::SHA1.hexdigest(File.read(file))
        end

        def structure_dump_flags_for(adapter)
          if structure_dump_flags.is_a?(Hash)
            structure_dump_flags[adapter.to_sym]
          else
            structure_dump_flags
          end
        end

        def structure_load_flags_for(adapter)
          if structure_load_flags.is_a?(Hash)
            structure_load_flags[adapter.to_sym]
          else
            structure_load_flags
          end
        end
    end
  end
end

date.rb

# frozen_string_literal: true

module ActiveRecord
  module Type
    class Date < ActiveModel::Type::Date
      include Internal::Timezone
    end
  end
end

date_time.rb

# frozen_string_literal: true

module ActiveRecord
  module Type
    class DateTime < ActiveModel::Type::DateTime
      include Internal::Timezone
    end
  end
end

decimal.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Decimal < Type::Decimal # :nodoc:
          def infinity(options = {})
            BigDecimal("Infinity") * (options[:negative] ? -1 : 1)
          end
        end
      end
    end
  end
end

decimal_without_scale.rb

# frozen_string_literal: true

module ActiveRecord
  module Type
    class DecimalWithoutScale < ActiveModel::Type::BigInteger # :nodoc:
      def type
        :decimal
      end

      def type_cast_for_schema(value)
        value.to_s.inspect
      end
    end
  end
end

deduplicable.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters # :nodoc:
    module Deduplicable
      extend ActiveSupport::Concern

      module ClassMethods
        def registry
          @registry ||= {}
        end

        def new(*, **)
          super.deduplicate
        end
      end

      def deduplicate
        self.class.registry[self] ||= deduplicated
      end
      alias :-@ :deduplicate

      private
        def deduplicated
          freeze
        end
    end
  end
end

default.rb

# frozen_string_literal: true

module ActiveRecord
  module Scoping
    class DefaultScope # :nodoc:
      attr_reader :scope, :all_queries

      def initialize(scope, all_queries = nil)
        @scope = scope
        @all_queries = all_queries
      end
    end

    module Default
      extend ActiveSupport::Concern

      included do
        # Stores the default scope for the class.
        class_attribute :default_scopes, instance_writer: false, instance_predicate: false, default: []
        class_attribute :default_scope_override, instance_writer: false, instance_predicate: false, default: nil
      end

      module ClassMethods
        # Returns a scope for the model without the previously set scopes.
        #
        #   class Post < ActiveRecord::Base
        #     def self.default_scope
        #       where(published: true)
        #     end
        #   end
        #
        #   Post.all                                  # Fires "SELECT * FROM posts WHERE published = true"
        #   Post.unscoped.all                         # Fires "SELECT * FROM posts"
        #   Post.where(published: false).unscoped.all # Fires "SELECT * FROM posts"
        #
        # This method also accepts a block. All queries inside the block will
        # not use the previously set scopes.
        #
        #   Post.unscoped {
        #     Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
        #   }
        def unscoped(&block)
          block_given? ? relation.scoping(&block) : relation
        end

        # Are there attributes associated with this scope?
        def scope_attributes? # :nodoc:
          super || default_scopes.any? || respond_to?(:default_scope)
        end

        def before_remove_const # :nodoc:
          self.current_scope = nil
        end

        # Checks if the model has any default scopes. If all_queries
        # is set to true, the method will check if there are any
        # default_scopes for the model  where +all_queries+ is true.
        def default_scopes?(all_queries: false)
          if all_queries
            self.default_scopes.any?(&:all_queries)
          else
            self.default_scopes.any?
          end
        end

        private
          # Use this macro in your model to set a default scope for all operations on
          # the model.
          #
          #   class Article < ActiveRecord::Base
          #     default_scope { where(published: true) }
          #   end
          #
          #   Article.all # => SELECT * FROM articles WHERE published = true
          #
          # The #default_scope is also applied while creating/building a record.
          # It is not applied while updating or deleting a record.
          #
          #   Article.new.published    # => true
          #   Article.create.published # => true
          #
          # To apply a #default_scope when updating or deleting a record, add
          # <tt>all_queries: true</tt>:
          #
          #   class Article < ActiveRecord::Base
          #     default_scope -> { where(blog_id: 1) }, all_queries: true
          #   end
          #
          # Applying a default scope to all queries will ensure that records
          # are always queried by the additional conditions. Note that only
          # where clauses apply, as it does not make sense to add order to
          # queries that return a single object by primary key.
          #
          #   Article.find(1).destroy
          #   => DELETE ... FROM `articles` where ID = 1 AND blog_id = 1;
          #
          # (You can also pass any object which responds to +call+ to the
          # +default_scope+ macro, and it will be called when building the
          # default scope.)
          #
          # If you use multiple #default_scope declarations in your model then
          # they will be merged together:
          #
          #   class Article < ActiveRecord::Base
          #     default_scope { where(published: true) }
          #     default_scope { where(rating: 'G') }
          #   end
          #
          #   Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
          #
          # This is also the case with inheritance and module includes where the
          # parent or module defines a #default_scope and the child or including
          # class defines a second one.
          #
          # If you need to do more complex things with a default scope, you can
          # alternatively define it as a class method:
          #
          #   class Article < ActiveRecord::Base
          #     def self.default_scope
          #       # Should return a scope, you can call 'super' here etc.
          #     end
          #   end
          def default_scope(scope = nil, all_queries: nil, &block) # :doc:
            scope = block if block_given?

            if scope.is_a?(Relation) || !scope.respond_to?(:call)
              raise ArgumentError,
                "Support for calling #default_scope without a block is removed. For example instead " \
                "of `default_scope where(color: 'red')`, please use " \
                "`default_scope { where(color: 'red') }`. (Alternatively you can just redefine " \
                "self.default_scope.)"
            end

            default_scope = DefaultScope.new(scope, all_queries)

            self.default_scopes += [default_scope]
          end

          def build_default_scope(relation = relation(), all_queries: nil)
            return if abstract_class?

            if default_scope_override.nil?
              self.default_scope_override = !Base.is_a?(method(:default_scope).owner)
            end

            if default_scope_override
              # The user has defined their own default scope method, so call that
              evaluate_default_scope do
                relation.scoping { default_scope }
              end
            elsif default_scopes.any?
              evaluate_default_scope do
                default_scopes.inject(relation) do |default_scope, scope_obj|
                  if execute_scope?(all_queries, scope_obj)
                    scope = scope_obj.scope.respond_to?(:to_proc) ? scope_obj.scope : scope_obj.scope.method(:call)

                    default_scope.instance_exec(&scope) || default_scope
                  end
                end
              end
            end
          end

          # If all_queries is nil, only execute on select and insert queries.
          #
          # If all_queries is true, check if the default_scope object has
          # all_queries set, then execute on all queries; select, insert, update
          # and delete.
          def execute_scope?(all_queries, default_scope_obj)
            all_queries.nil? || all_queries && default_scope_obj.all_queries
          end

          def ignore_default_scope?
            ScopeRegistry.ignore_default_scope(base_class)
          end

          def ignore_default_scope=(ignore)
            ScopeRegistry.set_ignore_default_scope(base_class, ignore)
          end

          # The ignore_default_scope flag is used to prevent an infinite recursion
          # situation where a default scope references a scope which has a default
          # scope which references a scope...
          def evaluate_default_scope
            return if ignore_default_scope?

            begin
              self.ignore_default_scope = true
              yield
            ensure
              self.ignore_default_scope = false
            end
          end
      end
    end
  end
end

delegated_type.rb

# frozen_string_literal: true

require "active_support/core_ext/string/inquiry"

module ActiveRecord
  # == Delegated types
  #
  # Class hierarchies can map to relational database tables in many ways. Active Record, for example, offers
  # purely abstract classes, where the superclass doesn't persist any attributes, and single-table inheritance,
  # where all attributes from all levels of the hierarchy are represented in a single table. Both have their
  # places, but neither are without their drawbacks.
  #
  # The problem with purely abstract classes is that all concrete subclasses must persist all the shared
  # attributes themselves in their own tables (also known as class-table inheritance). This makes it hard to
  # do queries across the hierarchy. For example, imagine you have the following hierarchy:
  #
  #   Entry < ApplicationRecord
  #   Message < Entry
  #   Comment < Entry
  #
  # How do you show a feed that has both +Message+ and +Comment+ records, which can be easily paginated?
  # Well, you can't! Messages are backed by a messages table and comments by a comments table. You can't
  # pull from both tables at once and use a consistent OFFSET/LIMIT scheme.
  #
  # You can get around the pagination problem by using single-table inheritance, but now you're forced into
  # a single mega table with all the attributes from all subclasses. No matter how divergent. If a Message
  # has a subject, but the comment does not, well, now the comment does anyway! So STI works best when there's
  # little divergence between the subclasses and their attributes.
  #
  # But there's a third way: Delegated types. With this approach, the "superclass" is a concrete class
  # that is represented by its own table, where all the superclass attributes that are shared amongst all the
  # "subclasses" are stored. And then each of the subclasses have their own individual tables for additional
  # attributes that are particular to their implementation. This is similar to what's called multi-table
  # inheritance in Django, but instead of actual inheritance, this approach uses delegation to form the
  # hierarchy and share responsibilities.
  #
  # Let's look at that entry/message/comment example using delegated types:
  #
  #   # Schema: entries[ id, account_id, creator_id, created_at, updated_at, entryable_type, entryable_id ]
  #   class Entry < ApplicationRecord
  #     belongs_to :account
  #     belongs_to :creator
  #     delegated_type :entryable, types: %w[ Message Comment ]
  #   end
  #
  #   module Entryable
  #     extend ActiveSupport::Concern
  #
  #     included do
  #       has_one :entry, as: :entryable, touch: true
  #     end
  #   end
  #
  #   # Schema: messages[ id, subject, body ]
  #   class Message < ApplicationRecord
  #     include Entryable
  #   end
  #
  #   # Schema: comments[ id, content ]
  #   class Comment < ApplicationRecord
  #     include Entryable
  #   end
  #
  # As you can see, neither +Message+ nor +Comment+ are meant to stand alone. Crucial metadata for both classes
  # resides in the +Entry+ "superclass". But the +Entry+ absolutely can stand alone in terms of querying capacity
  # in particular. You can now easily do things like:
  #
  #   Account.find(1).entries.order(created_at: :desc).limit(50)
  #
  # Which is exactly what you want when displaying both comments and messages together. The entry itself can
  # be rendered as its delegated type easily, like so:
  #
  #   # entries/_entry.html.erb
  #   <%= render "entries/entryables/#{entry.entryable_name}", entry: entry %>
  #
  #   # entries/entryables/_message.html.erb
  #   <div class="message">
  #     <div class="subject"><%= entry.message.subject %></div>
  #     <p><%= entry.message.body %></p>
  #     <i>Posted on <%= entry.created_at %> by <%= entry.creator.name %></i>
  #   </div>
  #
  #   # entries/entryables/_comment.html.erb
  #   <div class="comment">
  #     <%= entry.creator.name %> said: <%= entry.comment.content %>
  #   </div>
  #
  # == Sharing behavior with concerns and controllers
  #
  # The entry "superclass" also serves as a perfect place to put all that shared logic that applies to both
  # messages and comments, and which acts primarily on the shared attributes. Imagine:
  #
  #   class Entry < ApplicationRecord
  #     include Eventable, Forwardable, Redeliverable
  #   end
  #
  # Which allows you to have controllers for things like +ForwardsController+ and +RedeliverableController+
  # that both act on entries, and thus provide the shared functionality to both messages and comments.
  #
  # == Creating new records
  #
  # You create a new record that uses delegated typing by creating the delegator and delegatee at the same time,
  # like so:
  #
  #   Entry.create! entryable: Comment.new(content: "Hello!"), creator: Current.user
  #
  # If you need more complicated composition, or you need to perform dependent validation, you should build a factory
  # method or class to take care of the complicated needs. This could be as simple as:
  #
  #   class Entry < ApplicationRecord
  #     def self.create_with_comment(content, creator: Current.user)
  #       create! entryable: Comment.new(content: content), creator: creator
  #     end
  #   end
  #
  # == Adding further delegation
  #
  # The delegated type shouldn't just answer the question of what the underlying class is called. In fact, that's
  # an anti-pattern most of the time. The reason you're building this hierarchy is to take advantage of polymorphism.
  # So here's a simple example of that:
  #
  #   class Entry < ApplicationRecord
  #     delegated_type :entryable, types: %w[ Message Comment ]
  #     delegate :title, to: :entryable
  #   end
  #
  #   class Message < ApplicationRecord
  #     def title
  #       subject
  #     end
  #   end
  #
  #   class Comment < ApplicationRecord
  #     def title
  #       content.truncate(20)
  #     end
  #   end
  #
  # Now you can list a bunch of entries, call +Entry#title+, and polymorphism will provide you with the answer.
  #
  # == Nested Attributes
  #
  # Enabling nested attributes on a delegated_type association allows you to
  # create the entry and message in one go:
  #
  #   class Entry < ApplicationRecord
  #     delegated_type :entryable, types: %w[ Message Comment ]
  #     accepts_nested_attributes_for :entryable
  #   end
  #
  #   params = { entry: { entryable_type: 'Message', entryable_attributes: { subject: 'Smiling' } } }
  #   entry = Entry.create(params[:entry])
  #   entry.entryable.id # => 2
  #   entry.entryable.subject # => 'Smiling'
  module DelegatedType
    # Defines this as a class that'll delegate its type for the passed +role+ to the class references in +types+.
    # That'll create a polymorphic +belongs_to+ relationship to that +role+, and it'll add all the delegated
    # type convenience methods:
    #
    #   class Entry < ApplicationRecord
    #     delegated_type :entryable, types: %w[ Message Comment ], dependent: :destroy
    #   end
    #
    #   Entry#entryable_class # => +Message+ or +Comment+
    #   Entry#entryable_name  # => "message" or "comment"
    #   Entry.messages        # => Entry.where(entryable_type: "Message")
    #   Entry#message?        # => true when entryable_type == "Message"
    #   Entry#message         # => returns the message record, when entryable_type == "Message", otherwise nil
    #   Entry#message_id      # => returns entryable_id, when entryable_type == "Message", otherwise nil
    #   Entry.comments        # => Entry.where(entryable_type: "Comment")
    #   Entry#comment?        # => true when entryable_type == "Comment"
    #   Entry#comment         # => returns the comment record, when entryable_type == "Comment", otherwise nil
    #   Entry#comment_id      # => returns entryable_id, when entryable_type == "Comment", otherwise nil
    #
    # You can also declare namespaced types:
    #
    #   class Entry < ApplicationRecord
    #     delegated_type :entryable, types: %w[ Message Comment Access::NoticeMessage ], dependent: :destroy
    #   end
    #
    #   Entry.access_notice_messages
    #   entry.access_notice_message
    #   entry.access_notice_message?
    #
    # === Options
    #
    # The +options+ are passed directly to the +belongs_to+ call, so this is where you declare +dependent+ etc.
    # The following options can be included to specialize the behavior of the delegated type convenience methods.
    #
    # [:foreign_key]
    #   Specify the foreign key used for the convenience methods. By default this is guessed to be the passed
    #   +role+ with an "_id" suffix. So a class that defines a
    #   <tt>delegated_type :entryable, types: %w[ Message Comment ]</tt> association will use "entryable_id" as
    #   the default <tt>:foreign_key</tt>.
    # [:primary_key]
    #   Specify the method that returns the primary key of associated object used for the convenience methods.
    #   By default this is +id+.
    #
    # Option examples:
    #   class Entry < ApplicationRecord
    #     delegated_type :entryable, types: %w[ Message Comment ], primary_key: :uuid, foreign_key: :entryable_uuid
    #   end
    #
    #   Entry#message_uuid      # => returns entryable_uuid, when entryable_type == "Message", otherwise nil
    #   Entry#comment_uuid      # => returns entryable_uuid, when entryable_type == "Comment", otherwise nil
    def delegated_type(role, types:, **options)
      belongs_to role, options.delete(:scope), **options.merge(polymorphic: true)
      define_delegated_type_methods role, types: types, options: options
    end

    private
      def define_delegated_type_methods(role, types:, options:)
        primary_key = options[:primary_key] || "id"
        role_type = "#{role}_type"
        role_id   = options[:foreign_key] || "#{role}_id"

        define_method "#{role}_class" do
          public_send("#{role}_type").constantize
        end

        define_method "#{role}_name" do
          public_send("#{role}_class").model_name.singular.inquiry
        end

        define_method "build_#{role}" do |*params|
          public_send("#{role}=", public_send("#{role}_class").new(*params))
        end

        types.each do |type|
          scope_name = type.tableize.tr("/", "_")
          singular   = scope_name.singularize
          query      = "#{singular}?"

          scope scope_name, -> { where(role_type => type) }

          define_method query do
            public_send(role_type) == type
          end

          define_method singular do
            public_send(role) if public_send(query)
          end

          define_method "#{singular}_#{primary_key}" do
            public_send(role_id) if public_send(query)
          end
        end
      end
  end
end

delegation.rb

# frozen_string_literal: true

require "mutex_m"
require "active_support/core_ext/module/delegation"

module ActiveRecord
  module Delegation # :nodoc:
    module DelegateCache # :nodoc:
      def relation_delegate_class(klass)
        @relation_delegate_cache[klass]
      end

      def initialize_relation_delegate_cache
        @relation_delegate_cache = cache = {}
        [
          ActiveRecord::Relation,
          ActiveRecord::Associations::CollectionProxy,
          ActiveRecord::AssociationRelation,
          ActiveRecord::DisableJoinsAssociationRelation
        ].each do |klass|
          delegate = Class.new(klass) {
            include ClassSpecificRelation
          }
          include_relation_methods(delegate)
          mangled_name = klass.name.gsub("::", "_")
          const_set mangled_name, delegate
          private_constant mangled_name

          cache[klass] = delegate
        end
      end

      def inherited(child_class)
        child_class.initialize_relation_delegate_cache
        super
      end

      def generate_relation_method(method)
        generated_relation_methods.generate_method(method)
      end

      protected
        def include_relation_methods(delegate)
          superclass.include_relation_methods(delegate) unless base_class?
          delegate.include generated_relation_methods
        end

      private
        def generated_relation_methods
          @generated_relation_methods ||= GeneratedRelationMethods.new.tap do |mod|
            const_set(:GeneratedRelationMethods, mod)
            private_constant :GeneratedRelationMethods
          end
        end
    end

    class GeneratedRelationMethods < Module # :nodoc:
      include Mutex_m

      def generate_method(method)
        synchronize do
          return if method_defined?(method)

          if /\A[a-zA-Z_]\w*[!?]?\z/.match?(method) && !DELEGATION_RESERVED_METHOD_NAMES.include?(method.to_s)
            module_eval <<-RUBY, __FILE__, __LINE__ + 1
              def #{method}(...)
                scoping { klass.#{method}(...) }
              end
            RUBY
          else
            define_method(method) do |*args, &block|
              scoping { klass.public_send(method, *args, &block) }
            end
            ruby2_keywords(method)
          end
        end
      end
    end
    private_constant :GeneratedRelationMethods

    extend ActiveSupport::Concern

    # This module creates compiled delegation methods dynamically at runtime, which makes
    # subsequent calls to that method faster by avoiding method_missing. The delegations
    # may vary depending on the klass of a relation, so we create a subclass of Relation
    # for each different klass, and the delegations are compiled into that subclass only.

    delegate :to_xml, :encode_with, :length, :each, :join,
             :[], :&, :|, :+, :-, :sample, :reverse, :rotate, :compact, :in_groups, :in_groups_of,
             :to_sentence, :to_fs, :to_formatted_s, :as_json,
             :shuffle, :split, :slice, :index, :rindex, to: :records

    delegate :primary_key, :connection, to: :klass

    module ClassSpecificRelation # :nodoc:
      extend ActiveSupport::Concern

      module ClassMethods # :nodoc:
        def name
          superclass.name
        end
      end

      private
        def method_missing(method, *args, &block)
          if @klass.respond_to?(method)
            @klass.generate_relation_method(method)
            scoping { @klass.public_send(method, *args, &block) }
          else
            super
          end
        end
        ruby2_keywords(:method_missing)
    end

    module ClassMethods # :nodoc:
      def create(klass, *args, **kwargs)
        relation_class_for(klass).new(klass, *args, **kwargs)
      end

      private
        def relation_class_for(klass)
          klass.relation_delegate_class(self)
        end
    end

    private
      def respond_to_missing?(method, _)
        super || @klass.respond_to?(method)
      end
  end
end

delete_manager.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  class DeleteManager < Arel::TreeManager
    include TreeManager::StatementMethods

    def initialize(table = nil)
      @ast = Nodes::DeleteStatement.new(table)
    end

    def from(relation)
      @ast.relation = relation
      self
    end

    def group(columns)
      columns.each do |column|
        column = Nodes::SqlLiteral.new(column) if String === column
        column = Nodes::SqlLiteral.new(column.to_s) if Symbol === column

        @ast.groups.push Nodes::Group.new column
      end

      self
    end

    def having(expr)
      @ast.havings << expr
      self
    end
  end
end

delete_statement.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class DeleteStatement < Arel::Nodes::Node
      attr_accessor :relation, :wheres, :groups, :havings, :orders, :limit, :offset, :key

      def initialize(relation = nil, wheres = [])
        super()
        @relation = relation
        @wheres = wheres
        @groups = []
        @havings = []
        @orders = []
        @limit = nil
        @offset = nil
        @key = nil
      end

      def initialize_copy(other)
        super
        @relation = @relation.clone if @relation
        @wheres = @wheres.clone if @wheres
      end

      def hash
        [self.class, @relation, @wheres, @orders, @limit, @offset, @key].hash
      end

      def eql?(other)
        self.class == other.class &&
          self.relation == other.relation &&
          self.wheres == other.wheres &&
          self.orders == other.orders &&
          self.groups == other.groups &&
          self.havings == other.havings &&
          self.limit == other.limit &&
          self.offset == other.offset &&
          self.key == other.key
      end
      alias :== :eql?
    end
  end
end

derived_secret_key_provider.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # A KeyProvider that derives keys from passwords.
    class DerivedSecretKeyProvider < KeyProvider
      def initialize(passwords)
        super(Array(passwords).collect { |password| Key.derive_from(password) })
      end
    end
  end
end

descending.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Descending < Ordering
      def reverse
        Ascending.new(expr)
      end

      def direction
        :desc
      end

      def ascending?
        false
      end

      def descending?
        true
      end
    end
  end
end

destroy_association_async_job.rb

# frozen_string_literal: true

module ActiveRecord
  class DestroyAssociationAsyncError < StandardError
  end

  # Job to destroy the records associated with a destroyed record in background.
  class DestroyAssociationAsyncJob < ActiveJob::Base
    queue_as { ActiveRecord.queues[:destroy] }

    discard_on ActiveJob::DeserializationError

    def perform(
      owner_model_name: nil, owner_id: nil,
      association_class: nil, association_ids: nil, association_primary_key_column: nil,
      ensuring_owner_was_method: nil
    )
      association_model = association_class.constantize
      owner_class = owner_model_name.constantize
      owner = owner_class.find_by(owner_class.primary_key.to_sym => owner_id)

      if !owner_destroyed?(owner, ensuring_owner_was_method)
        raise DestroyAssociationAsyncError, "owner record not destroyed"
      end

      association_model.where(association_primary_key_column => association_ids).find_each do |r|
        r.destroy
      end
    end

    private
      def owner_destroyed?(owner, ensuring_owner_was_method)
        !owner || (ensuring_owner_was_method && owner.public_send(ensuring_owner_was_method))
      end
  end
end

deterministic_key_provider.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # A KeyProvider that derives keys from passwords.
    class DeterministicKeyProvider < DerivedSecretKeyProvider
      def initialize(password)
        passwords = Array(password)
        raise ActiveRecord::Encryption::Errors::Configuration, "Deterministic encryption keys can't be rotated" if passwords.length > 1
        super(passwords)
      end
    end
  end
end

dirty.rb

# frozen_string_literal: true

require "active_support/core_ext/module/attribute_accessors"

module ActiveRecord
  module AttributeMethods
    module Dirty
      extend ActiveSupport::Concern

      include ActiveModel::Dirty

      included do
        if self < ::ActiveRecord::Timestamp
          raise "You cannot include Dirty after Timestamp"
        end

        class_attribute :partial_updates, instance_writer: false, default: true
        class_attribute :partial_inserts, instance_writer: false, default: true

        # Attribute methods for "changed in last call to save?"
        attribute_method_affix(prefix: "saved_change_to_", suffix: "?", parameters: "**options")
        attribute_method_prefix("saved_change_to_", parameters: false)
        attribute_method_suffix("_before_last_save", parameters: false)

        # Attribute methods for "will change if I call save?"
        attribute_method_affix(prefix: "will_save_change_to_", suffix: "?", parameters: "**options")
        attribute_method_suffix("_change_to_be_saved", "_in_database", parameters: false)
      end

      module ClassMethods
        def partial_writes
          ActiveSupport::Deprecation.warn(<<-MSG.squish)
            ActiveRecord::Base.partial_writes is deprecated and will be removed in Rails 7.1.
            Use `partial_updates` and `partial_inserts` instead.
          MSG
          partial_updates && partial_inserts
        end

        def partial_writes?
          ActiveSupport::Deprecation.warn(<<-MSG.squish)
            `ActiveRecord::Base.partial_writes?` is deprecated and will be removed in Rails 7.1.
            Use `partial_updates?` and `partial_inserts?` instead.
          MSG
          partial_updates? && partial_inserts?
        end

        def partial_writes=(value)
          ActiveSupport::Deprecation.warn(<<-MSG.squish)
            `ActiveRecord::Base.partial_writes=` is deprecated and will be removed in Rails 7.1.
            Use `partial_updates=` and `partial_inserts=` instead.
          MSG
          self.partial_updates = self.partial_inserts = value
        end
      end

      # <tt>reload</tt> the record and clears changed attributes.
      def reload(*)
        super.tap do
          @mutations_before_last_save = nil
          @mutations_from_database = nil
        end
      end

      # Did this attribute change when we last saved?
      #
      # This method is useful in after callbacks to determine if an attribute
      # was changed during the save that triggered the callbacks to run. It can
      # be invoked as +saved_change_to_name?+ instead of
      # <tt>saved_change_to_attribute?("name")</tt>.
      #
      # ==== Options
      #
      # +from+ When passed, this method will return false unless the original
      # value is equal to the given option
      #
      # +to+ When passed, this method will return false unless the value was
      # changed to the given value
      def saved_change_to_attribute?(attr_name, **options)
        mutations_before_last_save.changed?(attr_name.to_s, **options)
      end

      # Returns the change to an attribute during the last save. If the
      # attribute was changed, the result will be an array containing the
      # original value and the saved value.
      #
      # This method is useful in after callbacks, to see the change in an
      # attribute during the save that triggered the callbacks to run. It can be
      # invoked as +saved_change_to_name+ instead of
      # <tt>saved_change_to_attribute("name")</tt>.
      def saved_change_to_attribute(attr_name)
        mutations_before_last_save.change_to_attribute(attr_name.to_s)
      end

      # Returns the original value of an attribute before the last save.
      #
      # This method is useful in after callbacks to get the original value of an
      # attribute before the save that triggered the callbacks to run. It can be
      # invoked as +name_before_last_save+ instead of
      # <tt>attribute_before_last_save("name")</tt>.
      def attribute_before_last_save(attr_name)
        mutations_before_last_save.original_value(attr_name.to_s)
      end

      # Did the last call to +save+ have any changes to change?
      def saved_changes?
        mutations_before_last_save.any_changes?
      end

      # Returns a hash containing all the changes that were just saved.
      def saved_changes
        mutations_before_last_save.changes
      end

      # Will this attribute change the next time we save?
      #
      # This method is useful in validations and before callbacks to determine
      # if the next call to +save+ will change a particular attribute. It can be
      # invoked as +will_save_change_to_name?+ instead of
      # <tt>will_save_change_to_attribute?("name")</tt>.
      #
      # ==== Options
      #
      # +from+ When passed, this method will return false unless the original
      # value is equal to the given option
      #
      # +to+ When passed, this method will return false unless the value will be
      # changed to the given value
      def will_save_change_to_attribute?(attr_name, **options)
        mutations_from_database.changed?(attr_name.to_s, **options)
      end

      # Returns the change to an attribute that will be persisted during the
      # next save.
      #
      # This method is useful in validations and before callbacks, to see the
      # change to an attribute that will occur when the record is saved. It can
      # be invoked as +name_change_to_be_saved+ instead of
      # <tt>attribute_change_to_be_saved("name")</tt>.
      #
      # If the attribute will change, the result will be an array containing the
      # original value and the new value about to be saved.
      def attribute_change_to_be_saved(attr_name)
        mutations_from_database.change_to_attribute(attr_name.to_s)
      end

      # Returns the value of an attribute in the database, as opposed to the
      # in-memory value that will be persisted the next time the record is
      # saved.
      #
      # This method is useful in validations and before callbacks, to see the
      # original value of an attribute prior to any changes about to be
      # saved. It can be invoked as +name_in_database+ instead of
      # <tt>attribute_in_database("name")</tt>.
      def attribute_in_database(attr_name)
        mutations_from_database.original_value(attr_name.to_s)
      end

      # Will the next call to +save+ have any changes to persist?
      def has_changes_to_save?
        mutations_from_database.any_changes?
      end

      # Returns a hash containing all the changes that will be persisted during
      # the next save.
      def changes_to_save
        mutations_from_database.changes
      end

      # Returns an array of the names of any attributes that will change when
      # the record is next saved.
      def changed_attribute_names_to_save
        mutations_from_database.changed_attribute_names
      end

      # Returns a hash of the attributes that will change when the record is
      # next saved.
      #
      # The hash keys are the attribute names, and the hash values are the
      # original attribute values in the database (as opposed to the in-memory
      # values about to be saved).
      def attributes_in_database
        mutations_from_database.changed_values
      end

      private
        def _touch_row(attribute_names, time)
          @_touch_attr_names = Set.new(attribute_names)

          affected_rows = super

          if @_skip_dirty_tracking ||= false
            clear_attribute_changes(@_touch_attr_names)
            return affected_rows
          end

          changes = {}
          @attributes.keys.each do |attr_name|
            next if @_touch_attr_names.include?(attr_name)

            if attribute_changed?(attr_name)
              changes[attr_name] = _read_attribute(attr_name)
              _write_attribute(attr_name, attribute_was(attr_name))
              clear_attribute_change(attr_name)
            end
          end

          changes_applied
          changes.each { |attr_name, value| _write_attribute(attr_name, value) }

          affected_rows
        ensure
          @_touch_attr_names, @_skip_dirty_tracking = nil, nil
        end

        def _update_record(attribute_names = attribute_names_for_partial_updates)
          affected_rows = super
          changes_applied
          affected_rows
        end

        def _create_record(attribute_names = attribute_names_for_partial_inserts)
          id = super
          changes_applied
          id
        end

        def attribute_names_for_partial_updates
          partial_updates? ? changed_attribute_names_to_save : attribute_names
        end

        def attribute_names_for_partial_inserts
          if partial_inserts?
            changed_attribute_names_to_save
          else
            attribute_names.reject do |attr_name|
              if column_for_attribute(attr_name).default_function
                !attribute_changed?(attr_name)
              end
            end
          end
        end
    end
  end
end

disable_joins_association_relation.rb

# frozen_string_literal: true

module ActiveRecord
  class DisableJoinsAssociationRelation < Relation # :nodoc:
    attr_reader :ids, :key

    def initialize(klass, key, ids)
      @ids = ids.uniq
      @key = key
      super(klass)
    end

    def limit(value)
      records.take(value)
    end

    def first(limit = nil)
      if limit
        records.limit(limit).first
      else
        records.first
      end
    end

    def load
      super
      records = @records

      records_by_id = records.group_by do |record|
        record[key]
      end

      records = ids.flat_map { |id| records_by_id[id.to_i] }
      records.compact!

      @records = records
    end
  end
end

disable_joins_association_scope.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class DisableJoinsAssociationScope < AssociationScope # :nodoc:
      def scope(association)
        source_reflection = association.reflection
        owner = association.owner
        unscoped = association.klass.unscoped
        reverse_chain = get_chain(source_reflection, association, unscoped.alias_tracker).reverse

        last_reflection, last_ordered, last_join_ids = last_scope_chain(reverse_chain, owner)

        add_constraints(last_reflection, last_reflection.join_primary_key, last_join_ids, owner, last_ordered)
      end

      private
        def last_scope_chain(reverse_chain, owner)
          first_item = reverse_chain.shift
          first_scope = [first_item, false, [owner._read_attribute(first_item.join_foreign_key)]]

          reverse_chain.inject(first_scope) do |(reflection, ordered, join_ids), next_reflection|
            key = reflection.join_primary_key
            records = add_constraints(reflection, key, join_ids, owner, ordered)
            foreign_key = next_reflection.join_foreign_key
            record_ids = records.pluck(foreign_key)
            records_ordered = records && records.order_values.any?

            [next_reflection, records_ordered, record_ids]
          end
        end

        def add_constraints(reflection, key, join_ids, owner, ordered)
          scope = reflection.build_scope(reflection.aliased_table).where(key => join_ids)

          relation = reflection.klass.scope_for_association
          scope.merge!(
            relation.except(:select, :create_with, :includes, :preload, :eager_load, :joins, :left_outer_joins)
          )

          scope = reflection.constraints.inject(scope) do |memo, scope_chain_item|
            item = eval_scope(reflection, scope_chain_item, owner)
            scope.unscope!(*item.unscope_values)
            scope.where_clause += item.where_clause
            scope.order_values = item.order_values | scope.order_values
            scope
          end

          if scope.order_values.empty? && ordered
            split_scope = DisableJoinsAssociationRelation.create(scope.klass, key, join_ids)
            split_scope.where_clause += scope.where_clause
            split_scope
          else
            scope
          end
        end
    end
  end
end

dot.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Visitors
    class Dot < Arel::Visitors::Visitor
      class Node # :nodoc:
        attr_accessor :name, :id, :fields

        def initialize(name, id, fields = [])
          @name   = name
          @id     = id
          @fields = fields
        end
      end

      class Edge < Struct.new :name, :from, :to # :nodoc:
      end

      def initialize
        super()
        @nodes      = []
        @edges      = []
        @node_stack = []
        @edge_stack = []
        @seen       = {}
      end

      def accept(object, collector)
        visit object
        collector << to_dot
      end

      private
        def visit_Arel_Nodes_Function(o)
          visit_edge o, "expressions"
          visit_edge o, "distinct"
          visit_edge o, "alias"
        end

        def visit_Arel_Nodes_Unary(o)
          visit_edge o, "expr"
        end

        def visit_Arel_Nodes_Binary(o)
          visit_edge o, "left"
          visit_edge o, "right"
        end

        def visit_Arel_Nodes_UnaryOperation(o)
          visit_edge o, "operator"
          visit_edge o, "expr"
        end

        def visit_Arel_Nodes_InfixOperation(o)
          visit_edge o, "operator"
          visit_edge o, "left"
          visit_edge o, "right"
        end

        def visit__regexp(o)
          visit_edge o, "left"
          visit_edge o, "right"
          visit_edge o, "case_sensitive"
        end
        alias :visit_Arel_Nodes_Regexp :visit__regexp
        alias :visit_Arel_Nodes_NotRegexp :visit__regexp

        def visit_Arel_Nodes_Ordering(o)
          visit_edge o, "expr"
        end

        def visit_Arel_Nodes_TableAlias(o)
          visit_edge o, "name"
          visit_edge o, "relation"
        end

        def visit_Arel_Nodes_Count(o)
          visit_edge o, "expressions"
          visit_edge o, "distinct"
        end

        def visit_Arel_Nodes_ValuesList(o)
          visit_edge o, "rows"
        end

        def visit_Arel_Nodes_StringJoin(o)
          visit_edge o, "left"
        end

        def visit_Arel_Nodes_Window(o)
          visit_edge o, "partitions"
          visit_edge o, "orders"
          visit_edge o, "framing"
        end

        def visit_Arel_Nodes_NamedWindow(o)
          visit_edge o, "partitions"
          visit_edge o, "orders"
          visit_edge o, "framing"
          visit_edge o, "name"
        end

        def visit__no_edges(o)
          # intentionally left blank
        end
        alias :visit_Arel_Nodes_CurrentRow :visit__no_edges
        alias :visit_Arel_Nodes_Distinct :visit__no_edges

        def visit_Arel_Nodes_Extract(o)
          visit_edge o, "expressions"
          visit_edge o, "alias"
        end

        def visit_Arel_Nodes_NamedFunction(o)
          visit_edge o, "name"
          visit_edge o, "expressions"
          visit_edge o, "distinct"
          visit_edge o, "alias"
        end

        def visit_Arel_Nodes_InsertStatement(o)
          visit_edge o, "relation"
          visit_edge o, "columns"
          visit_edge o, "values"
          visit_edge o, "select"
        end

        def visit_Arel_Nodes_SelectCore(o)
          visit_edge o, "source"
          visit_edge o, "projections"
          visit_edge o, "wheres"
          visit_edge o, "windows"
          visit_edge o, "groups"
          visit_edge o, "comment"
          visit_edge o, "havings"
          visit_edge o, "set_quantifier"
          visit_edge o, "optimizer_hints"
        end

        def visit_Arel_Nodes_SelectStatement(o)
          visit_edge o, "cores"
          visit_edge o, "limit"
          visit_edge o, "orders"
          visit_edge o, "offset"
          visit_edge o, "lock"
          visit_edge o, "with"
        end

        def visit_Arel_Nodes_UpdateStatement(o)
          visit_edge o, "relation"
          visit_edge o, "wheres"
          visit_edge o, "values"
          visit_edge o, "orders"
          visit_edge o, "limit"
          visit_edge o, "offset"
          visit_edge o, "key"
        end

        def visit_Arel_Nodes_DeleteStatement(o)
          visit_edge o, "relation"
          visit_edge o, "wheres"
          visit_edge o, "orders"
          visit_edge o, "limit"
          visit_edge o, "offset"
          visit_edge o, "key"
        end

        def visit_Arel_Table(o)
          visit_edge o, "name"
        end

        def visit_Arel_Nodes_Casted(o)
          visit_edge o, "value"
          visit_edge o, "attribute"
        end

        def visit_Arel_Nodes_HomogeneousIn(o)
          visit_edge o, "values"
          visit_edge o, "type"
          visit_edge o, "attribute"
        end

        def visit_Arel_Attributes_Attribute(o)
          visit_edge o, "relation"
          visit_edge o, "name"
        end

        def visit__children(o)
          o.children.each_with_index do |child, i|
            edge(i) { visit child }
          end
        end
        alias :visit_Arel_Nodes_And :visit__children
        alias :visit_Arel_Nodes_With :visit__children

        def visit_String(o)
          @node_stack.last.fields << o
        end
        alias :visit_Time :visit_String
        alias :visit_Date :visit_String
        alias :visit_DateTime :visit_String
        alias :visit_NilClass :visit_String
        alias :visit_TrueClass :visit_String
        alias :visit_FalseClass :visit_String
        alias :visit_Integer :visit_String
        alias :visit_BigDecimal :visit_String
        alias :visit_Float :visit_String
        alias :visit_Symbol :visit_String
        alias :visit_Arel_Nodes_SqlLiteral :visit_String

        def visit_Arel_Nodes_BindParam(o)
          visit_edge(o, "value")
        end

        def visit_ActiveModel_Attribute(o)
          visit_edge(o, "value_before_type_cast")
        end

        def visit_Hash(o)
          o.each_with_index do |pair, i|
            edge("pair_#{i}") { visit pair }
          end
        end

        def visit_Array(o)
          o.each_with_index do |member, i|
            edge(i) { visit member }
          end
        end
        alias :visit_Set :visit_Array

        def visit_Arel_Nodes_Comment(o)
          visit_edge(o, "values")
        end

        def visit_Arel_Nodes_Case(o)
          visit_edge(o, "case")
          visit_edge(o, "conditions")
          visit_edge(o, "default")
        end

        def visit_edge(o, method)
          edge(method) { visit o.send(method) }
        end

        def visit(o)
          if node = @seen[o.object_id]
            @edge_stack.last.to = node
            return
          end

          node = Node.new(o.class.name, o.object_id)
          @seen[node.id] = node
          @nodes << node
          with_node node do
            super
          end
        end

        def edge(name)
          edge = Edge.new(name, @node_stack.last)
          @edge_stack.push edge
          @edges << edge
          yield
          @edge_stack.pop
        end

        def with_node(node)
          if edge = @edge_stack.last
            edge.to = node
          end

          @node_stack.push node
          yield
          @node_stack.pop
        end

        def quote(string)
          string.to_s.gsub('"', '\"')
        end

        def to_dot
          "digraph \"Arel\" {\nnode [width=0.375,height=0.25,shape=record];\n" +
            @nodes.map { |node|
              label = "<f0>#{node.name}"

              node.fields.each_with_index do |field, i|
                label += "|<f#{i + 1}>#{quote field}"
              end

              "#{node.id} [label=\"#{label}\"];"
            }.join("\n") + "\n" + @edges.map { |edge|
              "#{edge.from.id} -> #{edge.to.id} [label=\"#{edge.name}\"];"
            }.join("\n") + "\n}"
        end
    end
  end
end

dynamic_matchers.rb

# frozen_string_literal: true

module ActiveRecord
  module DynamicMatchers # :nodoc:
    private
      def respond_to_missing?(name, _)
        if self == Base
          super
        else
          match = Method.match(self, name)
          match && match.valid? || super
        end
      end

      def method_missing(name, *arguments, &block)
        match = Method.match(self, name)

        if match && match.valid?
          match.define
          send(name, *arguments, &block)
        else
          super
        end
      end

      class Method
        @matchers = []

        class << self
          attr_reader :matchers

          def match(model, name)
            klass = matchers.find { |k| k.pattern.match?(name) }
            klass.new(model, name) if klass
          end

          def pattern
            @pattern ||= /\A#{prefix}_([_a-zA-Z]\w*)#{suffix}\Z/
          end

          def prefix
            raise NotImplementedError
          end

          def suffix
            ""
          end
        end

        attr_reader :model, :name, :attribute_names

        def initialize(model, method_name)
          @model           = model
          @name            = method_name.to_s
          @attribute_names = @name.match(self.class.pattern)[1].split("_and_")
          @attribute_names.map! { |name| @model.attribute_aliases[name] || name }
        end

        def valid?
          attribute_names.all? { |name| model.columns_hash[name] || model.reflect_on_aggregation(name.to_sym) }
        end

        def define
          model.class_eval <<-CODE, __FILE__, __LINE__ + 1
            def self.#{name}(#{signature})
              #{body}
            end
          CODE
        end

        private
          def body
            "#{finder}(#{attributes_hash})"
          end

          # The parameters in the signature may have reserved Ruby words, in order
          # to prevent errors, we start each param name with `_`.
          def signature
            attribute_names.map { |name| "_#{name}" }.join(", ")
          end

          # Given that the parameters starts with `_`, the finder needs to use the
          # same parameter name.
          def attributes_hash
            "{" + attribute_names.map { |name| ":#{name} => _#{name}" }.join(",") + "}"
          end

          def finder
            raise NotImplementedError
          end
      end

      class FindBy < Method
        Method.matchers << self

        def self.prefix
          "find_by"
        end

        def finder
          "find_by"
        end
      end

      class FindByBang < Method
        Method.matchers << self

        def self.prefix
          "find_by"
        end

        def self.suffix
          "!"
        end

        def finder
          "find_by!"
        end
      end
  end
end

encryptable_record.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # This is the concern mixed in Active Record models to make them encryptable. It adds the +encrypts+
    # attribute declaration, as well as the API to encrypt and decrypt records.
    module EncryptableRecord
      extend ActiveSupport::Concern

      included do
        class_attribute :encrypted_attributes

        validate :cant_modify_encrypted_attributes_when_frozen, if: -> { has_encrypted_attributes? && ActiveRecord::Encryption.context.frozen_encryption? }
      end

      class_methods do
        # Encrypts the +name+ attribute.
        #
        # === Options
        #
        # * <tt>:key_provider</tt> - A key provider to provide encryption and decryption keys. Defaults to
        #   +ActiveRecord::Encryption.key_provider+.
        # * <tt>:key</tt> - A password to derive the key from. It's a shorthand for a +:key_provider+ that
        #   serves derivated keys. Both options can't be used at the same time.
        # * <tt>:deterministic</tt> - By default, encryption is not deterministic. It will use a random
        #   initialization vector for each encryption operation. This means that encrypting the same content
        #   with the same key twice will generate different ciphertexts. When set to +true+, it will generate the
        #   initialization vector based on the encrypted content. This means that the same content will generate
        #   the same ciphertexts. This enables querying encrypted text with Active Record. Deterministic encryption
        #   will use the oldest encryption scheme to encrypt new data by default. You can change this by setting
        #   +deterministic: { fixed: false }+. That will make it use the newest encryption scheme for encrypting new
        #   data.
        # * <tt>:downcase</tt> - When true, it converts the encrypted content to downcase automatically. This allows to
        #   effectively ignore case when querying data. Notice that the case is lost. Use +:ignore_case+ if you are interested
        #   in preserving it.
        # * <tt>:ignore_case</tt> - When true, it behaves like +:downcase+ but, it also preserves the original case in a specially
        #   designated column +original_<name>+. When reading the encrypted content, the version with the original case is
        #   served. But you can still execute queries that will ignore the case. This option can only be used when +:deterministic+
        #   is true.
        # * <tt>:context_properties</tt> - Additional properties that will override +Context+ settings when this attribute is
        #   encrypted and decrypted. E.g: +encryptor:+, +cipher:+, +message_serializer:+, etc.
        # * <tt>:previous</tt> - List of previous encryption schemes. When provided, they will be used in order when trying to read
        #   the attribute. Each entry of the list can contain the properties supported by #encrypts. Also, when deterministic
        #   encryption is used, they will be used to generate additional ciphertexts to check in the queries.
        def encrypts(*names, key_provider: nil, key: nil, deterministic: false, downcase: false, ignore_case: false, previous: [], **context_properties)
          self.encrypted_attributes ||= Set.new # not using :default because the instance would be shared across classes
          scheme = scheme_for key_provider: key_provider, key: key, deterministic: deterministic, downcase: downcase, \
              ignore_case: ignore_case, previous: previous, **context_properties

          names.each do |name|
            encrypt_attribute name, scheme
          end
        end

        # Returns the list of deterministic encryptable attributes in the model class.
        def deterministic_encrypted_attributes
          @deterministic_encrypted_attributes ||= encrypted_attributes&.find_all do |attribute_name|
            type_for_attribute(attribute_name).deterministic?
          end
        end

        # Given a attribute name, it returns the name of the source attribute when it's a preserved one.
        def source_attribute_from_preserved_attribute(attribute_name)
          attribute_name.to_s.sub(ORIGINAL_ATTRIBUTE_PREFIX, "") if /^#{ORIGINAL_ATTRIBUTE_PREFIX}/.match?(attribute_name)
        end

        private
          def scheme_for(key_provider: nil, key: nil, deterministic: false, downcase: false, ignore_case: false, previous: [], **context_properties)
            ActiveRecord::Encryption::Scheme.new(key_provider: key_provider, key: key, deterministic: deterministic,
                                                 downcase: downcase, ignore_case: ignore_case, **context_properties).tap do |scheme|
              scheme.previous_schemes = global_previous_schemes_for(scheme) +
                Array.wrap(previous).collect { |scheme_config| ActiveRecord::Encryption::Scheme.new(**scheme_config) }
            end
          end

          def global_previous_schemes_for(scheme)
            ActiveRecord::Encryption.config.previous_schemes.collect do |previous_scheme|
              scheme.merge(previous_scheme)
            end
          end

          def encrypt_attribute(name, attribute_scheme)
            encrypted_attributes << name.to_sym

            attribute name do |cast_type|
              ActiveRecord::Encryption::EncryptedAttributeType.new scheme: attribute_scheme, cast_type: cast_type
            end

            preserve_original_encrypted(name) if attribute_scheme.ignore_case?
            ActiveRecord::Encryption.encrypted_attribute_was_declared(self, name)
          end

          def preserve_original_encrypted(name)
            original_attribute_name = "#{ORIGINAL_ATTRIBUTE_PREFIX}#{name}".to_sym

            if !ActiveRecord::Encryption.config.support_unencrypted_data && !column_names.include?(original_attribute_name.to_s)
              raise Errors::Configuration, "To use :ignore_case for '#{name}' you must create an additional column named '#{original_attribute_name}'"
            end

            encrypts original_attribute_name
            override_accessors_to_preserve_original name, original_attribute_name
          end

          def override_accessors_to_preserve_original(name, original_attribute_name)
            include(Module.new do
              define_method name do
                if ((value = super()) && encrypted_attribute?(name)) || !ActiveRecord::Encryption.config.support_unencrypted_data
                  send(original_attribute_name)
                else
                  value
                end
              end

              define_method "#{name}=" do |value|
                self.send "#{original_attribute_name}=", value
                super(value)
              end
            end)
          end

          def load_schema!
            super

            add_length_validation_for_encrypted_columns if ActiveRecord::Encryption.config.validate_column_size
          end

          def add_length_validation_for_encrypted_columns
            encrypted_attributes&.each do |attribute_name|
              validate_column_size attribute_name
            end
          end

          def validate_column_size(attribute_name)
            if limit = columns_hash[attribute_name.to_s]&.limit
              validates_length_of attribute_name, maximum: limit
            end
          end
      end

      # Returns whether a given attribute is encrypted or not.
      def encrypted_attribute?(attribute_name)
        ActiveRecord::Encryption.encryptor.encrypted? ciphertext_for(attribute_name)
      end

      # Returns the ciphertext for +attribute_name+.
      def ciphertext_for(attribute_name)
        read_attribute_before_type_cast(attribute_name)
      end

      # Encrypts all the encryptable attributes and saves the changes.
      def encrypt
        encrypt_attributes if has_encrypted_attributes?
      end

      # Decrypts all the encryptable attributes and saves the changes.
      def decrypt
        decrypt_attributes if has_encrypted_attributes?
      end

      private
        ORIGINAL_ATTRIBUTE_PREFIX = "original_"

        def encrypt_attributes
          validate_encryption_allowed

          update_columns build_encrypt_attribute_assignments
        end

        def decrypt_attributes
          validate_encryption_allowed

          decrypt_attribute_assignments = build_decrypt_attribute_assignments
          ActiveRecord::Encryption.without_encryption { update_columns decrypt_attribute_assignments }
        end

        def validate_encryption_allowed
          raise ActiveRecord::Encryption::Errors::Configuration, "can't be modified because it is encrypted" if ActiveRecord::Encryption.context.frozen_encryption?
        end

        def has_encrypted_attributes?
          self.class.encrypted_attributes.present?
        end

        def build_encrypt_attribute_assignments
          Array(self.class.encrypted_attributes).index_with do |attribute_name|
            self[attribute_name]
          end
        end

        def build_decrypt_attribute_assignments
          Array(self.class.encrypted_attributes).to_h do |attribute_name|
            type = type_for_attribute(attribute_name)
            encrypted_value = ciphertext_for(attribute_name)
            new_value = type.deserialize(encrypted_value)
            [attribute_name, new_value]
          end
        end

        def cant_modify_encrypted_attributes_when_frozen
          self.class&.encrypted_attributes.each do |attribute|
            errors.add(attribute.to_sym, "can't be modified because it is encrypted") if changed_attributes.include?(attribute)
          end
        end
    end
  end
end

encrypted_attribute_type.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # An ActiveModel::Type::Value that encrypts/decrypts strings of text.
    #
    # This is the central piece that connects the encryption system with +encrypts+ declarations in the
    # model classes. Whenever you declare an attribute as encrypted, it configures an +EncryptedAttributeType+
    # for that attribute.
    class EncryptedAttributeType < ::ActiveRecord::Type::Text
      include ActiveModel::Type::Helpers::Mutable

      attr_reader :scheme, :cast_type

      delegate :key_provider, :downcase?, :deterministic?, :previous_schemes, :with_context, :fixed?, to: :scheme
      delegate :accessor, to: :cast_type

      # === Options
      #
      # * <tt>:scheme</tt> - A +Scheme+ with the encryption properties for this attribute.
      # * <tt>:cast_type</tt> - A type that will be used to serialize (before encrypting) and deserialize
      #   (after decrypting). ActiveModel::Type::String by default.
      def initialize(scheme:, cast_type: ActiveModel::Type::String.new, previous_type: false)
        super()
        @scheme = scheme
        @cast_type = cast_type
        @previous_type = previous_type
      end

      def deserialize(value)
        cast_type.deserialize decrypt(value)
      end

      def serialize(value)
        if serialize_with_oldest?
          serialize_with_oldest(value)
        else
          serialize_with_current(value)
        end
      end

      def changed_in_place?(raw_old_value, new_value)
        old_value = raw_old_value.nil? ? nil : deserialize(raw_old_value)
        old_value != new_value
      end

      def previous_types # :nodoc:
        @previous_types ||= {} # Memoizing on support_unencrypted_data so that we can tweak it during tests
        @previous_types[support_unencrypted_data?] ||= build_previous_types_for(previous_schemes_including_clean_text)
      end

      private
        def previous_schemes_including_clean_text
          previous_schemes.including((clean_text_scheme if support_unencrypted_data?)).compact
        end

        def previous_types_without_clean_text
          @previous_types_without_clean_text ||= build_previous_types_for(previous_schemes)
        end

        def build_previous_types_for(schemes)
          schemes.collect do |scheme|
            EncryptedAttributeType.new(scheme: scheme, previous_type: true)
          end
        end

        def previous_type?
          @previous_type
        end

        def decrypt(value)
          with_context do
            encryptor.decrypt(value, **decryption_options) unless value.nil?
          end
        rescue ActiveRecord::Encryption::Errors::Base => error
          if previous_types_without_clean_text.blank?
            handle_deserialize_error(error, value)
          else
            try_to_deserialize_with_previous_encrypted_types(value)
          end
        end

        def try_to_deserialize_with_previous_encrypted_types(value)
          previous_types.each.with_index do |type, index|
            break type.deserialize(value)
          rescue ActiveRecord::Encryption::Errors::Base => error
            handle_deserialize_error(error, value) if index == previous_types.length - 1
          end
        end

        def handle_deserialize_error(error, value)
          if error.is_a?(Errors::Decryption) && support_unencrypted_data?
            value
          else
            raise error
          end
        end

        def serialize_with_oldest?
          @serialize_with_oldest ||= fixed? && previous_types_without_clean_text.present?
        end

        def serialize_with_oldest(value)
          previous_types.first.serialize(value)
        end

        def serialize_with_current(value)
          casted_value = cast_type.serialize(value)
          casted_value = casted_value&.downcase if downcase?
          encrypt(casted_value.to_s) unless casted_value.nil?
        end

        def encrypt(value)
          with_context do
            encryptor.encrypt(value, **encryption_options)
          end
        end

        def encryptor
          ActiveRecord::Encryption.encryptor
        end

        def support_unencrypted_data?
          ActiveRecord::Encryption.config.support_unencrypted_data && !previous_type?
        end

        def encryption_options
          @encryption_options ||= { key_provider: key_provider, cipher_options: { deterministic: deterministic? } }.compact
        end

        def decryption_options
          @decryption_options ||= { key_provider: key_provider }.compact
        end

        def clean_text_scheme
          @clean_text_scheme ||= ActiveRecord::Encryption::Scheme.new(downcase: downcase?, encryptor: ActiveRecord::Encryption::NullEncryptor.new)
        end
    end
  end
end

encrypted_fixtures.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    module EncryptedFixtures
      def initialize(fixture, model_class)
        @clean_values = {}
        encrypt_fixture_data(fixture, model_class)
        process_preserved_original_columns(fixture, model_class)
        super
      end

      private
        def encrypt_fixture_data(fixture, model_class)
          model_class&.encrypted_attributes&.each do |attribute_name|
            if clean_value = fixture[attribute_name.to_s]
              @clean_values[attribute_name.to_s] = clean_value

              type = model_class.type_for_attribute(attribute_name)
              encrypted_value = type.serialize(clean_value)
              fixture[attribute_name.to_s] = encrypted_value
            end
          end
        end

        def process_preserved_original_columns(fixture, model_class)
          model_class&.encrypted_attributes&.each do |attribute_name|
            if source_attribute_name = model_class.source_attribute_from_preserved_attribute(attribute_name)
              clean_value = @clean_values[source_attribute_name.to_s]
              type = model_class.type_for_attribute(attribute_name)
              encrypted_value = type.serialize(clean_value)
              fixture[attribute_name.to_s] = encrypted_value
            end
          end
        end
    end
  end
end

encrypting_only_encryptor.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # An encryptor that can encrypt data but can't decrypt it.
    class EncryptingOnlyEncryptor < Encryptor
      def decrypt(encrypted_text, key_provider: nil, cipher_options: {})
        encrypted_text
      end
    end
  end
end

encryption.rb

# frozen_string_literal: true

require "active_support/core_ext/module"
require "active_support/core_ext/array"

module ActiveRecord
  module Encryption
    extend ActiveSupport::Autoload

    eager_autoload do
      autoload :Cipher
      autoload :Config
      autoload :Configurable
      autoload :Context
      autoload :Contexts
      autoload :DerivedSecretKeyProvider
      autoload :EncryptableRecord
      autoload :EncryptedAttributeType
      autoload :EncryptedFixtures
      autoload :EncryptingOnlyEncryptor
      autoload :DeterministicKeyProvider
      autoload :Encryptor
      autoload :EnvelopeEncryptionKeyProvider
      autoload :Errors
      autoload :ExtendedDeterministicQueries
      autoload :ExtendedDeterministicUniquenessValidator
      autoload :Key
      autoload :KeyGenerator
      autoload :KeyProvider
      autoload :Message
      autoload :MessageSerializer
      autoload :NullEncryptor
      autoload :Properties
      autoload :ReadOnlyNullEncryptor
      autoload :Scheme
    end

    class Cipher
      extend ActiveSupport::Autoload

      eager_autoload do
        autoload :Aes256Gcm
      end
    end

    include Configurable
    include Contexts

    def self.eager_load!
      super

      Cipher.eager_load!
    end
  end
end

encryptor.rb

# frozen_string_literal: true

require "openssl"
require "zlib"
require "active_support/core_ext/numeric"

module ActiveRecord
  module Encryption
    # An encryptor exposes the encryption API that ActiveRecord::Encryption::EncryptedAttributeType
    # uses for encrypting and decrypting attribute values.
    #
    # It interacts with a KeyProvider for getting the keys, and delegate to
    # ActiveRecord::Encryption::Cipher the actual encryption algorithm.
    class Encryptor
      # Encrypts +clean_text+ and returns the encrypted result
      #
      # Internally, it will:
      #
      # 1. Create a new ActiveRecord::Encryption::Message
      # 2. Compress and encrypt +clean_text+ as the message payload
      # 3. Serialize it with +ActiveRecord::Encryption.message_serializer+ (+ActiveRecord::Encryption::SafeMarshal+
      #    by default)
      # 4. Encode the result with Base 64
      #
      # === Options
      #
      # [:key_provider]
      #   Key provider to use for the encryption operation. It will default to
      #   +ActiveRecord::Encryption.key_provider+ when not provided.
      #
      # [:cipher_options]
      #   Cipher-specific options that will be passed to the Cipher configured in
      #   +ActiveRecord::Encryption.cipher+
      def encrypt(clear_text, key_provider: default_key_provider, cipher_options: {})
        clear_text = force_encoding_if_needed(clear_text) if cipher_options[:deterministic]

        validate_payload_type(clear_text)
        serialize_message build_encrypted_message(clear_text, key_provider: key_provider, cipher_options: cipher_options)
      end

      # Decrypts a +clean_text+ and returns the result as clean text
      #
      # === Options
      #
      # [:key_provider]
      #   Key provider to use for the encryption operation. It will default to
      #   +ActiveRecord::Encryption.key_provider+ when not provided
      #
      # [:cipher_options]
      #   Cipher-specific options that will be passed to the Cipher configured in
      #   +ActiveRecord::Encryption.cipher+
      def decrypt(encrypted_text, key_provider: default_key_provider, cipher_options: {})
        message = deserialize_message(encrypted_text)
        keys = key_provider.decryption_keys(message)
        raise Errors::Decryption unless keys.present?
        uncompress_if_needed(cipher.decrypt(message, key: keys.collect(&:secret), **cipher_options), message.headers.compressed)
      rescue *(ENCODING_ERRORS + DECRYPT_ERRORS)
        raise Errors::Decryption
      end

      # Returns whether the text is encrypted or not
      def encrypted?(text)
        deserialize_message(text)
        true
      rescue Errors::Encoding, *DECRYPT_ERRORS
        false
      end

      private
        DECRYPT_ERRORS = [OpenSSL::Cipher::CipherError, Errors::EncryptedContentIntegrity, Errors::Decryption]
        ENCODING_ERRORS = [EncodingError, Errors::Encoding]
        THRESHOLD_TO_JUSTIFY_COMPRESSION = 140.bytes

        def default_key_provider
          ActiveRecord::Encryption.key_provider
        end

        def validate_payload_type(clear_text)
          unless clear_text.is_a?(String)
            raise ActiveRecord::Encryption::Errors::ForbiddenClass, "The encryptor can only encrypt string values (#{clear_text.class})"
          end
        end

        def cipher
          ActiveRecord::Encryption.cipher
        end

        def build_encrypted_message(clear_text, key_provider:, cipher_options:)
          key = key_provider.encryption_key

          clear_text, was_compressed = compress_if_worth_it(clear_text)
          cipher.encrypt(clear_text, key: key.secret, **cipher_options).tap do |message|
            message.headers.add(key.public_tags)
            message.headers.compressed = true if was_compressed
          end
        end

        def serialize_message(message)
          serializer.dump(message)
        end

        def deserialize_message(message)
          raise Errors::Encoding unless message.is_a?(String)
          serializer.load message
        rescue ArgumentError, TypeError, Errors::ForbiddenClass
          raise Errors::Encoding
        end

        def serializer
          ActiveRecord::Encryption.message_serializer
        end

        # Under certain threshold, ZIP compression is actually worse that not compressing
        def compress_if_worth_it(string)
          if string.bytesize > THRESHOLD_TO_JUSTIFY_COMPRESSION
            [compress(string), true]
          else
            [string, false]
          end
        end

        def compress(data)
          Zlib::Deflate.deflate(data).tap do |compressed_data|
            compressed_data.force_encoding(data.encoding)
          end
        end

        def uncompress_if_needed(data, compressed)
          if compressed
            uncompress(data)
          else
            data
          end
        end

        def uncompress(data)
          Zlib::Inflate.inflate(data).tap do |uncompressed_data|
            uncompressed_data.force_encoding(data.encoding)
          end
        end

        def force_encoding_if_needed(value)
          if forced_encoding_for_deterministic_encryption && value && value.encoding != forced_encoding_for_deterministic_encryption
            value.encode(forced_encoding_for_deterministic_encryption, invalid: :replace, undef: :replace)
          else
            value
          end
        end

        def forced_encoding_for_deterministic_encryption
          ActiveRecord::Encryption.config.forced_encoding_for_deterministic_encryption
        end
    end
  end
end

enum.rb

# frozen_string_literal: true

require "active_support/core_ext/hash/slice"
require "active_support/core_ext/object/deep_dup"

module ActiveRecord
  # Declare an enum attribute where the values map to integers in the database,
  # but can be queried by name. Example:
  #
  #   class Conversation < ActiveRecord::Base
  #     enum :status, [ :active, :archived ]
  #   end
  #
  #   # conversation.update! status: 0
  #   conversation.active!
  #   conversation.active? # => true
  #   conversation.status  # => "active"
  #
  #   # conversation.update! status: 1
  #   conversation.archived!
  #   conversation.archived? # => true
  #   conversation.status    # => "archived"
  #
  #   # conversation.status = 1
  #   conversation.status = "archived"
  #
  #   conversation.status = nil
  #   conversation.status.nil? # => true
  #   conversation.status      # => nil
  #
  # Scopes based on the allowed values of the enum field will be provided
  # as well. With the above example:
  #
  #   Conversation.active
  #   Conversation.not_active
  #   Conversation.archived
  #   Conversation.not_archived
  #
  # Of course, you can also query them directly if the scopes don't fit your
  # needs:
  #
  #   Conversation.where(status: [:active, :archived])
  #   Conversation.where.not(status: :active)
  #
  # Defining scopes can be disabled by setting +:scopes+ to +false+.
  #
  #   class Conversation < ActiveRecord::Base
  #     enum :status, [ :active, :archived ], scopes: false
  #   end
  #
  # You can set the default enum value by setting +:default+, like:
  #
  #   class Conversation < ActiveRecord::Base
  #     enum :status, [ :active, :archived ], default: :active
  #   end
  #
  #   conversation = Conversation.new
  #   conversation.status # => "active"
  #
  # It's possible to explicitly map the relation between attribute and
  # database integer with a hash:
  #
  #   class Conversation < ActiveRecord::Base
  #     enum :status, active: 0, archived: 1
  #   end
  #
  # Finally it's also possible to use a string column to persist the enumerated value.
  # Note that this will likely lead to slower database queries:
  #
  #   class Conversation < ActiveRecord::Base
  #     enum :status, active: "active", archived: "archived"
  #   end
  #
  # Note that when an array is used, the implicit mapping from the values to database
  # integers is derived from the order the values appear in the array. In the example,
  # <tt>:active</tt> is mapped to +0+ as it's the first element, and <tt>:archived</tt>
  # is mapped to +1+. In general, the +i+-th element is mapped to <tt>i-1</tt> in the
  # database.
  #
  # Therefore, once a value is added to the enum array, its position in the array must
  # be maintained, and new values should only be added to the end of the array. To
  # remove unused values, the explicit hash syntax should be used.
  #
  # In rare circumstances you might need to access the mapping directly.
  # The mappings are exposed through a class method with the pluralized attribute
  # name, which return the mapping in a ActiveSupport::HashWithIndifferentAccess :
  #
  #   Conversation.statuses[:active]    # => 0
  #   Conversation.statuses["archived"] # => 1
  #
  # Use that class method when you need to know the ordinal value of an enum.
  # For example, you can use that when manually building SQL strings:
  #
  #   Conversation.where("status <> ?", Conversation.statuses[:archived])
  #
  # You can use the +:prefix+ or +:suffix+ options when you need to define
  # multiple enums with same values. If the passed value is +true+, the methods
  # are prefixed/suffixed with the name of the enum. It is also possible to
  # supply a custom value:
  #
  #   class Conversation < ActiveRecord::Base
  #     enum :status, [ :active, :archived ], suffix: true
  #     enum :comments_status, [ :active, :inactive ], prefix: :comments
  #   end
  #
  # With the above example, the bang and predicate methods along with the
  # associated scopes are now prefixed and/or suffixed accordingly:
  #
  #   conversation.active_status!
  #   conversation.archived_status? # => false
  #
  #   conversation.comments_inactive!
  #   conversation.comments_active? # => false
  module Enum
    def self.extended(base) # :nodoc:
      base.class_attribute(:defined_enums, instance_writer: false, default: {})
    end

    def inherited(base) # :nodoc:
      base.defined_enums = defined_enums.deep_dup
      super
    end

    class EnumType < Type::Value # :nodoc:
      delegate :type, to: :subtype

      def initialize(name, mapping, subtype)
        @name = name
        @mapping = mapping
        @subtype = subtype
      end

      def cast(value)
        if mapping.has_key?(value)
          value.to_s
        elsif mapping.has_value?(value)
          mapping.key(value)
        else
          value.presence
        end
      end

      def deserialize(value)
        mapping.key(subtype.deserialize(value))
      end

      def serialize(value)
        subtype.serialize(mapping.fetch(value, value))
      end

      def serializable?(value, &block)
        subtype.serializable?(mapping.fetch(value, value), &block)
      end

      def assert_valid_value(value)
        unless value.blank? || mapping.has_key?(value) || mapping.has_value?(value)
          raise ArgumentError, "'#{value}' is not a valid #{name}"
        end
      end

      attr_reader :subtype

      private
        attr_reader :name, :mapping
    end

    def enum(name = nil, values = nil, **options)
      if name
        values, options = options, {} unless values
        return _enum(name, values, **options)
      end

      definitions = options.slice!(:_prefix, :_suffix, :_scopes, :_default)
      options.transform_keys! { |key| :"#{key[1..-1]}" }

      definitions.each { |name, values| _enum(name, values, **options) }
    end

    private
      def _enum(name, values, prefix: nil, suffix: nil, scopes: true, **options)
        assert_valid_enum_definition_values(values)
        # statuses = { }
        enum_values = ActiveSupport::HashWithIndifferentAccess.new
        name = name.to_s

        # def self.statuses() statuses end
        detect_enum_conflict!(name, name.pluralize, true)
        singleton_class.define_method(name.pluralize) { enum_values }
        defined_enums[name] = enum_values

        detect_enum_conflict!(name, name)
        detect_enum_conflict!(name, "#{name}=")

        attribute(name, **options) do |subtype|
          subtype = subtype.subtype if EnumType === subtype
          EnumType.new(name, enum_values, subtype)
        end

        value_method_names = []
        _enum_methods_module.module_eval do
          prefix = if prefix
            prefix == true ? "#{name}_" : "#{prefix}_"
          end

          suffix = if suffix
            suffix == true ? "_#{name}" : "_#{suffix}"
          end

          pairs = values.respond_to?(:each_pair) ? values.each_pair : values.each_with_index
          pairs.each do |label, value|
            enum_values[label] = value
            label = label.to_s

            value_method_name = "#{prefix}#{label}#{suffix}"
            value_method_names << value_method_name
            define_enum_methods(name, value_method_name, value, scopes)

            method_friendly_label = label.gsub(/[\W&&[:ascii:]]+/, "_")
            value_method_alias = "#{prefix}#{method_friendly_label}#{suffix}"

            if value_method_alias != value_method_name && !value_method_names.include?(value_method_alias)
              value_method_names << value_method_alias
              define_enum_methods(name, value_method_alias, value, scopes)
            end
          end
        end
        detect_negative_enum_conditions!(value_method_names) if scopes
        enum_values.freeze
      end

      class EnumMethods < Module # :nodoc:
        def initialize(klass)
          @klass = klass
        end

        private
          attr_reader :klass

          def define_enum_methods(name, value_method_name, value, scopes)
            # def active?() status_for_database == 0 end
            klass.send(:detect_enum_conflict!, name, "#{value_method_name}?")
            define_method("#{value_method_name}?") { public_send(:"#{name}_for_database") == value }

            # def active!() update!(status: 0) end
            klass.send(:detect_enum_conflict!, name, "#{value_method_name}!")
            define_method("#{value_method_name}!") { update!(name => value) }

            # scope :active, -> { where(status: 0) }
            # scope :not_active, -> { where.not(status: 0) }
            if scopes
              klass.send(:detect_enum_conflict!, name, value_method_name, true)
              klass.scope value_method_name, -> { where(name => value) }

              klass.send(:detect_enum_conflict!, name, "not_#{value_method_name}", true)
              klass.scope "not_#{value_method_name}", -> { where.not(name => value) }
            end
          end
      end
      private_constant :EnumMethods

      def _enum_methods_module
        @_enum_methods_module ||= begin
          mod = EnumMethods.new(self)
          include mod
          mod
        end
      end

      def assert_valid_enum_definition_values(values)
        case values
        when Hash
          if values.empty?
            raise ArgumentError, "Enum values #{values} must not be empty."
          end

          if values.keys.any?(&:blank?)
            raise ArgumentError, "Enum values #{values} must not contain a blank name."
          end
        when Array
          if values.empty?
            raise ArgumentError, "Enum values #{values} must not be empty."
          end

          unless values.all?(Symbol) || values.all?(String)
            raise ArgumentError, "Enum values #{values} must only contain symbols or strings."
          end

          if values.any?(&:blank?)
            raise ArgumentError, "Enum values #{values} must not contain a blank name."
          end
        else
          raise ArgumentError, "Enum values #{values} must be either a non-empty hash or an array."
        end
      end

      ENUM_CONFLICT_MESSAGE = \
        "You tried to define an enum named \"%{enum}\" on the model \"%{klass}\", but " \
        "this will generate a %{type} method \"%{method}\", which is already defined " \
        "by %{source}."
      private_constant :ENUM_CONFLICT_MESSAGE

      def detect_enum_conflict!(enum_name, method_name, klass_method = false)
        if klass_method && dangerous_class_method?(method_name)
          raise_conflict_error(enum_name, method_name, type: "class")
        elsif klass_method && method_defined_within?(method_name, Relation)
          raise_conflict_error(enum_name, method_name, type: "class", source: Relation.name)
        elsif !klass_method && dangerous_attribute_method?(method_name)
          raise_conflict_error(enum_name, method_name)
        elsif !klass_method && method_defined_within?(method_name, _enum_methods_module, Module)
          raise_conflict_error(enum_name, method_name, source: "another enum")
        end
      end

      def raise_conflict_error(enum_name, method_name, type: "instance", source: "Active Record")
        raise ArgumentError, ENUM_CONFLICT_MESSAGE % {
          enum: enum_name,
          klass: name,
          type: type,
          method: method_name,
          source: source
        }
      end

      def detect_negative_enum_conditions!(method_names)
        return unless logger

        method_names.select { |m| m.start_with?("not_") }.each do |potential_not|
          inverted_form = potential_not.sub("not_", "")
          if method_names.include?(inverted_form)
            logger.warn "Enum element '#{potential_not}' in #{self.name} uses the prefix 'not_'." \
              " This has caused a conflict with auto generated negative scopes." \
              " Avoid using enum elements starting with 'not' where the positive form is also an element."
          end
        end
      end
  end
end

envelope_encryption_key_provider.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # Implements a simple envelope encryption approach where:
    #
    # * It generates a random data-encryption key for each encryption operation.
    # * It stores the generated key along with the encrypted payload. It encrypts this key
    #   with the master key provided in the +active_record_encryption.primary_key+ credential.
    #
    # This provider can work with multiple master keys. It will use the last one for encrypting.
    #
    # When +config.active_record.encryption.store_key_references+ is true, it will also store a reference to
    # the specific master key that was used to encrypt the data-encryption key. When not set,
    # it will try all the configured master keys looking for the right one, in order to
    # return the right decryption key.
    class EnvelopeEncryptionKeyProvider
      def encryption_key
        random_secret = generate_random_secret
        ActiveRecord::Encryption::Key.new(random_secret).tap do |key|
          key.public_tags.encrypted_data_key = encrypt_data_key(random_secret)
          key.public_tags.encrypted_data_key_id = active_primary_key.id if ActiveRecord::Encryption.config.store_key_references
        end
      end

      def decryption_keys(encrypted_message)
        secret = decrypt_data_key(encrypted_message)
        secret ? [ActiveRecord::Encryption::Key.new(secret)] : []
      end

      def active_primary_key
        @active_primary_key ||= primary_key_provider.encryption_key
      end

      private
        def encrypt_data_key(random_secret)
          ActiveRecord::Encryption.cipher.encrypt(random_secret, key: active_primary_key.secret)
        end

        def decrypt_data_key(encrypted_message)
          encrypted_data_key = encrypted_message.headers.encrypted_data_key
          key = primary_key_provider.decryption_keys(encrypted_message)&.collect(&:secret)
          ActiveRecord::Encryption.cipher.decrypt encrypted_data_key, key: key if key
        end

        def primary_key_provider
          @primary_key_provider ||= DerivedSecretKeyProvider.new(ActiveRecord::Encryption.config.primary_key)
        end

        def generate_random_secret
          ActiveRecord::Encryption.key_generator.generate_random_key
        end
    end
  end
end

equality.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Equality < Arel::Nodes::Binary
      include FetchAttribute

      def equality?; true; end

      def invert
        Arel::Nodes::NotEqual.new(left, right)
      end
    end
  end
end

errors.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  class ArelError < StandardError
  end

  class EmptyJoinError < ArelError
  end
end

explain.rb

# frozen_string_literal: true

require "active_record/explain_registry"

module ActiveRecord
  module Explain
    # Executes the block with the collect flag enabled. Queries are collected
    # asynchronously by the subscriber and returned.
    def collecting_queries_for_explain # :nodoc:
      ExplainRegistry.collect = true
      yield
      ExplainRegistry.queries
    ensure
      ExplainRegistry.reset
    end

    # Makes the adapter execute EXPLAIN for the tuples of queries and bindings.
    # Returns a formatted string ready to be logged.
    def exec_explain(queries) # :nodoc:
      str = queries.map do |sql, binds|
        msg = +"EXPLAIN for: #{sql}"
        unless binds.empty?
          msg << " "
          msg << binds.map { |attr| render_bind(attr) }.inspect
        end
        msg << "\n"
        msg << connection.explain(sql, binds)
      end.join("\n")

      # Overriding inspect to be more human readable, especially in the console.
      def str.inspect
        self
      end

      str
    end

    private
      def render_bind(attr)
        if ActiveModel::Attribute === attr
          value = if attr.type.binary? && attr.value
            "<#{attr.value_for_database.to_s.bytesize} bytes of binary data>"
          else
            connection.type_cast(attr.value_for_database)
          end
        else
          value = connection.type_cast(attr)
          attr  = nil
        end

        [attr&.name, value]
      end
  end
end

explain_pretty_printer.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module SQLite3
      class ExplainPrettyPrinter # :nodoc:
        # Pretty prints the result of an EXPLAIN QUERY PLAN in a way that resembles
        # the output of the SQLite shell:
        #
        #   0|0|0|SEARCH TABLE users USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
        #   0|1|1|SCAN TABLE posts (~100000 rows)
        #
        def pp(result)
          result.rows.map do |row|
            row.join("|")
          end.join("\n") + "\n"
        end
      end
    end
  end
end

explain_registry.rb

# frozen_string_literal: true

require "active_support/core_ext/module/delegation"

module ActiveRecord
  # This is a thread locals registry for EXPLAIN. For example
  #
  #   ActiveRecord::ExplainRegistry.queries
  #
  # returns the collected queries local to the current thread.
  class ExplainRegistry # :nodoc:
    class << self
      delegate :reset, :collect, :collect=, :collect?, :queries, to: :instance

      private
        def instance
          ActiveSupport::IsolatedExecutionState[:active_record_explain_registry] ||= new
        end
    end

    attr_accessor :collect
    attr_reader :queries

    def initialize
      reset
    end

    def collect?
      @collect
    end

    def reset
      @collect = false
      @queries = []
    end
  end
end

explain_subscriber.rb

# frozen_string_literal: true

require "active_support/notifications"
require "active_record/explain_registry"

module ActiveRecord
  class ExplainSubscriber # :nodoc:
    def start(name, id, payload)
      # unused
    end

    def finish(name, id, payload)
      if ExplainRegistry.collect? && !ignore_payload?(payload)
        ExplainRegistry.queries << payload.values_at(:sql, :binds)
      end
    end

    # SCHEMA queries cannot be EXPLAINed, also we do not want to run EXPLAIN on
    # our own EXPLAINs no matter how loopingly beautiful that would be.
    #
    # On the other hand, we want to monitor the performance of our real database
    # queries, not the performance of the access to the query cache.
    IGNORED_PAYLOADS = %w(SCHEMA EXPLAIN)
    EXPLAINED_SQLS = /\A\s*(\/\*.*\*\/)?\s*(with|select|update|delete|insert)\b/i
    def ignore_payload?(payload)
      payload[:exception] ||
        payload[:cached] ||
        IGNORED_PAYLOADS.include?(payload[:name]) ||
        !payload[:sql].match?(EXPLAINED_SQLS)
    end

    ActiveSupport::Notifications.subscribe("sql.active_record", new)
  end
end

expressions.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Expressions
    def count(distinct = false)
      Nodes::Count.new [self], distinct
    end

    def sum
      Nodes::Sum.new [self]
    end

    def maximum
      Nodes::Max.new [self]
    end

    def minimum
      Nodes::Min.new [self]
    end

    def average
      Nodes::Avg.new [self]
    end

    def extract(field)
      Nodes::Extract.new [self], field
    end
  end
end

extended_deterministic_queries.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # Automatically expand encrypted arguments to support querying both encrypted and unencrypted data
    #
    # Active Record \Encryption supports querying the db using deterministic attributes. For example:
    #
    #   Contact.find_by(email_address: "jorge@hey.com")
    #
    # The value "jorge@hey.com" will get encrypted automatically to perform the query. But there is
    # a problem while the data is being encrypted. This won't work. During that time, you need these
    # queries to be:
    #
    #   Contact.find_by(email_address: [ "jorge@hey.com", "<encrypted jorge@hey.com>" ])
    #
    # This patches ActiveRecord to support this automatically. It addresses both:
    #
    # * ActiveRecord::Base - Used in <tt>Contact.find_by_email_address(...)</tt>
    # * ActiveRecord::Relation - Used in <tt>Contact.internal.find_by_email_address(...)</tt>
    #
    # ActiveRecord::Base relies on ActiveRecord::Relation (ActiveRecord::QueryMethods) but it does
    # some prepared statements caching. That's why we need to intercept +ActiveRecord::Base+ as soon
    # as it's invoked (so that the proper prepared statement is cached).
    #
    # When modifying this file run performance tests in +test/performance/extended_deterministic_queries_performance_test.rb+ to
    #   make sure performance overhead is acceptable.
    #
    # We will extend this to support previous "encryption context" versions in future iterations
    #
    # @TODO Experimental. Support for every kind of query is pending
    # @TODO It should not patch anything if not needed (no previous schemes or no support for previous encryption schemes)
    module ExtendedDeterministicQueries
      def self.install_support
        ActiveRecord::Relation.prepend(RelationQueries)
        ActiveRecord::Base.include(CoreQueries)
        ActiveRecord::Encryption::EncryptedAttributeType.prepend(ExtendedEncryptableType)
        Arel::Nodes::HomogeneousIn.prepend(InWithAdditionalValues)
      end

      module EncryptedQueryArgumentProcessor
        extend ActiveSupport::Concern

        private
          def process_encrypted_query_arguments(args, check_for_additional_values)
            if args.is_a?(Array) && (options = args.first).is_a?(Hash)
              self.deterministic_encrypted_attributes&.each do |attribute_name|
                type = type_for_attribute(attribute_name)
                if !type.previous_types.empty? && value = options[attribute_name]
                  options[attribute_name] = process_encrypted_query_argument(value, check_for_additional_values, type)
                end
              end
            end
          end

          def process_encrypted_query_argument(value, check_for_additional_values, type)
            return value if check_for_additional_values && value.is_a?(Array) && value.last.is_a?(AdditionalValue)

            case value
            when String, Array
              list = Array(value)
              list + list.flat_map do |each_value|
                if check_for_additional_values && each_value.is_a?(AdditionalValue)
                  each_value
                else
                  additional_values_for(each_value, type)
                end
              end
            else
              value
            end
          end

          def additional_values_for(value, type)
            type.previous_types.collect do |additional_type|
              AdditionalValue.new(value, additional_type)
            end
          end
      end

      module RelationQueries
        include EncryptedQueryArgumentProcessor

        def where(*args)
          process_encrypted_query_arguments_if_needed(args)
          super
        end

        def exists?(*args)
          process_encrypted_query_arguments_if_needed(args)
          super
        end

        def find_or_create_by(attributes, &block)
          find_by(attributes.dup) || create(attributes, &block)
        end

        def find_or_create_by!(attributes, &block)
          find_by(attributes.dup) || create!(attributes, &block)
        end

        private
          def process_encrypted_query_arguments_if_needed(args)
            process_encrypted_query_arguments(args, true) unless self.deterministic_encrypted_attributes&.empty?
          end
      end

      module CoreQueries
        extend ActiveSupport::Concern

        class_methods do
          include EncryptedQueryArgumentProcessor

          def find_by(*args)
            process_encrypted_query_arguments(args, false) unless self.deterministic_encrypted_attributes&.empty?
            super
          end
        end
      end

      class AdditionalValue
        attr_reader :value, :type

        def initialize(value, type)
          @type = type
          @value = process(value)
        end

        private
          def process(value)
            type.serialize(value)
          end
      end

      module ExtendedEncryptableType
        def serialize(data)
          if data.is_a?(AdditionalValue)
            data.value
          else
            super
          end
        end
      end

      module InWithAdditionalValues
        def proc_for_binds
          -> value { ActiveModel::Attribute.with_cast_value(attribute.name, value, encryption_aware_type_caster) }
        end

        def encryption_aware_type_caster
          if attribute.type_caster.is_a?(ActiveRecord::Encryption::EncryptedAttributeType)
            attribute.type_caster.cast_type
          else
            attribute.type_caster
          end
        end
      end
    end
  end
end

extended_deterministic_uniqueness_validator.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    module ExtendedDeterministicUniquenessValidator
      def self.install_support
        ActiveRecord::Validations::UniquenessValidator.prepend(EncryptedUniquenessValidator)
      end

      module EncryptedUniquenessValidator
        def validate_each(record, attribute, value)
          super(record, attribute, value)

          klass = record.class
          klass.deterministic_encrypted_attributes&.each do |attribute_name|
            encrypted_type = klass.type_for_attribute(attribute_name)
            [ encrypted_type, *encrypted_type.previous_types ].each do |type|
              encrypted_value = type.serialize(value)
              ActiveRecord::Encryption.without_encryption do
                super(record, attribute, encrypted_value)
              end
            end
          end
        end
      end
    end
  end
end

extract.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Extract < Arel::Nodes::Unary
      attr_accessor :field

      def initialize(expr, field)
        super(expr)
        @field = field
      end

      def hash
        super ^ @field.hash
      end

      def eql?(other)
        super &&
          self.field == other.field
      end
      alias :== :eql?
    end
  end
end

factory_methods.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  ###
  # Methods for creating various nodes
  module FactoryMethods
    def create_true
      Arel::Nodes::True.new
    end

    def create_false
      Arel::Nodes::False.new
    end

    def create_table_alias(relation, name)
      Nodes::TableAlias.new(relation, name)
    end

    def create_join(to, constraint = nil, klass = Nodes::InnerJoin)
      klass.new(to, constraint)
    end

    def create_string_join(to)
      create_join to, nil, Nodes::StringJoin
    end

    def create_and(clauses)
      Nodes::And.new clauses
    end

    def create_on(expr)
      Nodes::On.new expr
    end

    def grouping(expr)
      Nodes::Grouping.new expr
    end

    ###
    # Create a LOWER() function
    def lower(column)
      Nodes::NamedFunction.new "LOWER", [Nodes.build_quoted(column)]
    end

    def coalesce(*exprs)
      Nodes::NamedFunction.new "COALESCE", exprs
    end
  end
end

false.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class False < Arel::Nodes::NodeExpression
      def hash
        self.class.hash
      end

      def eql?(other)
        self.class == other.class
      end
      alias :== :eql?
    end
  end
end

file.rb

# frozen_string_literal: true

require "active_support/configuration_file"

module ActiveRecord
  class FixtureSet
    class File # :nodoc:
      include Enumerable

      ##
      # Open a fixture file named +file+.  When called with a block, the block
      # is called with the filehandle and the filehandle is automatically closed
      # when the block finishes.
      def self.open(file)
        x = new file
        block_given? ? yield(x) : x
      end

      def initialize(file)
        @file = file
      end

      def each(&block)
        rows.each(&block)
      end

      def model_class
        config_row["model_class"]
      end

      def ignored_fixtures
        config_row["ignore"]
      end

      private
        def rows
          @rows ||= raw_rows.reject { |fixture_name, _| fixture_name == "_fixture" }
        end

        def config_row
          @config_row ||= begin
            row = raw_rows.find { |fixture_name, _| fixture_name == "_fixture" }
            if row
              validate_config_row(row.last)
            else
              { 'model_class': nil, 'ignore': nil }
            end
          end
        end

        def raw_rows
          @raw_rows ||= begin
            data = ActiveSupport::ConfigurationFile.parse(@file, context:
              ActiveRecord::FixtureSet::RenderContext.create_subclass.new.get_binding)
            data ? validate(data).to_a : []
          rescue RuntimeError => error
            raise Fixture::FormatError, error.message
          end
        end

        def validate_config_row(data)
          unless Hash === data
            raise Fixture::FormatError, "Invalid `_fixture` section: `_fixture` must be a hash: #{@file}"
          end

          begin
            data.assert_valid_keys("model_class", "ignore")
          rescue ArgumentError => error
            raise Fixture::FormatError, "Invalid `_fixture` section: #{error.message}: #{@file}"
          end

          data
        end

        # Validate our unmarshalled data.
        def validate(data)
          unless Hash === data || YAML::Omap === data
            raise Fixture::FormatError, "fixture is not a hash: #{@file}"
          end

          invalid = data.reject { |_, row| Hash === row }
          if invalid.any?
            raise Fixture::FormatError, "fixture key is not a hash: #{@file}, keys: #{invalid.keys.inspect}"
          end
          data
        end
    end
  end
end

filter.rb

# frozen_string_literal: true

module Arel
  module Nodes
    class Filter < Binary
      include Arel::WindowPredications
      include Arel::AliasPredication
    end
  end
end

filter_predications.rb

# frozen_string_literal: true

module Arel
  module FilterPredications
    def filter(expr)
      Nodes::Filter.new(self, expr)
    end
  end
end

finder_methods.rb

# frozen_string_literal: true

require "active_support/core_ext/string/filters"

module ActiveRecord
  module FinderMethods
    ONE_AS_ONE = "1 AS one"

    # Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]).
    # If one or more records cannot be found for the requested ids, then ActiveRecord::RecordNotFound will be raised.
    # If the primary key is an integer, find by id coerces its arguments by using +to_i+.
    #
    #   Person.find(1)          # returns the object for ID = 1
    #   Person.find("1")        # returns the object for ID = 1
    #   Person.find("31-sarah") # returns the object for ID = 31
    #   Person.find(1, 2, 6)    # returns an array for objects with IDs in (1, 2, 6)
    #   Person.find([7, 17])    # returns an array for objects with IDs in (7, 17)
    #   Person.find([1])        # returns an array for the object with ID = 1
    #   Person.where("administrator = 1").order("created_on DESC").find(1)
    #
    # NOTE: The returned records are in the same order as the ids you provide.
    # If you want the results to be sorted by database, you can use ActiveRecord::QueryMethods#where
    # method and provide an explicit ActiveRecord::QueryMethods#order option.
    # But ActiveRecord::QueryMethods#where method doesn't raise ActiveRecord::RecordNotFound.
    #
    # ==== Find with lock
    #
    # Example for find with a lock: Imagine two concurrent transactions:
    # each will read <tt>person.visits == 2</tt>, add 1 to it, and save, resulting
    # in two saves of <tt>person.visits = 3</tt>. By locking the row, the second
    # transaction has to wait until the first is finished; we get the
    # expected <tt>person.visits == 4</tt>.
    #
    #   Person.transaction do
    #     person = Person.lock(true).find(1)
    #     person.visits += 1
    #     person.save!
    #   end
    #
    # ==== Variations of #find
    #
    #   Person.where(name: 'Spartacus', rating: 4)
    #   # returns a chainable list (which can be empty).
    #
    #   Person.find_by(name: 'Spartacus', rating: 4)
    #   # returns the first item or nil.
    #
    #   Person.find_or_initialize_by(name: 'Spartacus', rating: 4)
    #   # returns the first item or returns a new instance (requires you call .save to persist against the database).
    #
    #   Person.find_or_create_by(name: 'Spartacus', rating: 4)
    #   # returns the first item or creates it and returns it.
    #
    # ==== Alternatives for #find
    #
    #   Person.where(name: 'Spartacus', rating: 4).exists?(conditions = :none)
    #   # returns a boolean indicating if any record with the given conditions exist.
    #
    #   Person.where(name: 'Spartacus', rating: 4).select("field1, field2, field3")
    #   # returns a chainable list of instances with only the mentioned fields.
    #
    #   Person.where(name: 'Spartacus', rating: 4).ids
    #   # returns an Array of ids.
    #
    #   Person.where(name: 'Spartacus', rating: 4).pluck(:field1, :field2)
    #   # returns an Array of the required fields.
    def find(*args)
      return super if block_given?
      find_with_ids(*args)
    end

    # Finds the first record matching the specified conditions. There
    # is no implied ordering so if order matters, you should specify it
    # yourself.
    #
    # If no record is found, returns <tt>nil</tt>.
    #
    #   Post.find_by name: 'Spartacus', rating: 4
    #   Post.find_by "published_at < ?", 2.weeks.ago
    def find_by(arg, *args)
      where(arg, *args).take
    end

    # Like #find_by, except that if no record is found, raises
    # an ActiveRecord::RecordNotFound error.
    def find_by!(arg, *args)
      where(arg, *args).take!
    end

    # Gives a record (or N records if a parameter is supplied) without any implied
    # order. The order will depend on the database implementation.
    # If an order is supplied it will be respected.
    #
    #   Person.take # returns an object fetched by SELECT * FROM people LIMIT 1
    #   Person.take(5) # returns 5 objects fetched by SELECT * FROM people LIMIT 5
    #   Person.where(["name LIKE '%?'", name]).take
    def take(limit = nil)
      limit ? find_take_with_limit(limit) : find_take
    end

    # Same as #take but raises ActiveRecord::RecordNotFound if no record
    # is found. Note that #take! accepts no arguments.
    def take!
      take || raise_record_not_found_exception!
    end

    # Finds the sole matching record. Raises ActiveRecord::RecordNotFound if no
    # record is found. Raises ActiveRecord::SoleRecordExceeded if more than one
    # record is found.
    #
    #   Product.where(["price = %?", price]).sole
    def sole
      found, undesired = first(2)

      if found.nil?
        raise_record_not_found_exception!
      elsif undesired.present?
        raise ActiveRecord::SoleRecordExceeded.new(self)
      else
        found
      end
    end

    # Finds the sole matching record. Raises ActiveRecord::RecordNotFound if no
    # record is found. Raises ActiveRecord::SoleRecordExceeded if more than one
    # record is found.
    #
    #   Product.find_sole_by(["price = %?", price])
    def find_sole_by(arg, *args)
      where(arg, *args).sole
    end

    # Find the first record (or first N records if a parameter is supplied).
    # If no order is defined it will order by primary key.
    #
    #   Person.first # returns the first object fetched by SELECT * FROM people ORDER BY people.id LIMIT 1
    #   Person.where(["user_name = ?", user_name]).first
    #   Person.where(["user_name = :u", { u: user_name }]).first
    #   Person.order("created_on DESC").offset(5).first
    #   Person.first(3) # returns the first three objects fetched by SELECT * FROM people ORDER BY people.id LIMIT 3
    #
    def first(limit = nil)
      if limit
        find_nth_with_limit(0, limit)
      else
        find_nth 0
      end
    end

    # Same as #first but raises ActiveRecord::RecordNotFound if no record
    # is found. Note that #first! accepts no arguments.
    def first!
      first || raise_record_not_found_exception!
    end

    # Find the last record (or last N records if a parameter is supplied).
    # If no order is defined it will order by primary key.
    #
    #   Person.last # returns the last object fetched by SELECT * FROM people
    #   Person.where(["user_name = ?", user_name]).last
    #   Person.order("created_on DESC").offset(5).last
    #   Person.last(3) # returns the last three objects fetched by SELECT * FROM people.
    #
    # Take note that in that last case, the results are sorted in ascending order:
    #
    #   [#<Person id:2>, #<Person id:3>, #<Person id:4>]
    #
    # and not:
    #
    #   [#<Person id:4>, #<Person id:3>, #<Person id:2>]
    def last(limit = nil)
      return find_last(limit) if loaded? || has_limit_or_offset?

      result = ordered_relation.limit(limit)
      result = result.reverse_order!

      limit ? result.reverse : result.first
    end

    # Same as #last but raises ActiveRecord::RecordNotFound if no record
    # is found. Note that #last! accepts no arguments.
    def last!
      last || raise_record_not_found_exception!
    end

    # Find the second record.
    # If no order is defined it will order by primary key.
    #
    #   Person.second # returns the second object fetched by SELECT * FROM people
    #   Person.offset(3).second # returns the second object from OFFSET 3 (which is OFFSET 4)
    #   Person.where(["user_name = :u", { u: user_name }]).second
    def second
      find_nth 1
    end

    # Same as #second but raises ActiveRecord::RecordNotFound if no record
    # is found.
    def second!
      second || raise_record_not_found_exception!
    end

    # Find the third record.
    # If no order is defined it will order by primary key.
    #
    #   Person.third # returns the third object fetched by SELECT * FROM people
    #   Person.offset(3).third # returns the third object from OFFSET 3 (which is OFFSET 5)
    #   Person.where(["user_name = :u", { u: user_name }]).third
    def third
      find_nth 2
    end

    # Same as #third but raises ActiveRecord::RecordNotFound if no record
    # is found.
    def third!
      third || raise_record_not_found_exception!
    end

    # Find the fourth record.
    # If no order is defined it will order by primary key.
    #
    #   Person.fourth # returns the fourth object fetched by SELECT * FROM people
    #   Person.offset(3).fourth # returns the fourth object from OFFSET 3 (which is OFFSET 6)
    #   Person.where(["user_name = :u", { u: user_name }]).fourth
    def fourth
      find_nth 3
    end

    # Same as #fourth but raises ActiveRecord::RecordNotFound if no record
    # is found.
    def fourth!
      fourth || raise_record_not_found_exception!
    end

    # Find the fifth record.
    # If no order is defined it will order by primary key.
    #
    #   Person.fifth # returns the fifth object fetched by SELECT * FROM people
    #   Person.offset(3).fifth # returns the fifth object from OFFSET 3 (which is OFFSET 7)
    #   Person.where(["user_name = :u", { u: user_name }]).fifth
    def fifth
      find_nth 4
    end

    # Same as #fifth but raises ActiveRecord::RecordNotFound if no record
    # is found.
    def fifth!
      fifth || raise_record_not_found_exception!
    end

    # Find the forty-second record. Also known as accessing "the reddit".
    # If no order is defined it will order by primary key.
    #
    #   Person.forty_two # returns the forty-second object fetched by SELECT * FROM people
    #   Person.offset(3).forty_two # returns the forty-second object from OFFSET 3 (which is OFFSET 44)
    #   Person.where(["user_name = :u", { u: user_name }]).forty_two
    def forty_two
      find_nth 41
    end

    # Same as #forty_two but raises ActiveRecord::RecordNotFound if no record
    # is found.
    def forty_two!
      forty_two || raise_record_not_found_exception!
    end

    # Find the third-to-last record.
    # If no order is defined it will order by primary key.
    #
    #   Person.third_to_last # returns the third-to-last object fetched by SELECT * FROM people
    #   Person.offset(3).third_to_last # returns the third-to-last object from OFFSET 3
    #   Person.where(["user_name = :u", { u: user_name }]).third_to_last
    def third_to_last
      find_nth_from_last 3
    end

    # Same as #third_to_last but raises ActiveRecord::RecordNotFound if no record
    # is found.
    def third_to_last!
      third_to_last || raise_record_not_found_exception!
    end

    # Find the second-to-last record.
    # If no order is defined it will order by primary key.
    #
    #   Person.second_to_last # returns the second-to-last object fetched by SELECT * FROM people
    #   Person.offset(3).second_to_last # returns the second-to-last object from OFFSET 3
    #   Person.where(["user_name = :u", { u: user_name }]).second_to_last
    def second_to_last
      find_nth_from_last 2
    end

    # Same as #second_to_last but raises ActiveRecord::RecordNotFound if no record
    # is found.
    def second_to_last!
      second_to_last || raise_record_not_found_exception!
    end

    # Returns true if a record exists in the table that matches the +id+ or
    # conditions given, or false otherwise. The argument can take six forms:
    #
    # * Integer - Finds the record with this primary key.
    # * String - Finds the record with a primary key corresponding to this
    #   string (such as <tt>'5'</tt>).
    # * Array - Finds the record that matches these +where+-style conditions
    #   (such as <tt>['name LIKE ?', "%#{query}%"]</tt>).
    # * Hash - Finds the record that matches these +where+-style conditions
    #   (such as <tt>{name: 'David'}</tt>).
    # * +false+ - Returns always +false+.
    # * No args - Returns +false+ if the relation is empty, +true+ otherwise.
    #
    # For more information about specifying conditions as a hash or array,
    # see the Conditions section in the introduction to ActiveRecord::Base.
    #
    # Note: You can't pass in a condition as a string (like <tt>name =
    # 'Jamie'</tt>), since it would be sanitized and then queried against
    # the primary key column, like <tt>id = 'name = \'Jamie\''</tt>.
    #
    #   Person.exists?(5)
    #   Person.exists?('5')
    #   Person.exists?(['name LIKE ?', "%#{query}%"])
    #   Person.exists?(id: [1, 4, 8])
    #   Person.exists?(name: 'David')
    #   Person.exists?(false)
    #   Person.exists?
    #   Person.where(name: 'Spartacus', rating: 4).exists?
    def exists?(conditions = :none)
      if Base === conditions
        raise ArgumentError, <<-MSG.squish
          You are passing an instance of ActiveRecord::Base to `exists?`.
          Please pass the id of the object by calling `.id`.
        MSG
      end

      return false if !conditions || limit_value == 0

      if eager_loading?
        relation = apply_join_dependency(eager_loading: false)
        return relation.exists?(conditions)
      end

      relation = construct_relation_for_exists(conditions)
      return false if relation.where_clause.contradiction?

      skip_query_cache_if_necessary { connection.select_rows(relation.arel, "#{name} Exists?").size == 1 }
    end

    # Returns true if the relation contains the given record or false otherwise.
    #
    # No query is performed if the relation is loaded; the given record is
    # compared to the records in memory. If the relation is unloaded, an
    # efficient existence query is performed, as in #exists?.
    def include?(record)
      if loaded? || offset_value || limit_value || having_clause.any?
        records.include?(record)
      else
        record.is_a?(klass) && exists?(record.id)
      end
    end

    alias :member? :include?

    # This method is called whenever no records are found with either a single
    # id or multiple ids and raises an ActiveRecord::RecordNotFound exception.
    #
    # The error message is different depending on whether a single id or
    # multiple ids are provided. If multiple ids are provided, then the number
    # of results obtained should be provided in the +result_size+ argument and
    # the expected number of results should be provided in the +expected_size+
    # argument.
    def raise_record_not_found_exception!(ids = nil, result_size = nil, expected_size = nil, key = primary_key, not_found_ids = nil) # :nodoc:
      conditions = " [#{arel.where_sql(klass)}]" unless where_clause.empty?

      name = @klass.name

      if ids.nil?
        error = +"Couldn't find #{name}"
        error << " with#{conditions}" if conditions
        raise RecordNotFound.new(error, name, key)
      elsif Array.wrap(ids).size == 1
        error = "Couldn't find #{name} with '#{key}'=#{ids}#{conditions}"
        raise RecordNotFound.new(error, name, key, ids)
      else
        error = +"Couldn't find all #{name.pluralize} with '#{key}': "
        error << "(#{ids.join(", ")})#{conditions} (found #{result_size} results, but was looking for #{expected_size})."
        error << " Couldn't find #{name.pluralize(not_found_ids.size)} with #{key.to_s.pluralize(not_found_ids.size)} #{not_found_ids.join(', ')}." if not_found_ids
        raise RecordNotFound.new(error, name, key, ids)
      end
    end

    private
      def construct_relation_for_exists(conditions)
        conditions = sanitize_forbidden_attributes(conditions)

        if distinct_value && offset_value
          relation = except(:order).limit!(1)
        else
          relation = except(:select, :distinct, :order)._select!(ONE_AS_ONE).limit!(1)
        end

        case conditions
        when Array, Hash
          relation.where!(conditions) unless conditions.empty?
        else
          relation.where!(primary_key => conditions) unless conditions == :none
        end

        relation
      end

      def apply_join_dependency(eager_loading: group_values.empty?)
        join_dependency = construct_join_dependency(
          eager_load_values | includes_values, Arel::Nodes::OuterJoin
        )
        relation = except(:includes, :eager_load, :preload).joins!(join_dependency)

        if eager_loading && has_limit_or_offset? && !(
            using_limitable_reflections?(join_dependency.reflections) &&
            using_limitable_reflections?(
              construct_join_dependency(
                select_association_list(joins_values).concat(
                  select_association_list(left_outer_joins_values)
                ), nil
              ).reflections
            )
          )
          relation = skip_query_cache_if_necessary do
            klass.connection.distinct_relation_for_primary_key(relation)
          end
        end

        if block_given?
          yield relation, join_dependency
        else
          relation
        end
      end

      def using_limitable_reflections?(reflections)
        reflections.none?(&:collection?)
      end

      def find_with_ids(*ids)
        raise UnknownPrimaryKey.new(@klass) if primary_key.nil?

        expects_array = ids.first.kind_of?(Array)
        return [] if expects_array && ids.first.empty?

        ids = ids.flatten.compact.uniq

        model_name = @klass.name

        case ids.size
        when 0
          error_message = "Couldn't find #{model_name} without an ID"
          raise RecordNotFound.new(error_message, model_name, primary_key)
        when 1
          result = find_one(ids.first)
          expects_array ? [ result ] : result
        else
          find_some(ids)
        end
      end

      def find_one(id)
        if ActiveRecord::Base === id
          raise ArgumentError, <<-MSG.squish
            You are passing an instance of ActiveRecord::Base to `find`.
            Please pass the id of the object by calling `.id`.
          MSG
        end

        relation = where(primary_key => id)
        record = relation.take

        raise_record_not_found_exception!(id, 0, 1) unless record

        record
      end

      def find_some(ids)
        return find_some_ordered(ids) unless order_values.present?

        result = where(primary_key => ids).to_a

        expected_size =
          if limit_value && ids.size > limit_value
            limit_value
          else
            ids.size
          end

        # 11 ids with limit 3, offset 9 should give 2 results.
        if offset_value && (ids.size - offset_value < expected_size)
          expected_size = ids.size - offset_value
        end

        if result.size == expected_size
          result
        else
          raise_record_not_found_exception!(ids, result.size, expected_size)
        end
      end

      def find_some_ordered(ids)
        ids = ids.slice(offset_value || 0, limit_value || ids.size) || []

        result = except(:limit, :offset).where(primary_key => ids).records

        if result.size == ids.size
          result.in_order_of(:id, ids.map { |id| @klass.type_for_attribute(primary_key).cast(id) })
        else
          raise_record_not_found_exception!(ids, result.size, ids.size)
        end
      end

      def find_take
        if loaded?
          records.first
        else
          @take ||= limit(1).records.first
        end
      end

      def find_take_with_limit(limit)
        if loaded?
          records.take(limit)
        else
          limit(limit).to_a
        end
      end

      def find_nth(index)
        @offsets ||= {}
        @offsets[index] ||= find_nth_with_limit(index, 1).first
      end

      def find_nth_with_limit(index, limit)
        if loaded?
          records[index, limit] || []
        else
          relation = ordered_relation

          if limit_value
            limit = [limit_value - index, limit].min
          end

          if limit > 0
            relation = relation.offset((offset_value || 0) + index) unless index.zero?
            relation.limit(limit).to_a
          else
            []
          end
        end
      end

      def find_nth_from_last(index)
        if loaded?
          records[-index]
        else
          relation = ordered_relation

          if equal?(relation) || has_limit_or_offset?
            relation.records[-index]
          else
            relation.last(index)[-index]
          end
        end
      end

      def find_last(limit)
        limit ? records.last(limit) : records.last
      end

      def ordered_relation
        if order_values.empty? && (implicit_order_column || primary_key)
          if implicit_order_column && primary_key && implicit_order_column != primary_key
            order(table[implicit_order_column].asc, table[primary_key].asc)
          else
            order(table[implicit_order_column || primary_key].asc)
          end
        else
          self
        end
      end
  end
end

fixtures.rb

# frozen_string_literal: true

require "erb"
require "yaml"
require "zlib"
require "set"
require "active_support/dependencies"
require "active_support/core_ext/digest/uuid"
require "active_record/fixture_set/file"
require "active_record/fixture_set/render_context"
require "active_record/fixture_set/table_rows"
require "active_record/test_fixtures"

module ActiveRecord
  class FixtureClassNotFound < ActiveRecord::ActiveRecordError # :nodoc:
  end

  # \Fixtures are a way of organizing data that you want to test against; in short, sample data.
  #
  # They are stored in YAML files, one file per model, which are placed in the directory
  # appointed by <tt>ActiveSupport::TestCase.fixture_path=(path)</tt> (this is automatically
  # configured for Rails, so you can just put your files in <tt><your-rails-app>/test/fixtures/</tt>).
  # The fixture file ends with the +.yml+ file extension, for example:
  # <tt><your-rails-app>/test/fixtures/web_sites.yml</tt>).
  #
  # The format of a fixture file looks like this:
  #
  #   rubyonrails:
  #     id: 1
  #     name: Ruby on Rails
  #     url: http://www.rubyonrails.org
  #
  #   google:
  #     id: 2
  #     name: Google
  #     url: http://www.google.com
  #
  # This fixture file includes two fixtures. Each YAML fixture (i.e. record) is given a name and
  # is followed by an indented list of key/value pairs in the "key: value" format. Records are
  # separated by a blank line for your viewing pleasure.
  #
  # Note: Fixtures are unordered. If you want ordered fixtures, use the omap YAML type.
  # See https://yaml.org/type/omap.html
  # for the specification. You will need ordered fixtures when you have foreign key constraints
  # on keys in the same table. This is commonly needed for tree structures. Example:
  #
  #    --- !omap
  #    - parent:
  #        id:         1
  #        parent_id:  NULL
  #        title:      Parent
  #    - child:
  #        id:         2
  #        parent_id:  1
  #        title:      Child
  #
  # = Using Fixtures in Test Cases
  #
  # Since fixtures are a testing construct, we use them in our unit and functional tests. There
  # are two ways to use the fixtures, but first let's take a look at a sample unit test:
  #
  #   require "test_helper"
  #
  #   class WebSiteTest < ActiveSupport::TestCase
  #     test "web_site_count" do
  #       assert_equal 2, WebSite.count
  #     end
  #   end
  #
  # By default, +test_helper.rb+ will load all of your fixtures into your test
  # database, so this test will succeed.
  #
  # The testing environment will automatically load all the fixtures into the database before each
  # test. To ensure consistent data, the environment deletes the fixtures before running the load.
  #
  # In addition to being available in the database, the fixture's data may also be accessed by
  # using a special dynamic method, which has the same name as the model.
  #
  # Passing in a fixture name to this dynamic method returns the fixture matching this name:
  #
  #   test "find one" do
  #     assert_equal "Ruby on Rails", web_sites(:rubyonrails).name
  #   end
  #
  # Passing in multiple fixture names returns all fixtures matching these names:
  #
  #   test "find all by name" do
  #     assert_equal 2, web_sites(:rubyonrails, :google).length
  #   end
  #
  # Passing in no arguments returns all fixtures:
  #
  #   test "find all" do
  #     assert_equal 2, web_sites.length
  #   end
  #
  # Passing in any fixture name that does not exist will raise <tt>StandardError</tt>:
  #
  #   test "find by name that does not exist" do
  #     assert_raise(StandardError) { web_sites(:reddit) }
  #   end
  #
  # Alternatively, you may enable auto-instantiation of the fixture data. For instance, take the
  # following tests:
  #
  #   test "find_alt_method_1" do
  #     assert_equal "Ruby on Rails", @web_sites['rubyonrails']['name']
  #   end
  #
  #   test "find_alt_method_2" do
  #     assert_equal "Ruby on Rails", @rubyonrails.name
  #   end
  #
  # In order to use these methods to access fixtured data within your test cases, you must specify one of the
  # following in your ActiveSupport::TestCase-derived class:
  #
  # - to fully enable instantiated fixtures (enable alternate methods #1 and #2 above)
  #     self.use_instantiated_fixtures = true
  #
  # - create only the hash for the fixtures, do not 'find' each instance (enable alternate method #1 only)
  #     self.use_instantiated_fixtures = :no_instances
  #
  # Using either of these alternate methods incurs a performance hit, as the fixtured data must be fully
  # traversed in the database to create the fixture hash and/or instance variables. This is expensive for
  # large sets of fixtured data.
  #
  # = Dynamic fixtures with ERB
  #
  # Sometimes you don't care about the content of the fixtures as much as you care about the volume.
  # In these cases, you can mix ERB in with your YAML fixtures to create a bunch of fixtures for load
  # testing, like:
  #
  #   <% 1.upto(1000) do |i| %>
  #   fix_<%= i %>:
  #     id: <%= i %>
  #     name: guy_<%= i %>
  #   <% end %>
  #
  # This will create 1000 very simple fixtures.
  #
  # Using ERB, you can also inject dynamic values into your fixtures with inserts like
  # <tt><%= Date.today.strftime("%Y-%m-%d") %></tt>.
  # This is however a feature to be used with some caution. The point of fixtures are that they're
  # stable units of predictable sample data. If you feel that you need to inject dynamic values, then
  # perhaps you should reexamine whether your application is properly testable. Hence, dynamic values
  # in fixtures are to be considered a code smell.
  #
  # Helper methods defined in a fixture will not be available in other fixtures, to prevent against
  # unwanted inter-test dependencies. Methods used by multiple fixtures should be defined in a module
  # that is included in ActiveRecord::FixtureSet.context_class.
  #
  # - define a helper method in <tt>test_helper.rb</tt>
  #     module FixtureFileHelpers
  #       def file_sha(path)
  #         OpenSSL::Digest::SHA256.hexdigest(File.read(Rails.root.join('test/fixtures', path)))
  #       end
  #     end
  #     ActiveRecord::FixtureSet.context_class.include FixtureFileHelpers
  #
  # - use the helper method in a fixture
  #     photo:
  #       name: kitten.png
  #       sha: <%= file_sha 'files/kitten.png' %>
  #
  # = Transactional Tests
  #
  # Test cases can use begin+rollback to isolate their changes to the database instead of having to
  # delete+insert for every test case.
  #
  #   class FooTest < ActiveSupport::TestCase
  #     self.use_transactional_tests = true
  #
  #     test "godzilla" do
  #       assert_not_empty Foo.all
  #       Foo.destroy_all
  #       assert_empty Foo.all
  #     end
  #
  #     test "godzilla aftermath" do
  #       assert_not_empty Foo.all
  #     end
  #   end
  #
  # If you preload your test database with all fixture data (probably by running <tt>bin/rails db:fixtures:load</tt>)
  # and use transactional tests, then you may omit all fixtures declarations in your test cases since
  # all the data's already there and every case rolls back its changes.
  #
  # In order to use instantiated fixtures with preloaded data, set +self.pre_loaded_fixtures+ to
  # true. This will provide access to fixture data for every table that has been loaded through
  # fixtures (depending on the value of +use_instantiated_fixtures+).
  #
  # When *not* to use transactional tests:
  #
  # 1. You're testing whether a transaction works correctly. Nested transactions don't commit until
  #    all parent transactions commit, particularly, the fixtures transaction which is begun in setup
  #    and rolled back in teardown. Thus, you won't be able to verify
  #    the results of your transaction until Active Record supports nested transactions or savepoints (in progress).
  # 2. Your database does not support transactions. Every Active Record database supports transactions except MySQL MyISAM.
  #    Use InnoDB, MaxDB, or NDB instead.
  #
  # = Advanced Fixtures
  #
  # Fixtures that don't specify an ID get some extra features:
  #
  # * Stable, autogenerated IDs
  # * Label references for associations (belongs_to, has_one, has_many)
  # * HABTM associations as inline lists
  #
  # There are some more advanced features available even if the id is specified:
  #
  # * Autofilled timestamp columns
  # * Fixture label interpolation
  # * Support for YAML defaults
  #
  # == Stable, Autogenerated IDs
  #
  # Here, have a monkey fixture:
  #
  #   george:
  #     id: 1
  #     name: George the Monkey
  #
  #   reginald:
  #     id: 2
  #     name: Reginald the Pirate
  #
  # Each of these fixtures has two unique identifiers: one for the database
  # and one for the humans. Why don't we generate the primary key instead?
  # Hashing each fixture's label yields a consistent ID:
  #
  #   george: # generated id: 503576764
  #     name: George the Monkey
  #
  #   reginald: # generated id: 324201669
  #     name: Reginald the Pirate
  #
  # Active Record looks at the fixture's model class, discovers the correct
  # primary key, and generates it right before inserting the fixture
  # into the database.
  #
  # The generated ID for a given label is constant, so we can discover
  # any fixture's ID without loading anything, as long as we know the label.
  #
  # == Label references for associations (+belongs_to+, +has_one+, +has_many+)
  #
  # Specifying foreign keys in fixtures can be very fragile, not to
  # mention difficult to read. Since Active Record can figure out the ID of
  # any fixture from its label, you can specify FK's by label instead of ID.
  #
  # === +belongs_to+
  #
  # Let's break out some more monkeys and pirates.
  #
  #   ### in pirates.yml
  #
  #   reginald:
  #     id: 1
  #     name: Reginald the Pirate
  #     monkey_id: 1
  #
  #   ### in monkeys.yml
  #
  #   george:
  #     id: 1
  #     name: George the Monkey
  #     pirate_id: 1
  #
  # Add a few more monkeys and pirates and break this into multiple files,
  # and it gets pretty hard to keep track of what's going on. Let's
  # use labels instead of IDs:
  #
  #   ### in pirates.yml
  #
  #   reginald:
  #     name: Reginald the Pirate
  #     monkey: george
  #
  #   ### in monkeys.yml
  #
  #   george:
  #     name: George the Monkey
  #     pirate: reginald
  #
  # Pow! All is made clear. Active Record reflects on the fixture's model class,
  # finds all the +belongs_to+ associations, and allows you to specify
  # a target *label* for the *association* (monkey: george) rather than
  # a target *id* for the *FK* (<tt>monkey_id: 1</tt>).
  #
  # ==== Polymorphic +belongs_to+
  #
  # Supporting polymorphic relationships is a little bit more complicated, since
  # Active Record needs to know what type your association is pointing at. Something
  # like this should look familiar:
  #
  #   ### in fruit.rb
  #
  #   belongs_to :eater, polymorphic: true
  #
  #   ### in fruits.yml
  #
  #   apple:
  #     id: 1
  #     name: apple
  #     eater_id: 1
  #     eater_type: Monkey
  #
  # Can we do better? You bet!
  #
  #   apple:
  #     eater: george (Monkey)
  #
  # Just provide the polymorphic target type and Active Record will take care of the rest.
  #
  # === +has_and_belongs_to_many+ or <tt>has_many :through</tt>
  #
  # Time to give our monkey some fruit.
  #
  #   ### in monkeys.yml
  #
  #   george:
  #     id: 1
  #     name: George the Monkey
  #
  #   ### in fruits.yml
  #
  #   apple:
  #     id: 1
  #     name: apple
  #
  #   orange:
  #     id: 2
  #     name: orange
  #
  #   grape:
  #     id: 3
  #     name: grape
  #
  #   ### in fruits_monkeys.yml
  #
  #   apple_george:
  #     fruit_id: 1
  #     monkey_id: 1
  #
  #   orange_george:
  #     fruit_id: 2
  #     monkey_id: 1
  #
  #   grape_george:
  #     fruit_id: 3
  #     monkey_id: 1
  #
  # Let's make the HABTM fixture go away.
  #
  #   ### in monkeys.yml
  #
  #   george:
  #     id: 1
  #     name: George the Monkey
  #     fruits: apple, orange, grape
  #
  #   ### in fruits.yml
  #
  #   apple:
  #     name: apple
  #
  #   orange:
  #     name: orange
  #
  #   grape:
  #     name: grape
  #
  # Zap! No more fruits_monkeys.yml file. We've specified the list of fruits
  # on George's fixture, but we could've just as easily specified a list
  # of monkeys on each fruit. As with +belongs_to+, Active Record reflects on
  # the fixture's model class and discovers the +has_and_belongs_to_many+
  # associations.
  #
  # == Autofilled Timestamp Columns
  #
  # If your table/model specifies any of Active Record's
  # standard timestamp columns (+created_at+, +created_on+, +updated_at+, +updated_on+),
  # they will automatically be set to <tt>Time.now</tt>.
  #
  # If you've set specific values, they'll be left alone.
  #
  # == Fixture label interpolation
  #
  # The label of the current fixture is always available as a column value:
  #
  #   geeksomnia:
  #     name: Geeksomnia's Account
  #     subdomain: $LABEL
  #     email: $LABEL@email.com
  #
  # Also, sometimes (like when porting older join table fixtures) you'll need
  # to be able to get a hold of the identifier for a given label. ERB
  # to the rescue:
  #
  #   george_reginald:
  #     monkey_id: <%= ActiveRecord::FixtureSet.identify(:reginald) %>
  #     pirate_id: <%= ActiveRecord::FixtureSet.identify(:george) %>
  #
  # == Support for YAML defaults
  #
  # You can set and reuse defaults in your fixtures YAML file.
  # This is the same technique used in the +database.yml+ file to specify
  # defaults:
  #
  #   DEFAULTS: &DEFAULTS
  #     created_on: <%= 3.weeks.ago.to_fs(:db) %>
  #
  #   first:
  #     name: Smurf
  #     <<: *DEFAULTS
  #
  #   second:
  #     name: Fraggle
  #     <<: *DEFAULTS
  #
  # Any fixture labeled "DEFAULTS" is safely ignored.
  #
  # Besides using "DEFAULTS", you can also specify what fixtures will
  # be ignored by setting "ignore" in "_fixture" section.
  #
  #   # users.yml
  #   _fixture:
  #     ignore:
  #       - base
  #     # or use "ignore: base" when there is only one fixture that needs to be ignored.
  #
  #   base: &base
  #     admin: false
  #     introduction: "This is a default description"
  #
  #   admin:
  #     <<: *base
  #     admin: true
  #
  #   visitor:
  #     <<: *base
  #
  # In the above example, 'base' will be ignored when creating fixtures.
  # This can be used for common attributes inheriting.
  #
  # == Configure the fixture model class
  #
  # It's possible to set the fixture's model class directly in the YAML file.
  # This is helpful when fixtures are loaded outside tests and
  # +set_fixture_class+ is not available (e.g.
  # when running <tt>bin/rails db:fixtures:load</tt>).
  #
  #   _fixture:
  #     model_class: User
  #   david:
  #     name: David
  #
  # Any fixtures labeled "_fixture" are safely ignored.
  class FixtureSet
    #--
    # An instance of FixtureSet is normally stored in a single YAML file and
    # possibly in a folder with the same name.
    #++

    MAX_ID = 2**30 - 1

    @@all_cached_fixtures = Hash.new { |h, k| h[k] = {} }

    cattr_accessor :all_loaded_fixtures, default: {}

    class ClassCache
      def initialize(class_names, config)
        @class_names = class_names.stringify_keys
        @config      = config

        # Remove string values that aren't constants or subclasses of AR
        @class_names.delete_if do |klass_name, klass|
          !insert_class(@class_names, klass_name, klass)
        end
      end

      def [](fs_name)
        @class_names.fetch(fs_name) do
          klass = default_fixture_model(fs_name, @config).safe_constantize
          insert_class(@class_names, fs_name, klass)
        end
      end

      private
        def insert_class(class_names, name, klass)
          # We only want to deal with AR objects.
          if klass && klass < ActiveRecord::Base
            class_names[name] = klass
          else
            class_names[name] = nil
          end
        end

        def default_fixture_model(fs_name, config)
          ActiveRecord::FixtureSet.default_fixture_model_name(fs_name, config)
        end
    end

    class << self
      def default_fixture_model_name(fixture_set_name, config = ActiveRecord::Base) # :nodoc:
        config.pluralize_table_names ?
          fixture_set_name.singularize.camelize :
          fixture_set_name.camelize
      end

      def default_fixture_table_name(fixture_set_name, config = ActiveRecord::Base) # :nodoc:
        "#{ config.table_name_prefix }"\
        "#{ fixture_set_name.tr('/', '_') }"\
        "#{ config.table_name_suffix }".to_sym
      end

      def reset_cache
        @@all_cached_fixtures.clear
      end

      def cache_for_connection(connection)
        @@all_cached_fixtures[connection]
      end

      def fixture_is_cached?(connection, table_name)
        cache_for_connection(connection)[table_name]
      end

      def cached_fixtures(connection, keys_to_fetch = nil)
        if keys_to_fetch
          cache_for_connection(connection).values_at(*keys_to_fetch)
        else
          cache_for_connection(connection).values
        end
      end

      def cache_fixtures(connection, fixtures_map)
        cache_for_connection(connection).update(fixtures_map)
      end

      def instantiate_fixtures(object, fixture_set, load_instances = true)
        return unless load_instances
        fixture_set.each do |fixture_name, fixture|
          object.instance_variable_set "@#{fixture_name}", fixture.find
        rescue FixtureClassNotFound
          nil
        end
      end

      def instantiate_all_loaded_fixtures(object, load_instances = true)
        all_loaded_fixtures.each_value do |fixture_set|
          instantiate_fixtures(object, fixture_set, load_instances)
        end
      end

      def create_fixtures(fixtures_directory, fixture_set_names, class_names = {}, config = ActiveRecord::Base, &block)
        fixture_set_names = Array(fixture_set_names).map(&:to_s)
        class_names = ClassCache.new class_names, config

        # FIXME: Apparently JK uses this.
        connection = block_given? ? block : lambda { ActiveRecord::Base.connection }

        fixture_files_to_read = fixture_set_names.reject do |fs_name|
          fixture_is_cached?(connection.call, fs_name)
        end

        if fixture_files_to_read.any?
          fixtures_map = read_and_insert(
            fixtures_directory,
            fixture_files_to_read,
            class_names,
            connection,
          )
          cache_fixtures(connection.call, fixtures_map)
        end
        cached_fixtures(connection.call, fixture_set_names)
      end

      # Returns a consistent, platform-independent identifier for +label+.
      # Integer identifiers are values less than 2^30. UUIDs are RFC 4122 version 5 SHA-1 hashes.
      def identify(label, column_type = :integer)
        if column_type == :uuid
          Digest::UUID.uuid_v5(Digest::UUID::OID_NAMESPACE, label.to_s)
        else
          Zlib.crc32(label.to_s) % MAX_ID
        end
      end

      # Superclass for the evaluation contexts used by ERB fixtures.
      def context_class
        @context_class ||= Class.new
      end

      private
        def read_and_insert(fixtures_directory, fixture_files, class_names, connection) # :nodoc:
          fixtures_map = {}
          fixture_sets = fixture_files.map do |fixture_set_name|
            klass = class_names[fixture_set_name]
            fixtures_map[fixture_set_name] = new( # ActiveRecord::FixtureSet.new
              nil,
              fixture_set_name,
              klass,
              ::File.join(fixtures_directory, fixture_set_name)
            )
          end
          update_all_loaded_fixtures(fixtures_map)

          insert(fixture_sets, connection)

          fixtures_map
        end

        def insert(fixture_sets, connection) # :nodoc:
          fixture_sets_by_connection = fixture_sets.group_by do |fixture_set|
            if fixture_set.model_class
              fixture_set.model_class.connection
            else
              connection.call
            end
          end

          fixture_sets_by_connection.each do |conn, set|
            table_rows_for_connection = Hash.new { |h, k| h[k] = [] }

            set.each do |fixture_set|
              fixture_set.table_rows.each do |table, rows|
                table_rows_for_connection[table].unshift(*rows)
              end
            end

            conn.insert_fixtures_set(table_rows_for_connection, table_rows_for_connection.keys)

            if ActiveRecord.verify_foreign_keys_for_fixtures && !conn.all_foreign_keys_valid?
              raise "Foreign key violations found in your fixture data. Ensure you aren't referring to labels that don't exist on associations."
            end

            # Cap primary key sequences to max(pk).
            if conn.respond_to?(:reset_pk_sequence!)
              set.each { |fs| conn.reset_pk_sequence!(fs.table_name) }
            end
          end
        end

        def update_all_loaded_fixtures(fixtures_map) # :nodoc:
          all_loaded_fixtures.update(fixtures_map)
        end
    end

    attr_reader :table_name, :name, :fixtures, :model_class, :ignored_fixtures, :config

    def initialize(_, name, class_name, path, config = ActiveRecord::Base)
      @name     = name
      @path     = path
      @config   = config

      self.model_class = class_name

      @fixtures = read_fixture_files(path)

      @table_name = model_class&.table_name || self.class.default_fixture_table_name(name, config)
    end

    def [](x)
      fixtures[x]
    end

    def []=(k, v)
      fixtures[k] = v
    end

    def each(&block)
      fixtures.each(&block)
    end

    def size
      fixtures.size
    end

    # Returns a hash of rows to be inserted. The key is the table, the value is
    # a list of rows to insert to that table.
    def table_rows
      # allow specifying fixtures to be ignored by setting `ignore` in `_fixture` section
      fixtures.except!(*ignored_fixtures)

      TableRows.new(
        table_name,
        model_class: model_class,
        fixtures: fixtures,
      ).to_hash
    end

    private
      def model_class=(class_name)
        if class_name.is_a?(Class) # TODO: Should be an AR::Base type class, or any?
          @model_class = class_name
        else
          @model_class = class_name.safe_constantize if class_name
        end
      end

      def ignored_fixtures=(base)
        @ignored_fixtures =
            case base
            when Array
              base
            when String
              [base]
            else
              []
            end

        @ignored_fixtures << "DEFAULTS" unless @ignored_fixtures.include?("DEFAULTS")
        @ignored_fixtures.compact
      end

      # Loads the fixtures from the YAML file at +path+.
      # If the file sets the +model_class+ and current instance value is not set,
      # it uses the file value.
      def read_fixture_files(path)
        yaml_files = Dir["#{path}/{**,*}/*.yml"].select { |f|
          ::File.file?(f)
        } + [yaml_file_path(path)]

        yaml_files.each_with_object({}) do |file, fixtures|
          FixtureSet::File.open(file) do |fh|
            self.model_class ||= fh.model_class if fh.model_class
            self.ignored_fixtures ||= fh.ignored_fixtures
            fh.each do |fixture_name, row|
              fixtures[fixture_name] = ActiveRecord::Fixture.new(row, model_class)
            end
          end
        end
      end

      def yaml_file_path(path)
        "#{path}.yml"
      end
  end

  class Fixture # :nodoc:
    include Enumerable

    class FixtureError < StandardError # :nodoc:
    end

    class FormatError < FixtureError # :nodoc:
    end

    attr_reader :model_class, :fixture

    def initialize(fixture, model_class)
      @fixture     = fixture
      @model_class = model_class
    end

    def class_name
      model_class.name if model_class
    end

    def each(&block)
      fixture.each(&block)
    end

    def [](key)
      fixture[key]
    end

    alias :to_hash :fixture

    def find
      raise FixtureClassNotFound, "No class attached to find." unless model_class
      object = model_class.unscoped do
        model_class.find(fixture[model_class.primary_key])
      end
      # Fixtures can't be eagerly loaded
      object.instance_variable_set(:@strict_loading, false)
      object
    end
  end
end

ActiveSupport.run_load_hooks :active_record_fixture_set, ActiveRecord::FixtureSet

foreign_association.rb

# frozen_string_literal: true

module ActiveRecord::Associations
  module ForeignAssociation # :nodoc:
    def foreign_key_present?
      if reflection.klass.primary_key
        owner.attribute_present?(reflection.active_record_primary_key)
      else
        false
      end
    end

    def nullified_owner_attributes
      Hash.new.tap do |attrs|
        attrs[reflection.foreign_key] = nil
        attrs[reflection.type] = nil if reflection.type.present?
      end
    end

    private
      # Sets the owner attributes on the given record
      def set_owner_attributes(record)
        return if options[:through]

        key = owner._read_attribute(reflection.join_foreign_key)
        record._write_attribute(reflection.join_primary_key, key)

        if reflection.type
          record._write_attribute(reflection.type, owner.class.polymorphic_name)
        end
      end
  end
end

from_clause.rb

# frozen_string_literal: true

module ActiveRecord
  class Relation
    class FromClause # :nodoc:
      attr_reader :value, :name

      def initialize(value, name)
        @value = value
        @name = name
      end

      def merge(other)
        self
      end

      def empty?
        value.nil?
      end

      def ==(other)
        self.class == other.class && value == other.value && name == other.name
      end

      def self.empty
        @empty ||= new(nil, nil).freeze
      end
    end
  end
end

full_outer_join.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class FullOuterJoin < Arel::Nodes::Join
    end
  end
end

function.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Function < Arel::Nodes::NodeExpression
      include Arel::WindowPredications
      include Arel::FilterPredications
      attr_accessor :expressions, :alias, :distinct

      def initialize(expr, aliaz = nil)
        super()
        @expressions = expr
        @alias       = aliaz && SqlLiteral.new(aliaz)
        @distinct    = false
      end

      def as(aliaz)
        self.alias = SqlLiteral.new(aliaz)
        self
      end

      def hash
        [@expressions, @alias, @distinct].hash
      end

      def eql?(other)
        self.class == other.class &&
          self.expressions == other.expressions &&
          self.alias == other.alias &&
          self.distinct == other.distinct
      end
      alias :== :eql?
    end

    %w{
      Sum
      Exists
      Max
      Min
      Avg
    }.each do |name|
      const_set(name, Class.new(Function))
    end
  end
end

future_result.rb

# frozen_string_literal: true

module ActiveRecord
  class FutureResult # :nodoc:
    class EventBuffer
      def initialize(future_result, instrumenter)
        @future_result = future_result
        @instrumenter = instrumenter
        @events = []
      end

      def instrument(name, payload = {}, &block)
        event = @instrumenter.new_event(name, payload)
        @events << event
        event.record(&block)
      end

      def flush
        events, @events = @events, []
        events.each do |event|
          event.payload[:lock_wait] = @future_result.lock_wait
          ActiveSupport::Notifications.publish_event(event)
        end
      end
    end

    Canceled = Class.new(ActiveRecordError)

    delegate :empty?, :to_a, to: :result

    attr_reader :lock_wait

    def initialize(pool, *args, **kwargs)
      @mutex = Mutex.new

      @session = nil
      @pool = pool
      @args = args
      @kwargs = kwargs

      @pending = true
      @error = nil
      @result = nil
      @instrumenter = ActiveSupport::Notifications.instrumenter
      @event_buffer = nil
    end

    def schedule!(session)
      @session = session
      @pool.schedule_query(self)
    end

    def execute!(connection)
      execute_query(connection)
    end

    def cancel
      @pending = false
      @error = Canceled
      self
    end

    def execute_or_skip
      return unless pending?

      @pool.with_connection do |connection|
        return unless @mutex.try_lock
        begin
          if pending?
            @event_buffer = EventBuffer.new(self, @instrumenter)
            connection.with_instrumenter(@event_buffer) do
              execute_query(connection, async: true)
            end
          end
        ensure
          @mutex.unlock
        end
      end
    end

    def result
      execute_or_wait
      @event_buffer&.flush

      if canceled?
        raise Canceled
      elsif @error
        raise @error
      else
        @result
      end
    end

    def pending?
      @pending && (!@session || @session.active?)
    end

    private
      def canceled?
        @session && !@session.active?
      end

      def execute_or_wait
        if pending?
          start = Process.clock_gettime(Process::CLOCK_MONOTONIC, :float_millisecond)
          @mutex.synchronize do
            if pending?
              execute_query(@pool.connection)
            else
              @lock_wait = (Process.clock_gettime(Process::CLOCK_MONOTONIC, :float_millisecond) - start)
            end
          end
        else
          @lock_wait = 0.0
        end
      end

      def execute_query(connection, async: false)
        @result = exec_query(connection, *@args, **@kwargs, async: async)
      rescue => error
        @error = error
      ensure
        @pending = false
      end

      def exec_query(connection, *args, **kwargs)
        connection.exec_query(*args, **kwargs)
      end

      class SelectAll < FutureResult # :nodoc:
        private
          def exec_query(*, **)
            super
          rescue ::RangeError
            ActiveRecord::Result.empty
          end
      end
  end
end

gem_version.rb

# frozen_string_literal: true

module ActiveRecord
  # Returns the version of the currently loaded Active Record as a <tt>Gem::Version</tt>
  def self.gem_version
    Gem::Version.new VERSION::STRING
  end

  module VERSION
    MAJOR = 7
    MINOR = 1
    TINY  = 0
    PRE   = "alpha"

    STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
  end
end

grouping.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Grouping < Unary
      def fetch_attribute(&block)
        expr.fetch_attribute(&block)
      end
    end
  end
end

has_and_belongs_to_many.rb

# frozen_string_literal: true

module ActiveRecord::Associations::Builder # :nodoc:
  class HasAndBelongsToMany # :nodoc:
    attr_reader :lhs_model, :association_name, :options

    def initialize(association_name, lhs_model, options)
      @association_name = association_name
      @lhs_model = lhs_model
      @options = options
    end

    def through_model
      join_model = Class.new(ActiveRecord::Base) {
        class << self
          attr_accessor :left_model
          attr_accessor :name
          attr_accessor :table_name_resolver
          attr_accessor :left_reflection
          attr_accessor :right_reflection
        end

        def self.table_name
          # Table name needs to be resolved lazily
          # because RHS class might not have been loaded
          @table_name ||= table_name_resolver.call
        end

        def self.compute_type(class_name)
          left_model.compute_type class_name
        end

        def self.add_left_association(name, options)
          belongs_to name, required: false, **options
          self.left_reflection = _reflect_on_association(name)
        end

        def self.add_right_association(name, options)
          rhs_name = name.to_s.singularize.to_sym
          belongs_to rhs_name, required: false, **options
          self.right_reflection = _reflect_on_association(rhs_name)
        end

        def self.retrieve_connection
          left_model.retrieve_connection
        end

        private
          def self.suppress_composite_primary_key(pk)
            pk unless pk.is_a?(Array)
          end
      }

      join_model.name                = "HABTM_#{association_name.to_s.camelize}"
      join_model.table_name_resolver = -> { table_name }
      join_model.left_model          = lhs_model

      join_model.add_left_association :left_side, anonymous_class: lhs_model
      join_model.add_right_association association_name, belongs_to_options(options)
      join_model
    end

    def middle_reflection(join_model)
      middle_name = [lhs_model.name.downcase.pluralize,
                     association_name.to_s].sort.join("_").gsub("::", "_").to_sym
      middle_options = middle_options join_model

      HasMany.create_reflection(lhs_model,
                                middle_name,
                                nil,
                                middle_options)
    end

    private
      def middle_options(join_model)
        middle_options = {}
        middle_options[:class_name] = "#{lhs_model.name}::#{join_model.name}"
        if options.key? :foreign_key
          middle_options[:foreign_key] = options[:foreign_key]
        end
        middle_options
      end

      def table_name
        if options[:join_table]
          options[:join_table].to_s
        else
          class_name = options.fetch(:class_name) {
            association_name.to_s.camelize.singularize
          }
          klass = lhs_model.send(:compute_type, class_name.to_s)
          [lhs_model.table_name, klass.table_name].sort.join("\0").gsub(/^(.*[._])(.+)\0\1(.+)/, '\1\2_\3').tr("\0", "_")
        end
      end

      def belongs_to_options(options)
        rhs_options = {}

        if options.key? :class_name
          rhs_options[:foreign_key] = options[:class_name].to_s.foreign_key
          rhs_options[:class_name] = options[:class_name]
        end

        if options.key? :association_foreign_key
          rhs_options[:foreign_key] = options[:association_foreign_key]
        end

        rhs_options
      end
  end
end

has_many.rb

# frozen_string_literal: true

module ActiveRecord::Associations::Builder # :nodoc:
  class HasMany < CollectionAssociation # :nodoc:
    def self.macro
      :has_many
    end

    def self.valid_options(options)
      valid = super + [:counter_cache, :join_table, :index_errors]
      valid += [:as, :foreign_type] if options[:as]
      valid += [:through, :source, :source_type] if options[:through]
      valid += [:ensuring_owner_was] if options[:dependent] == :destroy_async
      valid += [:disable_joins] if options[:disable_joins] && options[:through]
      valid
    end

    def self.valid_dependent_options
      [:destroy, :delete_all, :nullify, :restrict_with_error, :restrict_with_exception, :destroy_async]
    end

    private_class_method :macro, :valid_options, :valid_dependent_options
  end
end

has_many_association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    # = Active Record Has Many Association
    # This is the proxy that handles a has many association.
    #
    # If the association has a <tt>:through</tt> option further specialization
    # is provided by its child HasManyThroughAssociation.
    class HasManyAssociation < CollectionAssociation # :nodoc:
      include ForeignAssociation

      def handle_dependency
        case options[:dependent]
        when :restrict_with_exception
          raise ActiveRecord::DeleteRestrictionError.new(reflection.name) unless empty?

        when :restrict_with_error
          unless empty?
            record = owner.class.human_attribute_name(reflection.name).downcase
            owner.errors.add(:base, :'restrict_dependent_destroy.has_many', record: record)
            throw(:abort)
          end

        when :destroy
          # No point in executing the counter update since we're going to destroy the parent anyway
          load_target.each { |t| t.destroyed_by_association = reflection }
          destroy_all
        when :destroy_async
          load_target.each do |t|
            t.destroyed_by_association = reflection
          end

          unless target.empty?
            association_class = target.first.class
            primary_key_column = association_class.primary_key.to_sym

            ids = target.collect do |assoc|
              assoc.public_send(primary_key_column)
            end

            enqueue_destroy_association(
              owner_model_name: owner.class.to_s,
              owner_id: owner.id,
              association_class: reflection.klass.to_s,
              association_ids: ids,
              association_primary_key_column: primary_key_column,
              ensuring_owner_was_method: options.fetch(:ensuring_owner_was, nil)
            )
          end
        else
          delete_all
        end
      end

      def insert_record(record, validate = true, raise = false)
        set_owner_attributes(record)
        super
      end

      private
        # Returns the number of records in this collection.
        #
        # If the association has a counter cache it gets that value. Otherwise
        # it will attempt to do a count via SQL, bounded to <tt>:limit</tt> if
        # there's one. Some configuration options like :group make it impossible
        # to do an SQL count, in those cases the array count will be used.
        #
        # That does not depend on whether the collection has already been loaded
        # or not. The +size+ method is the one that takes the loaded flag into
        # account and delegates to +count_records+ if needed.
        #
        # If the collection is empty the target is set to an empty array and
        # the loaded flag is set to true as well.
        def count_records
          count = if reflection.has_cached_counter?
            owner.read_attribute(reflection.counter_cache_column).to_i
          else
            scope.count(:all)
          end

          # If there's nothing in the database and @target has no new records
          # we are certain the current target is an empty array. This is a
          # documented side-effect of the method that may avoid an extra SELECT.
          loaded! if count == 0

          [association_scope.limit_value, count].compact.min
        end

        def update_counter(difference, reflection = reflection())
          if reflection.has_cached_counter?
            owner.increment!(reflection.counter_cache_column, difference)
          end
        end

        def update_counter_in_memory(difference, reflection = reflection())
          if reflection.counter_must_be_updated_by_has_many?
            counter = reflection.counter_cache_column
            owner.increment(counter, difference)
            owner.send(:"clear_#{counter}_change")
          end
        end

        def delete_count(method, scope)
          if method == :delete_all
            scope.delete_all
          else
            scope.update_all(nullified_owner_attributes)
          end
        end

        def delete_or_nullify_all_records(method)
          count = delete_count(method, scope)
          update_counter(-count)
          count
        end

        # Deletes the records according to the <tt>:dependent</tt> option.
        def delete_records(records, method)
          if method == :destroy
            records.each(&:destroy!)
            update_counter(-records.length) unless reflection.inverse_updates_counter_cache?
          else
            scope = self.scope.where(reflection.klass.primary_key => records)
            update_counter(-delete_count(method, scope))
          end
        end

        def concat_records(records, *)
          update_counter_if_success(super, records.length)
        end

        def _create_record(attributes, *)
          if attributes.is_a?(Array)
            super
          else
            update_counter_if_success(super, 1)
          end
        end

        def update_counter_if_success(saved_successfully, difference)
          if saved_successfully
            update_counter_in_memory(difference)
          end
          saved_successfully
        end

        def difference(a, b)
          a - b
        end

        def intersection(a, b)
          a & b
        end
    end
  end
end

has_many_through_association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    # = Active Record Has Many Through Association
    class HasManyThroughAssociation < HasManyAssociation # :nodoc:
      include ThroughAssociation

      def initialize(owner, reflection)
        super
        @through_records = {}.compare_by_identity
      end

      def concat(*records)
        unless owner.new_record?
          records.flatten.each do |record|
            raise_on_type_mismatch!(record)
          end
        end

        super
      end

      def insert_record(record, validate = true, raise = false)
        ensure_not_nested

        if record.new_record? || record.has_changes_to_save?
          return unless super
        end

        save_through_record(record)

        record
      end

      private
        def concat_records(records)
          ensure_not_nested

          records = super(records, true)

          if owner.new_record? && records
            records.flatten.each do |record|
              build_through_record(record)
            end
          end

          records
        end

        # The through record (built with build_record) is temporarily cached
        # so that it may be reused if insert_record is subsequently called.
        #
        # However, after insert_record has been called, the cache is cleared in
        # order to allow multiple instances of the same record in an association.
        def build_through_record(record)
          @through_records[record] ||= begin
            ensure_mutable

            attributes = through_scope_attributes
            attributes[source_reflection.name] = record
            attributes[source_reflection.foreign_type] = options[:source_type] if options[:source_type]

            through_association.build(attributes)
          end
        end

        attr_reader :through_scope

        def through_scope_attributes
          scope = through_scope || self.scope
          scope.where_values_hash(through_association.reflection.name.to_s).
            except!(through_association.reflection.foreign_key,
                    through_association.reflection.klass.inheritance_column)
        end

        def save_through_record(record)
          association = build_through_record(record)
          if association.changed?
            association.save!
          end
        ensure
          @through_records.delete(record)
        end

        def build_record(attributes)
          ensure_not_nested

          @through_scope = scope
          record = super

          inverse = source_reflection.inverse_of
          if inverse
            if inverse.collection?
              record.send(inverse.name) << build_through_record(record)
            elsif inverse.has_one?
              record.send("#{inverse.name}=", build_through_record(record))
            end
          end

          record
        ensure
          @through_scope = nil
        end

        def remove_records(existing_records, records, method)
          super
          delete_through_records(records)
        end

        def target_reflection_has_associated_record?
          !(through_reflection.belongs_to? && owner[through_reflection.foreign_key].blank?)
        end

        def update_through_counter?(method)
          case method
          when :destroy
            !through_reflection.inverse_updates_counter_cache?
          when :nullify
            false
          else
            true
          end
        end

        def delete_or_nullify_all_records(method)
          delete_records(load_target, method)
        end

        def delete_records(records, method)
          ensure_not_nested

          scope = through_association.scope
          scope.where! construct_join_attributes(*records)
          scope = scope.where(through_scope_attributes)

          case method
          when :destroy
            if scope.klass.primary_key
              count = scope.destroy_all.count(&:destroyed?)
            else
              scope.each(&:_run_destroy_callbacks)
              count = scope.delete_all
            end
          when :nullify
            count = scope.update_all(source_reflection.foreign_key => nil)
          else
            count = scope.delete_all
          end

          delete_through_records(records)

          if source_reflection.options[:counter_cache] && method != :destroy
            counter = source_reflection.counter_cache_column
            klass.decrement_counter counter, records.map(&:id)
          end

          if through_reflection.collection? && update_through_counter?(method)
            update_counter(-count, through_reflection)
          else
            update_counter(-count)
          end

          count
        end

        def difference(a, b)
          distribution = distribution(b)

          a.reject { |record| mark_occurrence(distribution, record) }
        end

        def intersection(a, b)
          distribution = distribution(b)

          a.select { |record| mark_occurrence(distribution, record) }
        end

        def mark_occurrence(distribution, record)
          distribution[record] > 0 && distribution[record] -= 1
        end

        def distribution(array)
          array.each_with_object(Hash.new(0)) do |record, distribution|
            distribution[record] += 1
          end
        end

        def through_records_for(record)
          attributes = construct_join_attributes(record)
          candidates = Array.wrap(through_association.target)
          candidates.find_all do |c|
            attributes.all? do |key, value|
              c.public_send(key) == value
            end
          end
        end

        def delete_through_records(records)
          records.each do |record|
            through_records = through_records_for(record)

            if through_reflection.collection?
              through_records.each { |r| through_association.target.delete(r) }
            else
              if through_records.include?(through_association.target)
                through_association.target = nil
              end
            end

            @through_records.delete(record)
          end
        end

        def find_target
          return [] unless target_reflection_has_associated_record?
          return scope.to_a if disable_joins
          super
        end

        # NOTE - not sure that we can actually cope with inverses here
        def invertible_for?(record)
          false
        end
    end
  end
end

has_one.rb

# frozen_string_literal: true

module ActiveRecord::Associations::Builder # :nodoc:
  class HasOne < SingularAssociation # :nodoc:
    def self.macro
      :has_one
    end

    def self.valid_options(options)
      valid = super
      valid += [:as, :foreign_type] if options[:as]
      valid += [:ensuring_owner_was] if options[:dependent] == :destroy_async
      valid += [:through, :source, :source_type] if options[:through]
      valid += [:disable_joins] if options[:disable_joins] && options[:through]
      valid
    end

    def self.valid_dependent_options
      [:destroy, :destroy_async, :delete, :nullify, :restrict_with_error, :restrict_with_exception]
    end

    def self.define_callbacks(model, reflection)
      super
      add_touch_callbacks(model, reflection) if reflection.options[:touch]
    end

    def self.add_destroy_callbacks(model, reflection)
      super unless reflection.options[:through]
    end

    def self.define_validations(model, reflection)
      super
      if reflection.options[:required]
        model.validates_presence_of reflection.name, message: :required
      end
    end

    def self.touch_record(record, name, touch)
      instance = record.send(name)

      if instance&.persisted?
        touch != true ?
          instance.touch(touch) : instance.touch
      end
    end

    def self.add_touch_callbacks(model, reflection)
      name  = reflection.name
      touch = reflection.options[:touch]

      callback = -> (record) { HasOne.touch_record(record, name, touch) }
      model.after_create callback, if: :saved_changes?
      model.after_create_commit { association(name).reset_negative_cache }
      model.after_update callback, if: :saved_changes?
      model.after_destroy callback
      model.after_touch callback
    end

    private_class_method :macro, :valid_options, :valid_dependent_options, :add_destroy_callbacks,
      :define_callbacks, :define_validations, :add_touch_callbacks
  end
end

has_one_association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    # = Active Record Has One Association
    class HasOneAssociation < SingularAssociation # :nodoc:
      include ForeignAssociation

      def handle_dependency
        case options[:dependent]
        when :restrict_with_exception
          raise ActiveRecord::DeleteRestrictionError.new(reflection.name) if load_target

        when :restrict_with_error
          if load_target
            record = owner.class.human_attribute_name(reflection.name).downcase
            owner.errors.add(:base, :'restrict_dependent_destroy.has_one', record: record)
            throw(:abort)
          end

        else
          delete
        end
      end

      def delete(method = options[:dependent])
        if load_target
          case method
          when :delete
            target.delete
          when :destroy
            target.destroyed_by_association = reflection
            target.destroy
            throw(:abort) unless target.destroyed?
          when :destroy_async
            primary_key_column = target.class.primary_key.to_sym
            id = target.public_send(primary_key_column)

            enqueue_destroy_association(
              owner_model_name: owner.class.to_s,
              owner_id: owner.id,
              association_class: reflection.klass.to_s,
              association_ids: [id],
              association_primary_key_column: primary_key_column,
              ensuring_owner_was_method: options.fetch(:ensuring_owner_was, nil)
            )
          when :nullify
            target.update_columns(nullified_owner_attributes) if target.persisted?
          end
        end
      end

      private
        def replace(record, save = true)
          raise_on_type_mismatch!(record) if record

          return target unless load_target || record

          assigning_another_record = target != record
          if assigning_another_record || record.has_changes_to_save?
            save &&= owner.persisted?

            transaction_if(save) do
              remove_target!(options[:dependent]) if target && !target.destroyed? && assigning_another_record

              if record
                set_owner_attributes(record)
                set_inverse_instance(record)

                if save && !record.save
                  nullify_owner_attributes(record)
                  set_owner_attributes(target) if target
                  raise RecordNotSaved.new("Failed to save the new associated #{reflection.name}.", record)
                end
              end
            end
          end

          self.target = record
        end

        # The reason that the save param for replace is false, if for create (not just build),
        # is because the setting of the foreign keys is actually handled by the scoping when
        # the record is instantiated, and so they are set straight away and do not need to be
        # updated within replace.
        def set_new_record(record)
          replace(record, false)
        end

        def remove_target!(method)
          case method
          when :delete
            target.delete
          when :destroy
            target.destroyed_by_association = reflection
            if target.persisted?
              target.destroy
            end
          else
            nullify_owner_attributes(target)
            remove_inverse_instance(target)

            if target.persisted? && owner.persisted? && !target.save
              set_owner_attributes(target)
              raise RecordNotSaved.new(
                "Failed to remove the existing associated #{reflection.name}. " \
                "The record failed to save after its foreign key was set to nil.",
                target
              )
            end
          end
        end

        def nullify_owner_attributes(record)
          record[reflection.foreign_key] = nil
        end

        def transaction_if(value, &block)
          if value
            reflection.klass.transaction(&block)
          else
            yield
          end
        end

        def _create_record(attributes, raise_error = false, &block)
          unless owner.persisted?
            raise ActiveRecord::RecordNotSaved.new("You cannot call create unless the parent is saved", owner)
          end

          super
        end
    end
  end
end

has_one_through_association.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    # = Active Record Has One Through Association
    class HasOneThroughAssociation < HasOneAssociation # :nodoc:
      include ThroughAssociation

      private
        def replace(record, save = true)
          create_through_record(record, save)
          self.target = record
        end

        def create_through_record(record, save)
          ensure_not_nested

          through_proxy  = through_association
          through_record = through_proxy.load_target

          if through_record && !record
            through_record.destroy
          elsif record
            attributes = construct_join_attributes(record)

            if through_record && through_record.destroyed?
              through_record = through_proxy.tap(&:reload).target
            end

            if through_record
              if through_record.new_record?
                through_record.assign_attributes(attributes)
              else
                through_record.update(attributes)
              end
            elsif owner.new_record? || !save
              through_proxy.build(attributes)
            else
              through_proxy.create(attributes)
            end
          end
        end
    end
  end
end

hash_config.rb

# frozen_string_literal: true

module ActiveRecord
  class DatabaseConfigurations
    # A HashConfig object is created for each database configuration entry that
    # is created from a hash.
    #
    # A hash config:
    #
    #   { "development" => { "database" => "db_name" } }
    #
    # Becomes:
    #
    #   #<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbded10
    #     @env_name="development", @name="primary", @config={database: "db_name"}>
    #
    # ==== Options
    #
    # * <tt>:env_name</tt> - The Rails environment, i.e. "development".
    # * <tt>:name</tt> - The db config name. In a standard two-tier
    #   database configuration this will default to "primary". In a multiple
    #   database three-tier database configuration this corresponds to the name
    #   used in the second tier, for example "primary_readonly".
    # * <tt>:config</tt> - The config hash. This is the hash that contains the
    #   database adapter, name, and other important information for database
    #   connections.
    class HashConfig < DatabaseConfig
      attr_reader :configuration_hash

      def initialize(env_name, name, configuration_hash)
        super(env_name, name)
        @configuration_hash = configuration_hash.symbolize_keys.freeze
      end

      # Determines whether a database configuration is for a replica / readonly
      # connection. If the +replica+ key is present in the config, +replica?+ will
      # return +true+.
      def replica?
        configuration_hash[:replica]
      end

      # The migrations paths for a database configuration. If the
      # +migrations_paths+ key is present in the config, +migrations_paths+
      # will return its value.
      def migrations_paths
        configuration_hash[:migrations_paths]
      end

      def host
        configuration_hash[:host]
      end

      def socket # :nodoc:
        configuration_hash[:socket]
      end

      def database
        configuration_hash[:database]
      end

      def _database=(database) # :nodoc:
        @configuration_hash = configuration_hash.merge(database: database).freeze
      end

      def pool
        (configuration_hash[:pool] || 5).to_i
      end

      def min_threads
        (configuration_hash[:min_threads] || 0).to_i
      end

      def max_threads
        (configuration_hash[:max_threads] || pool).to_i
      end

      def max_queue
        max_threads * 4
      end

      def checkout_timeout
        (configuration_hash[:checkout_timeout] || 5).to_f
      end

      # +reaping_frequency+ is configurable mostly for historical reasons, but it could
      # also be useful if someone wants a very low +idle_timeout+.
      def reaping_frequency
        configuration_hash.fetch(:reaping_frequency, 60)&.to_f
      end

      def idle_timeout
        timeout = configuration_hash.fetch(:idle_timeout, 300).to_f
        timeout if timeout > 0
      end

      def adapter
        configuration_hash[:adapter]
      end

      # The path to the schema cache dump file for a database.
      # If omitted, the filename will be read from ENV or a
      # default will be derived.
      def schema_cache_path
        configuration_hash[:schema_cache_path]
      end

      def default_schema_cache_path
        "db/schema_cache.yml"
      end

      def lazy_schema_cache_path
        schema_cache_path || default_schema_cache_path
      end

      def primary? # :nodoc:
        Base.configurations.primary?(name)
      end

      # Determines whether to dump the schema/structure files and the
      # filename that should be used.
      #
      # If +configuration_hash[:schema_dump]+ is set to +false+ or +nil+
      # the schema will not be dumped.
      #
      # If the config option is set that will be used. Otherwise Rails
      # will generate the filename from the database config name.
      def schema_dump(format = ActiveRecord.schema_format)
        if configuration_hash.key?(:schema_dump)
          if config = configuration_hash[:schema_dump]
            config
          end
        elsif primary?
          schema_file_type(format)
        else
          "#{name}_#{schema_file_type(format)}"
        end
      end

      def database_tasks? # :nodoc:
        !replica? && !!configuration_hash.fetch(:database_tasks, true)
      end

      private
        def schema_file_type(format)
          case format
          when :ruby
            "schema.rb"
          when :sql
            "structure.sql"
          end
        end
    end
  end
end

hash_lookup_type_map.rb

# frozen_string_literal: true

module ActiveRecord
  module Type
    class HashLookupTypeMap # :nodoc:
      def initialize(parent = nil)
        @mapping = {}
        @cache = Concurrent::Map.new do |h, key|
          h.fetch_or_store(key, Concurrent::Map.new)
        end
      end

      def lookup(lookup_key, *args)
        fetch(lookup_key, *args) { Type.default_value }
      end

      def fetch(lookup_key, *args, &block)
        @cache[lookup_key].fetch_or_store(args) do
          perform_fetch(lookup_key, *args, &block)
        end
      end

      def register_type(key, value = nil, &block)
        raise ::ArgumentError unless value || block

        if block
          @mapping[key] = block
        else
          @mapping[key] = proc { value }
        end
        @cache.clear
      end

      def clear
        @mapping.clear
        @cache.clear
      end

      def alias_type(type, alias_type)
        register_type(type) { |_, *args| lookup(alias_type, *args) }
      end

      def key?(key)
        @mapping.key?(key)
      end

      def keys
        @mapping.keys
      end

      private
        def perform_fetch(type, *args, &block)
          @mapping.fetch(type, block).call(type, *args)
        end
    end
  end
end

homogeneous_in.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class HomogeneousIn < Node
      attr_reader :attribute, :values, :type

      def initialize(values, attribute, type)
        @values = values
        @attribute = attribute
        @type = type
      end

      def hash
        ivars.hash
      end

      def eql?(other)
        super || (self.class == other.class && self.ivars == other.ivars)
      end
      alias :== :eql?

      def equality?
        type == :in
      end

      def invert
        Arel::Nodes::HomogeneousIn.new(values, attribute, type == :in ? :notin : :in)
      end

      def left
        attribute
      end

      def right
        attribute.quoted_array(values)
      end

      def table_name
        attribute.relation.table_alias || attribute.relation.name
      end

      def column_name
        attribute.name
      end

      def casted_values
        type = attribute.type_caster

        casted_values = values.map do |raw_value|
          type.serialize(raw_value) if type.serializable?(raw_value)
        end

        casted_values.compact!
        casted_values
      end

      def proc_for_binds
        -> value { ActiveModel::Attribute.with_cast_value(attribute.name, value, attribute.type_caster) }
      end

      def fetch_attribute(&block)
        if attribute
          yield attribute
        else
          expr.fetch_attribute(&block)
        end
      end

      protected
        def ivars
          [@attribute, @values, @type]
        end
    end
  end
end

hstore.rb

# frozen_string_literal: true

require "strscan"

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Hstore < Type::Value # :nodoc:
          ERROR = "Invalid Hstore document: %s"

          include ActiveModel::Type::Helpers::Mutable

          def type
            :hstore
          end

          def deserialize(value)
            return value unless value.is_a?(::String)

            scanner = StringScanner.new(value)
            hash = {}

            until scanner.eos?
              unless scanner.skip(/"/)
                raise(ArgumentError, ERROR % scanner.string.inspect)
              end

              unless key = scanner.scan_until(/(?<!\\)(?=")/)
                raise(ArgumentError, ERROR % scanner.string.inspect)
              end

              unless scanner.skip(/"=>?/)
                raise(ArgumentError, ERROR % scanner.string.inspect)
              end

              if scanner.scan(/NULL/)
                value = nil
              else
                unless scanner.skip(/"/)
                  raise(ArgumentError, ERROR % scanner.string.inspect)
                end

                unless value = scanner.scan_until(/(?<!\\)(?=")/)
                  raise(ArgumentError, ERROR % scanner.string.inspect)
                end

                unless scanner.skip(/"/)
                  raise(ArgumentError, ERROR % scanner.string.inspect)
                end
              end

              key.gsub!('\"', '"')
              key.gsub!("\\\\", "\\")

              if value
                value.gsub!('\"', '"')
                value.gsub!("\\\\", "\\")
              end

              hash[key] = value

              unless scanner.skip(/, /) || scanner.eos?
                raise(ArgumentError, ERROR % scanner.string.inspect)
              end
            end

            hash
          end

          def serialize(value)
            if value.is_a?(::Hash)
              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(", ")
            elsif value.respond_to?(:to_unsafe_h)
              serialize(value.to_unsafe_h)
            else
              value
            end
          end

          def accessor
            ActiveRecord::Store::StringKeyedHashAccessor
          end

          # Will compare the Hash equivalents of +raw_old_value+ and +new_value+.
          # By comparing hashes, this avoids an edge case where the order of
          # the keys change between the two hashes, and they would not be marked
          # as equal.
          def changed_in_place?(raw_old_value, new_value)
            deserialize(raw_old_value) != new_value
          end

          private
            def escape_hstore(value)
              if value.nil?
                "NULL"
              else
                if value == ""
                  '""'
                else
                  '"%s"' % value.to_s.gsub(/(["\\])/, '\\\\\1')
                end
              end
            end
        end
      end
    end
  end
end

in.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class In < Arel::Nodes::Binary
      include FetchAttribute

      def equality?; true; end

      def invert
        Arel::Nodes::NotIn.new(left, right)
      end
    end
  end
end

inet.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Inet < Cidr # :nodoc:
          def type
            :inet
          end
        end
      end
    end
  end
end

infix_operation.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class InfixOperation < Binary
      include Arel::Expressions
      include Arel::Predications
      include Arel::OrderPredications
      include Arel::AliasPredication
      include Arel::Math

      attr_reader :operator

      def initialize(operator, left, right)
        super(left, right)
        @operator = operator
      end
    end

    class Multiplication < InfixOperation
      def initialize(left, right)
        super(:*, left, right)
      end
    end

    class Division < InfixOperation
      def initialize(left, right)
        super(:/, left, right)
      end
    end

    class Addition < InfixOperation
      def initialize(left, right)
        super(:+, left, right)
      end
    end

    class Subtraction < InfixOperation
      def initialize(left, right)
        super(:-, left, right)
      end
    end

    class Concat < InfixOperation
      def initialize(left, right)
        super(:"||", left, right)
      end
    end

    class Contains < InfixOperation
      def initialize(left, right)
        super(:"@>", left, right)
      end
    end

    class Overlaps < InfixOperation
      def initialize(left, right)
        super(:"&&", left, right)
      end
    end

    class BitwiseAnd < InfixOperation
      def initialize(left, right)
        super(:&, left, right)
      end
    end

    class BitwiseOr < InfixOperation
      def initialize(left, right)
        super(:|, left, right)
      end
    end

    class BitwiseXor < InfixOperation
      def initialize(left, right)
        super(:^, left, right)
      end
    end

    class BitwiseShiftLeft < InfixOperation
      def initialize(left, right)
        super(:<<, left, right)
      end
    end

    class BitwiseShiftRight < InfixOperation
      def initialize(left, right)
        super(:>>, left, right)
      end
    end
  end
end

inheritance.rb

# frozen_string_literal: true

require "active_support/inflector"
require "active_support/core_ext/hash/indifferent_access"

module ActiveRecord
  # == Single table inheritance
  #
  # Active Record allows inheritance by storing the name of the class in a column that by
  # default is named "type" (can be changed by overwriting <tt>Base.inheritance_column</tt>).
  # This means that an inheritance looking like this:
  #
  #   class Company < ActiveRecord::Base; end
  #   class Firm < Company; end
  #   class Client < Company; end
  #   class PriorityClient < Client; end
  #
  # When you do <tt>Firm.create(name: "37signals")</tt>, this record will be saved in
  # the companies table with type = "Firm". You can then fetch this row again using
  # <tt>Company.where(name: '37signals').first</tt> and it will return a Firm object.
  #
  # Be aware that because the type column is an attribute on the record every new
  # subclass will instantly be marked as dirty and the type column will be included
  # in the list of changed attributes on the record. This is different from non
  # Single Table Inheritance(STI) classes:
  #
  #   Company.new.changed? # => false
  #   Firm.new.changed?    # => true
  #   Firm.new.changes     # => {"type"=>["","Firm"]}
  #
  # If you don't have a type column defined in your table, single-table inheritance won't
  # be triggered. In that case, it'll work just like normal subclasses with no special magic
  # for differentiating between them or reloading the right type with find.
  #
  # Note, all the attributes for all the cases are kept in the same table. Read more:
  # https://www.martinfowler.com/eaaCatalog/singleTableInheritance.html
  #
  module Inheritance
    extend ActiveSupport::Concern

    included do
      class_attribute :store_full_class_name, instance_writer: false, default: true

      # Determines whether to store the full constant name including namespace when using STI.
      # This is true, by default.
      class_attribute :store_full_sti_class, instance_writer: false, default: true

      set_base_class
    end

    module ClassMethods
      # Determines if one of the attributes passed in is the inheritance column,
      # and if the inheritance column is attr accessible, it initializes an
      # instance of the given subclass instead of the base class.
      def new(attributes = nil, &block)
        if abstract_class? || self == Base
          raise NotImplementedError, "#{self} is an abstract class and cannot be instantiated."
        end

        if _has_attribute?(inheritance_column)
          subclass = subclass_from_attributes(attributes)

          if subclass.nil? && scope_attributes = current_scope&.scope_for_create
            subclass = subclass_from_attributes(scope_attributes)
          end

          if subclass.nil? && base_class?
            subclass = subclass_from_attributes(column_defaults)
          end
        end

        if subclass && subclass != self
          subclass.new(attributes, &block)
        else
          super
        end
      end

      # Returns +true+ if this does not need STI type condition. Returns
      # +false+ if STI type condition needs to be applied.
      def descends_from_active_record?
        if self == Base
          false
        elsif superclass.abstract_class?
          superclass.descends_from_active_record?
        else
          superclass == Base || !columns_hash.include?(inheritance_column)
        end
      end

      def finder_needs_type_condition? # :nodoc:
        # This is like this because benchmarking justifies the strange :false stuff
        :true == (@finder_needs_type_condition ||= descends_from_active_record? ? :false : :true)
      end

      # Returns the class descending directly from ActiveRecord::Base, or
      # an abstract class, if any, in the inheritance hierarchy.
      #
      # If A extends ActiveRecord::Base, A.base_class will return A. If B descends from A
      # through some arbitrarily deep hierarchy, B.base_class will return A.
      #
      # If B < A and C < B and if A is an abstract_class then both B.base_class
      # and C.base_class would return B as the answer since A is an abstract_class.
      attr_reader :base_class

      # Returns whether the class is a base class.
      # See #base_class for more information.
      def base_class?
        base_class == self
      end

      # Set this to +true+ if this is an abstract class (see
      # <tt>abstract_class?</tt>).
      # If you are using inheritance with Active Record and don't want a class
      # to be considered as part of the STI hierarchy, you must set this to
      # true.
      # +ApplicationRecord+, for example, is generated as an abstract class.
      #
      # Consider the following default behaviour:
      #
      #   Shape = Class.new(ActiveRecord::Base)
      #   Polygon = Class.new(Shape)
      #   Square = Class.new(Polygon)
      #
      #   Shape.table_name   # => "shapes"
      #   Polygon.table_name # => "shapes"
      #   Square.table_name  # => "shapes"
      #   Shape.create!      # => #<Shape id: 1, type: nil>
      #   Polygon.create!    # => #<Polygon id: 2, type: "Polygon">
      #   Square.create!     # => #<Square id: 3, type: "Square">
      #
      # However, when using <tt>abstract_class</tt>, +Shape+ is omitted from
      # the hierarchy:
      #
      #   class Shape < ActiveRecord::Base
      #     self.abstract_class = true
      #   end
      #   Polygon = Class.new(Shape)
      #   Square = Class.new(Polygon)
      #
      #   Shape.table_name   # => nil
      #   Polygon.table_name # => "polygons"
      #   Square.table_name  # => "polygons"
      #   Shape.create!      # => NotImplementedError: Shape is an abstract class and cannot be instantiated.
      #   Polygon.create!    # => #<Polygon id: 1, type: nil>
      #   Square.create!     # => #<Square id: 2, type: "Square">
      #
      # Note that in the above example, to disallow the creation of a plain
      # +Polygon+, you should use <tt>validates :type, presence: true</tt>,
      # instead of setting it as an abstract class. This way, +Polygon+ will
      # stay in the hierarchy, and Active Record will continue to correctly
      # derive the table name.
      attr_accessor :abstract_class

      # Returns whether this class is an abstract class or not.
      def abstract_class?
        defined?(@abstract_class) && @abstract_class == true
      end

      # Sets the application record class for Active Record
      #
      # This is useful if your application uses a different class than
      # ApplicationRecord for your primary abstract class. This class
      # will share a database connection with Active Record. It is the class
      # that connects to your primary database.
      def primary_abstract_class
        if ActiveRecord.application_record_class && ActiveRecord.application_record_class.name != name
          raise ArgumentError, "The `primary_abstract_class` is already set to #{ActiveRecord.application_record_class.inspect}. There can only be one `primary_abstract_class` in an application."
        end

        self.abstract_class = true
        ActiveRecord.application_record_class = self
      end

      # Returns the value to be stored in the inheritance column for STI.
      def sti_name
        store_full_sti_class && store_full_class_name ? name : name.demodulize
      end

      # Returns the class for the provided +type_name+.
      #
      # It is used to find the class correspondent to the value stored in the inheritance column.
      def sti_class_for(type_name)
        if store_full_sti_class && store_full_class_name
          type_name.constantize
        else
          compute_type(type_name)
        end
      rescue NameError
        raise SubclassNotFound,
          "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " \
          "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " \
          "Please rename this column if you didn't intend it to be used for storing the inheritance class " \
          "or overwrite #{name}.inheritance_column to use another column for that information."
      end

      # Returns the value to be stored in the polymorphic type column for Polymorphic Associations.
      def polymorphic_name
        store_full_class_name ? base_class.name : base_class.name.demodulize
      end

      # Returns the class for the provided +name+.
      #
      # It is used to find the class correspondent to the value stored in the polymorphic type column.
      def polymorphic_class_for(name)
        if store_full_class_name
          name.constantize
        else
          compute_type(name)
        end
      end

      def inherited(subclass)
        subclass.set_base_class
        subclass.instance_variable_set(:@_type_candidates_cache, Concurrent::Map.new)
        super
      end

      def dup # :nodoc:
        # `initialize_dup` / `initialize_copy` don't work when defined
        # in the `singleton_class`.
        other = super
        other.set_base_class
        other
      end

      def initialize_clone(other) # :nodoc:
        super
        set_base_class
      end

      protected
        # Returns the class type of the record using the current module as a prefix. So descendants of
        # MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.
        def compute_type(type_name)
          if type_name.start_with?("::")
            # If the type is prefixed with a scope operator then we assume that
            # the type_name is an absolute reference.
            type_name.constantize
          else
            type_candidate = @_type_candidates_cache[type_name]
            if type_candidate && type_constant = type_candidate.safe_constantize
              return type_constant
            end

            # Build a list of candidates to search for
            candidates = []
            name.scan(/::|$/) { candidates.unshift "#{$`}::#{type_name}" }
            candidates << type_name

            candidates.each do |candidate|
              constant = candidate.safe_constantize
              if candidate == constant.to_s
                @_type_candidates_cache[type_name] = candidate
                return constant
              end
            end

            raise NameError.new("uninitialized constant #{candidates.first}", candidates.first)
          end
        end

        def set_base_class # :nodoc:
          @base_class = if self == Base
            self
          else
            unless self < Base
              raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
            end

            if superclass == Base || superclass.abstract_class?
              self
            else
              superclass.base_class
            end
          end
        end

      private
        # Called by +instantiate+ to decide which class to use for a new
        # record instance. For single-table inheritance, we check the record
        # for a +type+ column and return the corresponding class.
        def discriminate_class_for_record(record)
          if using_single_table_inheritance?(record)
            find_sti_class(record[inheritance_column])
          else
            super
          end
        end

        def using_single_table_inheritance?(record)
          record[inheritance_column].present? && _has_attribute?(inheritance_column)
        end

        def find_sti_class(type_name)
          type_name = base_class.type_for_attribute(inheritance_column).cast(type_name)
          subclass = sti_class_for(type_name)

          unless subclass == self || descendants.include?(subclass)
            raise SubclassNotFound, "Invalid single-table inheritance type: #{subclass.name} is not a subclass of #{name}"
          end

          subclass
        end

        def type_condition(table = arel_table)
          sti_column = table[inheritance_column]
          sti_names  = ([self] + descendants).map(&:sti_name)

          predicate_builder.build(sti_column, sti_names)
        end

        # Detect the subclass from the inheritance column of attrs. If the inheritance column value
        # is not self or a valid subclass, raises ActiveRecord::SubclassNotFound
        def subclass_from_attributes(attrs)
          attrs = attrs.to_h if attrs.respond_to?(:permitted?)
          if attrs.is_a?(Hash)
            subclass_name = attrs[inheritance_column] || attrs[inheritance_column.to_sym]

            if subclass_name.present?
              find_sti_class(subclass_name)
            end
          end
        end
    end

    def initialize_dup(other)
      super
      ensure_proper_type
    end

    private
      def initialize_internals_callback
        super
        ensure_proper_type
      end

      # Sets the attribute used for single table inheritance to this class name if this is not the
      # ActiveRecord::Base descendant.
      # Considering the hierarchy Reply < Message < ActiveRecord::Base, this makes it possible to
      # do Reply.new without having to set <tt>Reply[Reply.inheritance_column] = "Reply"</tt> yourself.
      # No such attribute would be set for objects of the Message class in that example.
      def ensure_proper_type
        klass = self.class
        if klass.finder_needs_type_condition?
          _write_attribute(klass.inheritance_column, klass.sti_name)
        end
      end
  end
end

inner_join.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class InnerJoin < Arel::Nodes::Join
    end
  end
end

insert_all.rb

# frozen_string_literal: true

require "active_support/core_ext/enumerable"

module ActiveRecord
  class InsertAll # :nodoc:
    attr_reader :model, :connection, :inserts, :keys
    attr_reader :on_duplicate, :update_only, :returning, :unique_by, :update_sql

    def initialize(model, inserts, on_duplicate:, update_only: nil, returning: nil, unique_by: nil, record_timestamps: nil)
      raise ArgumentError, "Empty list of attributes passed" if inserts.blank?

      @model, @connection, @inserts, @keys = model, model.connection, inserts, inserts.first.keys.map(&:to_s)
      @on_duplicate, @update_only, @returning, @unique_by = on_duplicate, update_only, returning, unique_by
      @record_timestamps = record_timestamps.nil? ? model.record_timestamps : record_timestamps

      disallow_raw_sql!(on_duplicate)
      disallow_raw_sql!(returning)

      configure_on_duplicate_update_logic

      if model.scope_attributes?
        @scope_attributes = model.scope_attributes
        @keys |= @scope_attributes.keys
      end
      @keys = @keys.to_set

      @returning = (connection.supports_insert_returning? ? primary_keys : false) if @returning.nil?
      @returning = false if @returning == []

      @unique_by = find_unique_index_for(unique_by)
      @on_duplicate = :skip if @on_duplicate == :update && updatable_columns.empty?

      ensure_valid_options_for_connection!
    end

    def execute
      message = +"#{model} "
      message << "Bulk " if inserts.many?
      message << (on_duplicate == :update ? "Upsert" : "Insert")
      connection.exec_insert_all to_sql, message
    end

    def updatable_columns
      @updatable_columns ||= keys - readonly_columns - unique_by_columns
    end

    def primary_keys
      Array(connection.schema_cache.primary_keys(model.table_name))
    end


    def skip_duplicates?
      on_duplicate == :skip
    end

    def update_duplicates?
      on_duplicate == :update
    end

    def map_key_with_value
      inserts.map do |attributes|
        attributes = attributes.stringify_keys
        attributes.merge!(scope_attributes) if scope_attributes
        attributes.reverse_merge!(timestamps_for_create) if record_timestamps?

        verify_attributes(attributes)

        keys_including_timestamps.map do |key|
          yield key, attributes[key]
        end
      end
    end

    def record_timestamps?
      @record_timestamps
    end

    # TODO: Consider renaming this method, as it only conditionally extends keys, not always
    def keys_including_timestamps
      @keys_including_timestamps ||= if record_timestamps?
        keys + model.all_timestamp_attributes_in_model
      else
        keys
      end
    end

    private
      attr_reader :scope_attributes

      def configure_on_duplicate_update_logic
        if custom_update_sql_provided? && update_only.present?
          raise ArgumentError, "You can't set :update_only and provide custom update SQL via :on_duplicate at the same time"
        end

        if update_only.present?
          @updatable_columns = Array(update_only)
          @on_duplicate = :update
        elsif custom_update_sql_provided?
          @update_sql = on_duplicate
          @on_duplicate = :update
        end
      end

      def custom_update_sql_provided?
        @custom_update_sql_provided ||= Arel.arel_node?(on_duplicate)
      end

      def find_unique_index_for(unique_by)
        if !connection.supports_insert_conflict_target?
          return if unique_by.nil?

          raise ArgumentError, "#{connection.class} does not support :unique_by"
        end

        name_or_columns = unique_by || model.primary_key
        match = Array(name_or_columns).map(&:to_s)

        if index = unique_indexes.find { |i| match.include?(i.name) || i.columns == match }
          index
        elsif match == primary_keys
          unique_by.nil? ? nil : ActiveRecord::ConnectionAdapters::IndexDefinition.new(model.table_name, "#{model.table_name}_primary_key", true, match)
        else
          raise ArgumentError, "No unique index found for #{name_or_columns}"
        end
      end

      def unique_indexes
        connection.schema_cache.indexes(model.table_name).select(&:unique)
      end


      def ensure_valid_options_for_connection!
        if returning && !connection.supports_insert_returning?
          raise ArgumentError, "#{connection.class} does not support :returning"
        end

        if skip_duplicates? && !connection.supports_insert_on_duplicate_skip?
          raise ArgumentError, "#{connection.class} does not support skipping duplicates"
        end

        if update_duplicates? && !connection.supports_insert_on_duplicate_update?
          raise ArgumentError, "#{connection.class} does not support upsert"
        end

        if unique_by && !connection.supports_insert_conflict_target?
          raise ArgumentError, "#{connection.class} does not support :unique_by"
        end
      end


      def to_sql
        connection.build_insert_sql(ActiveRecord::InsertAll::Builder.new(self))
      end


      def readonly_columns
        primary_keys + model.readonly_attributes.to_a
      end

      def unique_by_columns
        Array(unique_by&.columns)
      end


      def verify_attributes(attributes)
        if keys_including_timestamps != attributes.keys.to_set
          raise ArgumentError, "All objects being inserted must have the same keys"
        end
      end

      def disallow_raw_sql!(value)
        return if !value.is_a?(String) || Arel.arel_node?(value)

        raise ArgumentError, "Dangerous query method (method whose arguments are used as raw " \
                             "SQL) called: #{value}. " \
                             "Known-safe values can be passed " \
                             "by wrapping them in Arel.sql()."
      end

      def timestamps_for_create
        model.all_timestamp_attributes_in_model.index_with(connection.high_precision_current_timestamp)
      end

      class Builder # :nodoc:
        attr_reader :model

        delegate :skip_duplicates?, :update_duplicates?, :keys, :keys_including_timestamps, :record_timestamps?, to: :insert_all

        def initialize(insert_all)
          @insert_all, @model, @connection = insert_all, insert_all.model, insert_all.connection
        end

        def into
          "INTO #{model.quoted_table_name} (#{columns_list})"
        end

        def values_list
          types = extract_types_from_columns_on(model.table_name, keys: keys_including_timestamps)

          values_list = insert_all.map_key_with_value do |key, value|
            next value if Arel::Nodes::SqlLiteral === value
            connection.with_yaml_fallback(types[key].serialize(value))
          end

          connection.visitor.compile(Arel::Nodes::ValuesList.new(values_list))
        end

        def returning
          return unless insert_all.returning

          if insert_all.returning.is_a?(String)
            insert_all.returning
          else
            format_columns(insert_all.returning)
          end
        end

        def conflict_target
          if index = insert_all.unique_by
            sql = +"(#{format_columns(index.columns)})"
            sql << " WHERE #{index.where}" if index.where
            sql
          elsif update_duplicates?
            "(#{format_columns(insert_all.primary_keys)})"
          end
        end

        def updatable_columns
          quote_columns(insert_all.updatable_columns)
        end

        def touch_model_timestamps_unless(&block)
          return "" unless update_duplicates? && record_timestamps?

          model.timestamp_attributes_for_update_in_model.filter_map do |column_name|
            if touch_timestamp_attribute?(column_name)
              "#{column_name}=(CASE WHEN (#{updatable_columns.map(&block).join(" AND ")}) THEN #{model.quoted_table_name}.#{column_name} ELSE #{connection.high_precision_current_timestamp} END),"
            end
          end.join
        end

        def raw_update_sql
          insert_all.update_sql
        end

        alias raw_update_sql? raw_update_sql

        private
          attr_reader :connection, :insert_all

          def touch_timestamp_attribute?(column_name)
            insert_all.updatable_columns.exclude?(column_name)
          end

          def columns_list
            format_columns(insert_all.keys_including_timestamps)
          end

          def extract_types_from_columns_on(table_name, keys:)
            columns = connection.schema_cache.columns_hash(table_name)

            unknown_column = (keys - columns.keys).first
            raise UnknownAttributeError.new(model.new, unknown_column) if unknown_column

            keys.index_with { |key| model.type_for_attribute(key) }
          end

          def format_columns(columns)
            columns.respond_to?(:map) ? quote_columns(columns).join(",") : columns
          end

          def quote_columns(columns)
            columns.map(&connection.method(:quote_column_name))
          end
      end
  end
end

insert_manager.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  class InsertManager < Arel::TreeManager
    def initialize(table = nil)
      @ast = Nodes::InsertStatement.new(table)
    end

    def into(table)
      @ast.relation = table
      self
    end

    def columns; @ast.columns end
    def values=(val); @ast.values = val; end

    def select(select)
      @ast.select = select
    end

    def insert(fields)
      return if fields.empty?

      if String === fields
        @ast.values = Nodes::SqlLiteral.new(fields)
      else
        @ast.relation ||= fields.first.first.relation

        values = []

        fields.each do |column, value|
          @ast.columns << column
          values << value
        end
        @ast.values = create_values(values)
      end
      self
    end

    def create_values(values)
      Nodes::ValuesList.new([values])
    end

    def create_values_list(rows)
      Nodes::ValuesList.new(rows)
    end
  end
end

insert_statement.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class InsertStatement < Arel::Nodes::Node
      attr_accessor :relation, :columns, :values, :select

      def initialize(relation = nil)
        super()
        @relation = relation
        @columns  = []
        @values   = nil
        @select   = nil
      end

      def initialize_copy(other)
        super
        @columns = @columns.clone
        @values =  @values.clone if @values
        @select =  @select.clone if @select
      end

      def hash
        [@relation, @columns, @values, @select].hash
      end

      def eql?(other)
        self.class == other.class &&
          self.relation == other.relation &&
          self.columns == other.columns &&
          self.select == other.select &&
          self.values == other.values
      end
      alias :== :eql?
    end
  end
end

integration.rb

# frozen_string_literal: true

require "active_support/core_ext/string/filters"

module ActiveRecord
  module Integration
    extend ActiveSupport::Concern

    included do
      ##
      # :singleton-method:
      # Indicates the format used to generate the timestamp in the cache key, if
      # versioning is off. Accepts any of the symbols in <tt>Time::DATE_FORMATS</tt>.
      #
      # This is +:usec+, by default.
      class_attribute :cache_timestamp_format, instance_writer: false, default: :usec

      ##
      # :singleton-method:
      # Indicates whether to use a stable #cache_key method that is accompanied
      # by a changing version in the #cache_version method.
      #
      # This is +true+, by default on Rails 5.2 and above.
      class_attribute :cache_versioning, instance_writer: false, default: false

      ##
      # :singleton-method:
      # Indicates whether to use a stable #cache_key method that is accompanied
      # by a changing version in the #cache_version method on collections.
      #
      # This is +false+, by default until Rails 6.1.
      class_attribute :collection_cache_versioning, instance_writer: false, default: false
    end

    # Returns a +String+, which Action Pack uses for constructing a URL to this
    # object. The default implementation returns this record's id as a +String+,
    # or +nil+ if this record's unsaved.
    #
    # For example, suppose that you have a User model, and that you have a
    # <tt>resources :users</tt> route. Normally, +user_path+ will
    # construct a path with the user object's 'id' in it:
    #
    #   user = User.find_by(name: 'Phusion')
    #   user_path(user)  # => "/users/1"
    #
    # You can override +to_param+ in your model to make +user_path+ construct
    # a path using the user's name instead of the user's id:
    #
    #   class User < ActiveRecord::Base
    #     def to_param  # overridden
    #       name
    #     end
    #   end
    #
    #   user = User.find_by(name: 'Phusion')
    #   user_path(user)  # => "/users/Phusion"
    def to_param
      # We can't use alias_method here, because method 'id' optimizes itself on the fly.
      id && id.to_s # Be sure to stringify the id for routes
    end

    # Returns a stable cache key that can be used to identify this record.
    #
    #   Product.new.cache_key     # => "products/new"
    #   Product.find(5).cache_key # => "products/5"
    #
    # If ActiveRecord::Base.cache_versioning is turned off, as it was in Rails 5.1 and earlier,
    # the cache key will also include a version.
    #
    #   Product.cache_versioning = false
    #   Product.find(5).cache_key  # => "products/5-20071224150000" (updated_at available)
    def cache_key
      if new_record?
        "#{model_name.cache_key}/new"
      else
        if cache_version
          "#{model_name.cache_key}/#{id}"
        else
          timestamp = max_updated_column_timestamp

          if timestamp
            timestamp = timestamp.utc.to_fs(cache_timestamp_format)
            "#{model_name.cache_key}/#{id}-#{timestamp}"
          else
            "#{model_name.cache_key}/#{id}"
          end
        end
      end
    end

    # Returns a cache version that can be used together with the cache key to form
    # a recyclable caching scheme. By default, the #updated_at column is used for the
    # cache_version, but this method can be overwritten to return something else.
    #
    # Note, this method will return nil if ActiveRecord::Base.cache_versioning is set to
    # +false+.
    def cache_version
      return unless cache_versioning

      if has_attribute?("updated_at")
        timestamp = updated_at_before_type_cast
        if can_use_fast_cache_version?(timestamp)
          raw_timestamp_to_cache_version(timestamp)

        elsif timestamp = updated_at
          timestamp.utc.to_fs(cache_timestamp_format)
        end
      elsif self.class.has_attribute?("updated_at")
        raise ActiveModel::MissingAttributeError, "missing attribute: updated_at"
      end
    end

    # Returns a cache key along with the version.
    def cache_key_with_version
      if version = cache_version
        "#{cache_key}-#{version}"
      else
        cache_key
      end
    end

    module ClassMethods
      # Defines your model's +to_param+ method to generate "pretty" URLs
      # using +method_name+, which can be any attribute or method that
      # responds to +to_s+.
      #
      #   class User < ActiveRecord::Base
      #     to_param :name
      #   end
      #
      #   user = User.find_by(name: 'Fancy Pants')
      #   user.id         # => 123
      #   user_path(user) # => "/users/123-fancy-pants"
      #
      # Values longer than 20 characters will be truncated. The value
      # is truncated word by word.
      #
      #   user = User.find_by(name: 'David Heinemeier Hansson')
      #   user.id         # => 125
      #   user_path(user) # => "/users/125-david-heinemeier"
      #
      # Because the generated param begins with the record's +id+, it is
      # suitable for passing to +find+. In a controller, for example:
      #
      #   params[:id]               # => "123-fancy-pants"
      #   User.find(params[:id]).id # => 123
      def to_param(method_name = nil)
        if method_name.nil?
          super()
        else
          define_method :to_param do
            if (default = super()) &&
                 (result = send(method_name).to_s).present? &&
                   (param = result.squish.parameterize.truncate(20, separator: /-/, omission: "")).present?
              "#{default}-#{param}"
            else
              default
            end
          end
        end
      end

      def collection_cache_key(collection = all, timestamp_column = :updated_at) # :nodoc:
        collection.send(:compute_cache_key, timestamp_column)
      end
    end

    private
      # Detects if the value before type cast
      # can be used to generate a cache_version.
      #
      # The fast cache version only works with a
      # string value directly from the database.
      #
      # We also must check if the timestamp format has been changed
      # or if the timezone is not set to UTC then
      # we cannot apply our transformations correctly.
      def can_use_fast_cache_version?(timestamp)
        timestamp.is_a?(String) &&
          cache_timestamp_format == :usec &&
          self.class.connection.default_timezone == :utc &&
          !updated_at_came_from_user?
      end

      # Converts a raw database string to `:usec`
      # format.
      #
      # Example:
      #
      #   timestamp = "2018-10-15 20:02:15.266505"
      #   raw_timestamp_to_cache_version(timestamp)
      #   # => "20181015200215266505"
      #
      # PostgreSQL truncates trailing zeros,
      # https://github.com/postgres/postgres/commit/3e1beda2cde3495f41290e1ece5d544525810214
      # to account for this we pad the output with zeros
      def raw_timestamp_to_cache_version(timestamp)
        key = timestamp.delete("- :.")
        if key.length < 20
          key.ljust(20, "0")
        else
          key
        end
      end
  end
end

internal_metadata.rb

# frozen_string_literal: true

require "active_record/scoping/default"
require "active_record/scoping/named"

module ActiveRecord
  # This class is used to create a table that keeps track of values and keys such
  # as which environment migrations were run in.
  #
  # This is enabled by default. To disable this functionality set
  # `use_metadata_table` to false in your database configuration.
  class InternalMetadata < ActiveRecord::Base # :nodoc:
    self.record_timestamps = true

    class << self
      def enabled?
        ActiveRecord::Base.connection.use_metadata_table?
      end

      def primary_key
        "key"
      end

      def table_name
        "#{table_name_prefix}#{internal_metadata_table_name}#{table_name_suffix}"
      end

      def []=(key, value)
        return unless enabled?

        find_or_initialize_by(key: key).update!(value: value)
      end

      def [](key)
        return unless enabled?

        where(key: key).pick(:value)
      end

      # Creates an internal metadata table with columns +key+ and +value+
      def create_table
        return unless enabled?

        unless connection.table_exists?(table_name)
          connection.create_table(table_name, id: false) do |t|
            t.string :key, **connection.internal_string_options_for_primary_key
            t.string :value
            t.timestamps
          end
        end
      end

      def drop_table
        return unless enabled?

        connection.drop_table table_name, if_exists: true
      end
    end
  end
end

interval.rb

# frozen_string_literal: true

require "active_support/duration"

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Interval < Type::Value # :nodoc:
          def type
            :interval
          end

          def cast_value(value)
            case value
            when ::ActiveSupport::Duration
              value
            when ::String
              begin
                ::ActiveSupport::Duration.parse(value)
              rescue ::ActiveSupport::Duration::ISO8601Parser::ParsingError
                nil
              end
            else
              super
            end
          end

          def serialize(value)
            case value
            when ::ActiveSupport::Duration
              value.iso8601(precision: self.precision)
            when ::Numeric
              # Sometimes operations on Times returns just float number of seconds so we need to handle that.
              # Example: Time.current - (Time.current + 1.hour) # => -3600.000001776 (Float)
              value.seconds.iso8601(precision: self.precision)
            else
              super
            end
          end

          def type_cast_for_schema(value)
            serialize(value).inspect
          end
        end
      end
    end
  end
end

join_association.rb

# frozen_string_literal: true

require "active_record/associations/join_dependency/join_part"
require "active_support/core_ext/array/extract"

module ActiveRecord
  module Associations
    class JoinDependency # :nodoc:
      class JoinAssociation < JoinPart # :nodoc:
        attr_reader :reflection, :tables
        attr_accessor :table

        def initialize(reflection, children)
          super(reflection.klass, children)

          @reflection = reflection
        end

        def match?(other)
          return true if self == other
          super && reflection == other.reflection
        end

        def join_constraints(foreign_table, foreign_klass, join_type, alias_tracker)
          joins = []
          chain = []

          reflection.chain.each do |reflection|
            table, terminated = yield reflection
            @table ||= table

            if terminated
              foreign_table, foreign_klass = table, reflection.klass
              break
            end

            chain << [reflection, table]
          end

          # The chain starts with the target table, but we want to end with it here (makes
          # more sense in this context), so we reverse
          chain.reverse_each do |reflection, table|
            klass = reflection.klass

            scope = reflection.join_scope(table, foreign_table, foreign_klass)

            unless scope.references_values.empty?
              associations = scope.eager_load_values | scope.includes_values

              unless associations.empty?
                scope.joins! scope.construct_join_dependency(associations, Arel::Nodes::OuterJoin)
              end
            end

            arel = scope.arel(alias_tracker.aliases)
            nodes = arel.constraints.first

            if nodes.is_a?(Arel::Nodes::And)
              others = nodes.children.extract! do |node|
                !Arel.fetch_attribute(node) { |attr| attr.relation.name == table.name }
              end
            end

            joins << join_type.new(table, Arel::Nodes::On.new(nodes))

            if others && !others.empty?
              joins.concat arel.join_sources
              append_constraints(joins.last, others)
            end

            # The current table in this iteration becomes the foreign table in the next
            foreign_table, foreign_klass = table, klass
          end

          joins
        end

        def readonly?
          return @readonly if defined?(@readonly)

          @readonly = reflection.scope && reflection.scope_for(base_klass.unscoped).readonly_value
        end

        def strict_loading?
          return @strict_loading if defined?(@strict_loading)

          @strict_loading = reflection.scope && reflection.scope_for(base_klass.unscoped).strict_loading_value
        end

        private
          def append_constraints(join, constraints)
            if join.is_a?(Arel::Nodes::StringJoin)
              join_string = Arel::Nodes::And.new(constraints.unshift join.left)
              join.left = Arel.sql(base_klass.connection.visitor.compile(join_string))
            else
              right = join.right
              right.expr = Arel::Nodes::And.new(constraints.unshift right.expr)
            end
          end
      end
    end
  end
end

join_base.rb

# frozen_string_literal: true

require "active_record/associations/join_dependency/join_part"

module ActiveRecord
  module Associations
    class JoinDependency # :nodoc:
      class JoinBase < JoinPart # :nodoc:
        attr_reader :table

        def initialize(base_klass, table, children)
          super(base_klass, children)
          @table = table
        end

        def match?(other)
          return true if self == other
          super && base_klass == other.base_klass
        end
      end
    end
  end
end

join_dependency.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class JoinDependency # :nodoc:
      extend ActiveSupport::Autoload

      eager_autoload do
        autoload :JoinBase
        autoload :JoinAssociation
      end

      class Aliases # :nodoc:
        def initialize(tables)
          @tables = tables
          @alias_cache = tables.each_with_object({}) { |table, h|
            h[table.node] = table.columns.each_with_object({}) { |column, i|
              i[column.name] = column.alias
            }
          }
          @columns_cache = tables.each_with_object({}) { |table, h|
            h[table.node] = table.columns
          }
        end

        def columns
          @tables.flat_map(&:column_aliases)
        end

        def column_aliases(node)
          @columns_cache[node]
        end

        def column_alias(node, column)
          @alias_cache[node][column]
        end

        Table = Struct.new(:node, :columns) do # :nodoc:
          def column_aliases
            t = node.table
            columns.map { |column| t[column.name].as(column.alias) }
          end
        end
        Column = Struct.new(:name, :alias)
      end

      def self.make_tree(associations)
        hash = {}
        walk_tree associations, hash
        hash
      end

      def self.walk_tree(associations, hash)
        case associations
        when Symbol, String
          hash[associations.to_sym] ||= {}
        when Array
          associations.each do |assoc|
            walk_tree assoc, hash
          end
        when Hash
          associations.each do |k, v|
            cache = hash[k] ||= {}
            walk_tree v, cache
          end
        else
          raise ConfigurationError, associations.inspect
        end
      end

      def initialize(base, table, associations, join_type)
        tree = self.class.make_tree associations
        @join_root = JoinBase.new(base, table, build(tree, base))
        @join_type = join_type
      end

      def base_klass
        join_root.base_klass
      end

      def reflections
        join_root.drop(1).map!(&:reflection)
      end

      def join_constraints(joins_to_add, alias_tracker, references)
        @alias_tracker = alias_tracker
        @joined_tables = {}
        @references = {}

        references.each do |table_name|
          @references[table_name.to_sym] = table_name if table_name.is_a?(Arel::Nodes::SqlLiteral)
        end unless references.empty?

        joins = make_join_constraints(join_root, join_type)

        joins.concat joins_to_add.flat_map { |oj|
          if join_root.match? oj.join_root
            walk(join_root, oj.join_root, oj.join_type)
          else
            make_join_constraints(oj.join_root, oj.join_type)
          end
        }
      end

      def instantiate(result_set, strict_loading_value, &block)
        primary_key = aliases.column_alias(join_root, join_root.primary_key)

        seen = Hash.new { |i, parent|
          i[parent] = Hash.new { |j, child_class|
            j[child_class] = {}
          }
        }.compare_by_identity

        model_cache = Hash.new { |h, klass| h[klass] = {} }
        parents = model_cache[join_root]

        column_aliases = aliases.column_aliases(join_root)
        column_names = []

        result_set.columns.each do |name|
          column_names << name unless /\At\d+_r\d+\z/.match?(name)
        end

        if column_names.empty?
          column_types = {}
        else
          column_types = result_set.column_types
          unless column_types.empty?
            attribute_types = join_root.attribute_types
            column_types = column_types.slice(*column_names).delete_if { |k, _| attribute_types.key?(k) }
          end
          column_aliases += column_names.map! { |name| Aliases::Column.new(name, name) }
        end

        message_bus = ActiveSupport::Notifications.instrumenter

        payload = {
          record_count: result_set.length,
          class_name: join_root.base_klass.name
        }

        message_bus.instrument("instantiation.active_record", payload) do
          result_set.each { |row_hash|
            parent_key = primary_key ? row_hash[primary_key] : row_hash
            parent = parents[parent_key] ||= join_root.instantiate(row_hash, column_aliases, column_types, &block)
            construct(parent, join_root, row_hash, seen, model_cache, strict_loading_value)
          }
        end

        parents.values
      end

      def apply_column_aliases(relation)
        @join_root_alias = relation.select_values.empty?
        relation._select!(-> { aliases.columns })
      end

      def each(&block)
        join_root.each(&block)
      end

      protected
        attr_reader :join_root, :join_type

      private
        attr_reader :alias_tracker, :join_root_alias

        def aliases
          @aliases ||= Aliases.new join_root.each_with_index.map { |join_part, i|
            column_names = if join_part == join_root && !join_root_alias
              primary_key = join_root.primary_key
              primary_key ? [primary_key] : []
            else
              join_part.column_names
            end

            columns = column_names.each_with_index.map { |column_name, j|
              Aliases::Column.new column_name, "t#{i}_r#{j}"
            }
            Aliases::Table.new(join_part, columns)
          }
        end

        def make_join_constraints(join_root, join_type)
          join_root.children.flat_map do |child|
            make_constraints(join_root, child, join_type)
          end
        end

        def make_constraints(parent, child, join_type)
          foreign_table = parent.table
          foreign_klass = parent.base_klass
          child.join_constraints(foreign_table, foreign_klass, join_type, alias_tracker) do |reflection|
            table, terminated = @joined_tables[reflection]
            root = reflection == child.reflection

            if table && (!root || !terminated)
              @joined_tables[reflection] = [table, root] if root
              next table, true
            end

            table_name = @references[reflection.name.to_sym]&.to_s

            table = alias_tracker.aliased_table_for(reflection.klass.arel_table, table_name) do
              name = reflection.alias_candidate(parent.table_name)
              root ? name : "#{name}_join"
            end

            @joined_tables[reflection] ||= [table, root] if join_type == Arel::Nodes::OuterJoin
            table
          end.concat child.children.flat_map { |c| make_constraints(child, c, join_type) }
        end

        def walk(left, right, join_type)
          intersection, missing = right.children.map { |node1|
            [left.children.find { |node2| node1.match? node2 }, node1]
          }.partition(&:first)

          joins = intersection.flat_map { |l, r| r.table = l.table; walk(l, r, join_type) }
          joins.concat missing.flat_map { |_, n| make_constraints(left, n, join_type) }
        end

        def find_reflection(klass, name)
          klass._reflect_on_association(name) ||
            raise(ConfigurationError, "Can't join '#{klass.name}' to association named '#{name}'; perhaps you misspelled it?")
        end

        def build(associations, base_klass)
          associations.map do |name, right|
            reflection = find_reflection base_klass, name
            reflection.check_validity!
            reflection.check_eager_loadable!

            if reflection.polymorphic?
              raise EagerLoadPolymorphicError.new(reflection)
            end

            JoinAssociation.new(reflection, build(right, reflection.klass))
          end
        end

        def construct(ar_parent, parent, row, seen, model_cache, strict_loading_value)
          return if ar_parent.nil?

          parent.children.each do |node|
            if node.reflection.collection?
              other = ar_parent.association(node.reflection.name)
              other.loaded!
            elsif ar_parent.association_cached?(node.reflection.name)
              model = ar_parent.association(node.reflection.name).target
              construct(model, node, row, seen, model_cache, strict_loading_value)
              next
            end

            key = aliases.column_alias(node, node.primary_key)
            id = row[key]
            if id.nil?
              nil_association = ar_parent.association(node.reflection.name)
              nil_association.loaded!
              next
            end

            model = seen[ar_parent][node][id]

            if model
              construct(model, node, row, seen, model_cache, strict_loading_value)
            else
              model = construct_model(ar_parent, node, row, model_cache, id, strict_loading_value)

              seen[ar_parent][node][id] = model
              construct(model, node, row, seen, model_cache, strict_loading_value)
            end
          end
        end

        def construct_model(record, node, row, model_cache, id, strict_loading_value)
          other = record.association(node.reflection.name)

          model = model_cache[node][id] ||=
            node.instantiate(row, aliases.column_aliases(node)) do |m|
              m.strict_loading! if strict_loading_value
              other.set_inverse_instance(m)
            end

          if node.reflection.collection?
            other.target.push(model)
          else
            other.target = model
          end

          model.readonly! if node.readonly?
          model.strict_loading! if node.strict_loading?
          model
        end
    end
  end
end

join_part.rb

# frozen_string_literal: true

module ActiveRecord
  module Associations
    class JoinDependency # :nodoc:
      # A JoinPart represents a part of a JoinDependency. It is inherited
      # by JoinBase and JoinAssociation. A JoinBase represents the Active Record which
      # everything else is being joined onto. A JoinAssociation represents an association which
      # is joining to the base. A JoinAssociation may result in more than one actual join
      # operations (for example a has_and_belongs_to_many JoinAssociation would result in
      # two; one for the join table and one for the target table).
      class JoinPart # :nodoc:
        include Enumerable

        # The Active Record class which this join part is associated 'about'; for a JoinBase
        # this is the actual base model, for a JoinAssociation this is the target model of the
        # association.
        attr_reader :base_klass, :children

        delegate :table_name, :column_names, :primary_key, :attribute_types, to: :base_klass

        def initialize(base_klass, children)
          @base_klass = base_klass
          @children = children
        end

        def match?(other)
          self.class == other.class
        end

        def each(&block)
          yield self
          children.each { |child| child.each(&block) }
        end

        def each_children(&block)
          children.each do |child|
            yield self, child
            child.each_children(&block)
          end
        end

        # An Arel::Table for the active_record
        def table
          raise NotImplementedError
        end

        def extract_record(row, column_names_with_alias)
          # This code is performance critical as it is called per row.
          # see: https://github.com/rails/rails/pull/12185
          hash = {}

          index = 0
          length = column_names_with_alias.length

          while index < length
            column = column_names_with_alias[index]
            hash[column.name] = row[column.alias]
            index += 1
          end

          hash
        end

        def instantiate(row, aliases, column_types = {}, &block)
          base_klass.instantiate(extract_record(row, aliases), column_types, &block)
        end
      end
    end
  end
end

join_source.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    ###
    # Class that represents a join source
    #
    #   https://www.sqlite.org/syntaxdiagrams.html#join-source

    class JoinSource < Arel::Nodes::Binary
      def initialize(single_source, joinop = [])
        super
      end

      def empty?
        !left && right.empty?
      end
    end
  end
end

join_table.rb

# frozen_string_literal: true

module ActiveRecord
  class Migration
    module JoinTable # :nodoc:
      private
        def find_join_table_name(table_1, table_2, options = {})
          options.delete(:table_name) || join_table_name(table_1, table_2)
        end

        def join_table_name(table_1, table_2)
          ModelSchema.derive_join_table_name(table_1, table_2).to_sym
        end
    end
  end
end

json.rb

# frozen_string_literal: true

module ActiveRecord
  module Type
    class Json < ActiveModel::Type::Value
      include ActiveModel::Type::Helpers::Mutable

      def type
        :json
      end

      def deserialize(value)
        return value unless value.is_a?(::String)
        ActiveSupport::JSON.decode(value) rescue nil
      end

      def serialize(value)
        ActiveSupport::JSON.encode(value) unless value.nil?
      end

      def changed_in_place?(raw_old_value, new_value)
        deserialize(raw_old_value) != new_value
      end

      def accessor
        ActiveRecord::Store::StringKeyedHashAccessor
      end
    end
  end
end

jsonb.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Jsonb < Type::Json # :nodoc:
          def type
            :jsonb
          end
        end
      end
    end
  end
end

key.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # A key is a container for a given +secret+
    #
    # Optionally, it can include +public_tags+. These tags are meant to be stored
    # in clean (public) and can be used, for example, to include information that
    # references the key for a future retrieval operation.
    class Key
      attr_reader :secret, :public_tags

      def initialize(secret)
        @secret = secret
        @public_tags = Properties.new
      end

      def self.derive_from(password)
        secret = ActiveRecord::Encryption.key_generator.derive_key_from(password)
        ActiveRecord::Encryption::Key.new(secret)
      end

      def id
        Digest::SHA1.hexdigest(secret).first(4)
      end
    end
  end
end

key_generator.rb

# frozen_string_literal: true

require "securerandom"

module ActiveRecord
  module Encryption
    # Utility for generating and deriving random keys.
    class KeyGenerator
      # Returns a random key. The key will have a size in bytes of +:length+ (configured +Cipher+'s length by default)
      def generate_random_key(length: key_length)
        SecureRandom.random_bytes(length)
      end

      # Returns a random key in hexadecimal format. The key will have a size in bytes of +:length+ (configured +Cipher+'s
      # length by default)
      #
      # Hexadecimal format is handy for representing keys as printable text. To maximize the space of characters used, it is
      # good practice including not printable characters. Hexadecimal format ensures that generated keys are representable with
      # plain text
      #
      # To convert back to the original string with the desired length:
      #
      #   [ value ].pack("H*")
      def generate_random_hex_key(length: key_length)
        generate_random_key(length: length).unpack("H*")[0]
      end

      # Derives a key from the given password. The key will have a size in bytes of +:length+ (configured +Cipher+'s length
      # by default)
      #
      # The generated key will be salted with the value of +ActiveRecord::Encryption.key_derivation_salt+
      def derive_key_from(password, length: key_length)
        ActiveSupport::KeyGenerator.new(password).generate_key(key_derivation_salt, length)
      end

      private
        def key_derivation_salt
          @key_derivation_salt ||= ActiveRecord::Encryption.config.key_derivation_salt
        end

        def key_length
          @key_length ||= ActiveRecord::Encryption.cipher.key_length
        end
    end
  end
end

key_provider.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # A +KeyProvider+ serves keys:
    #
    # * An encryption key
    # * A list of potential decryption keys. Serving multiple decryption keys supports rotation-schemes
    #   where new keys are added but old keys need to continue working
    class KeyProvider
      def initialize(keys)
        @keys = Array(keys)
      end

      # Returns the first key in the list as the active key to perform encryptions
      #
      # When +ActiveRecord::Encryption.config.store_key_references+ is true, the key will include
      # a public tag referencing the key itself. That key will be stored in the public
      # headers of the encrypted message
      def encryption_key
        @encryption_key ||= @keys.last.tap do |key|
          key.public_tags.encrypted_data_key_id = key.id if ActiveRecord::Encryption.config.store_key_references
        end

        @encryption_key
      end

      # Returns the list of decryption keys
      #
      # When the message holds a reference to its encryption key, it will return an array
      # with that key. If not, it will return the list of keys.
      def decryption_keys(encrypted_message)
        if encrypted_message.headers.encrypted_data_key_id
          keys_grouped_by_id[encrypted_message.headers.encrypted_data_key_id]
        else
          @keys
        end
      end

      private
        def keys_grouped_by_id
          @keys_grouped_by_id ||= @keys.group_by(&:id)
        end
    end
  end
end

legacy_point.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class LegacyPoint < Type::Value # :nodoc:
          include ActiveModel::Type::Helpers::Mutable

          def type
            :point
          end

          def cast(value)
            case value
            when ::String
              if value.start_with?("(") && value.end_with?(")")
                value = value[1...-1]
              end
              cast(value.split(","))
            when ::Array
              value.map { |v| Float(v) }
            else
              value
            end
          end

          def serialize(value)
            if value.is_a?(::Array)
              "(#{number_for_point(value[0])},#{number_for_point(value[1])})"
            else
              super
            end
          end

          private
            def number_for_point(number)
              number.to_s.delete_suffix(".0")
            end
        end
      end
    end
  end
end

legacy_pool_manager.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    class LegacyPoolManager # :nodoc:
      def initialize
        @name_to_pool_config = {}
      end

      def shard_names
        @name_to_pool_config.keys
      end

      def pool_configs(_ = nil)
        @name_to_pool_config.values
      end

      def remove_pool_config(_, shard)
        @name_to_pool_config.delete(shard)
      end

      def get_pool_config(_, shard)
        @name_to_pool_config[shard]
      end

      def set_pool_config(role, shard, pool_config)
        if pool_config
          @name_to_pool_config[shard] = pool_config
        else
          raise ArgumentError, "The `pool_config` for the :#{role} role and :#{shard} shard was `nil`. Please check your configuration. If you want your writing role to be something other than `:writing` set `config.active_record.writing_role` in your application configuration. The same setting should be applied for the `reading_role` if applicable."
        end
      end
    end
  end
end

legacy_yaml_adapter.rb

# frozen_string_literal: true

module ActiveRecord
  module LegacyYamlAdapter # :nodoc:
    def self.convert(coder)
      return coder unless coder.is_a?(Psych::Coder)

      case coder["active_record_yaml_version"]
      when 1, 2 then coder
      else
        raise("Active Record doesn't know how to load YAML with this format.")
      end
    end
  end
end

length.rb

# frozen_string_literal: true

module ActiveRecord
  module Validations
    class LengthValidator < ActiveModel::Validations::LengthValidator # :nodoc:
      def validate_each(record, attribute, association_or_value)
        if association_or_value.respond_to?(:loaded?) && association_or_value.loaded?
          association_or_value = association_or_value.target.reject(&:marked_for_destruction?)
        end
        super
      end
    end

    module ClassMethods
      # Validates that the specified attributes match the length restrictions supplied.
      # If the attribute is an association, records that are marked for destruction are not counted.
      #
      # See ActiveModel::Validations::HelperMethods.validates_length_of for more information.
      def validates_length_of(*attr_names)
        validates_with LengthValidator, _merge_attributes(attr_names)
      end

      alias_method :validates_size_of, :validates_length_of
    end
  end
end

log_subscriber.rb

# frozen_string_literal: true

module ActiveRecord
  class LogSubscriber < ActiveSupport::LogSubscriber
    IGNORE_PAYLOAD_NAMES = ["SCHEMA", "EXPLAIN"]

    class_attribute :backtrace_cleaner, default: ActiveSupport::BacktraceCleaner.new

    def self.runtime=(value)
      ActiveRecord::RuntimeRegistry.sql_runtime = value
    end

    def self.runtime
      ActiveRecord::RuntimeRegistry.sql_runtime ||= 0
    end

    def self.reset_runtime
      rt, self.runtime = runtime, 0
      rt
    end

    def strict_loading_violation(event)
      debug do
        owner = event.payload[:owner]
        association = event.payload[:reflection].klass
        name = event.payload[:reflection].name

        color("Strict loading violation: #{owner} is marked for strict loading. The #{association} association named :#{name} cannot be lazily loaded.", RED)
      end
    end

    def sql(event)
      self.class.runtime += event.duration
      return unless logger.debug?

      payload = event.payload

      return if IGNORE_PAYLOAD_NAMES.include?(payload[:name])

      name = if payload[:async]
        "ASYNC #{payload[:name]} (#{payload[:lock_wait].round(1)}ms) (db time #{event.duration.round(1)}ms)"
      else
        "#{payload[:name]} (#{event.duration.round(1)}ms)"
      end
      name  = "CACHE #{name}" if payload[:cached]
      sql   = payload[:sql]
      binds = nil

      if payload[:binds]&.any?
        casted_params = type_casted_binds(payload[:type_casted_binds])

        binds = []
        payload[:binds].each_with_index do |attr, i|
          attribute_name = attr.respond_to?(:name) ? attr.name : attr[i].name
          filtered_params = filter(attribute_name, casted_params[i])

          binds << render_bind(attr, filtered_params)
        end
        binds = binds.inspect
        binds.prepend("  ")
      end

      name = colorize_payload_name(name, payload[:name])
      sql  = color(sql, sql_color(sql), true) if colorize_logging

      debug "  #{name}  #{sql}#{binds}"
    end

    private
      def type_casted_binds(casted_binds)
        casted_binds.respond_to?(:call) ? casted_binds.call : casted_binds
      end

      def render_bind(attr, value)
        case attr
        when ActiveModel::Attribute
          if attr.type.binary? && attr.value
            value = "<#{attr.value_for_database.to_s.bytesize} bytes of binary data>"
          end
        when Array
          attr = attr.first
        else
          attr = nil
        end

        [attr&.name, value]
      end

      def colorize_payload_name(name, payload_name)
        if payload_name.blank? || payload_name == "SQL" # SQL vs Model Load/Exists
          color(name, MAGENTA, true)
        else
          color(name, CYAN, true)
        end
      end

      def sql_color(sql)
        case sql
        when /\A\s*rollback/mi
          RED
        when /select .*for update/mi, /\A\s*lock/mi
          WHITE
        when /\A\s*select/i
          BLUE
        when /\A\s*insert/i
          GREEN
        when /\A\s*update/i
          YELLOW
        when /\A\s*delete/i
          RED
        when /transaction\s*\Z/i
          CYAN
        else
          MAGENTA
        end
      end

      def logger
        ActiveRecord::Base.logger
      end

      def debug(progname = nil, &block)
        return unless super

        if ActiveRecord.verbose_query_logs
          log_query_source
        end
      end

      def log_query_source
        source = extract_query_source_location(caller)

        if source
          logger.debug("  ↳ #{source}")
        end
      end

      def extract_query_source_location(locations)
        backtrace_cleaner.clean(locations.lazy).first
      end

      def filter(name, value)
        ActiveRecord::Base.inspection_filter.filter_param(name, value)
      end
  end
end

ActiveRecord::LogSubscriber.attach_to :active_record

macaddr.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Macaddr < Type::String # :nodoc:
          def type
            :macaddr
          end

          def changed?(old_value, new_value, _new_value_before_type_cast)
            old_value.class != new_value.class ||
              new_value && old_value.casecmp(new_value) != 0
          end

          def changed_in_place?(raw_old_value, new_value)
            raw_old_value.class != new_value.class ||
              new_value && raw_old_value.casecmp(new_value) != 0
          end
        end
      end
    end
  end
end

map.rb

# frozen_string_literal: true

module ActiveRecord
  module TypeCaster
    class Map # :nodoc:
      def initialize(klass)
        @klass = klass
      end

      def type_cast_for_database(attr_name, value)
        type = type_for_attribute(attr_name)
        type.serialize(value)
      end

      def type_for_attribute(name)
        klass.type_for_attribute(name)
      end

      private
        attr_reader :klass
    end
  end
end

matches.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class Matches < Binary
      attr_reader :escape
      attr_accessor :case_sensitive

      def initialize(left, right, escape = nil, case_sensitive = false)
        super(left, right)
        @escape = escape && Nodes.build_quoted(escape)
        @case_sensitive = case_sensitive
      end
    end

    class DoesNotMatch < Matches; end
  end
end

math.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Math
    def *(other)
      Arel::Nodes::Multiplication.new(self, other)
    end

    def +(other)
      Arel::Nodes::Grouping.new(Arel::Nodes::Addition.new(self, other))
    end

    def -(other)
      Arel::Nodes::Grouping.new(Arel::Nodes::Subtraction.new(self, other))
    end

    def /(other)
      Arel::Nodes::Division.new(self, other)
    end

    def &(other)
      Arel::Nodes::Grouping.new(Arel::Nodes::BitwiseAnd.new(self, other))
    end

    def |(other)
      Arel::Nodes::Grouping.new(Arel::Nodes::BitwiseOr.new(self, other))
    end

    def ^(other)
      Arel::Nodes::Grouping.new(Arel::Nodes::BitwiseXor.new(self, other))
    end

    def <<(other)
      Arel::Nodes::Grouping.new(Arel::Nodes::BitwiseShiftLeft.new(self, other))
    end

    def >>(other)
      Arel::Nodes::Grouping.new(Arel::Nodes::BitwiseShiftRight.new(self, other))
    end

    def ~@
      Arel::Nodes::BitwiseNot.new(self)
    end
  end
end

merger.rb

# frozen_string_literal: true

require "active_support/core_ext/hash/keys"

module ActiveRecord
  class Relation
    class HashMerger # :nodoc:
      attr_reader :relation, :hash

      def initialize(relation, hash, rewhere = nil)
        hash.assert_valid_keys(*Relation::VALUE_METHODS)

        @relation = relation
        @hash     = hash
        @rewhere  = rewhere
      end

      def merge
        Merger.new(relation, other, @rewhere).merge
      end

      # Applying values to a relation has some side effects. E.g.
      # interpolation might take place for where values. So we should
      # build a relation to merge in rather than directly merging
      # the values.
      def other
        other = Relation.create(
          relation.klass,
          table: relation.table,
          predicate_builder: relation.predicate_builder
        )
        hash.each do |k, v|
          k = :_select if k == :select
          if Array === v
            other.public_send("#{k}!", *v)
          else
            other.public_send("#{k}!", v)
          end
        end
        other
      end
    end

    class Merger # :nodoc:
      attr_reader :relation, :values, :other

      def initialize(relation, other, rewhere = nil)
        @relation = relation
        @values   = other.values
        @other    = other
        @rewhere  = rewhere
      end

      NORMAL_VALUES = Relation::VALUE_METHODS - Relation::CLAUSE_METHODS -
                      [
                        :select, :includes, :preload, :joins, :left_outer_joins,
                        :order, :reverse_order, :lock, :create_with, :reordering
                      ]

      def merge
        NORMAL_VALUES.each do |name|
          value = values[name]
          # The unless clause is here mostly for performance reasons (since the `send` call might be moderately
          # expensive), most of the time the value is going to be `nil` or `.blank?`, the only catch is that
          # `false.blank?` returns `true`, so there needs to be an extra check so that explicit `false` values
          # don't fall through the cracks.
          unless value.nil? || (value.blank? && false != value)
            relation.public_send(:"#{name}!", *value)
          end
        end

        merge_select_values
        merge_multi_values
        merge_single_values
        merge_clauses
        merge_preloads
        merge_joins
        merge_outer_joins

        relation
      end

      private
        def merge_select_values
          return if other.select_values.empty?

          if other.klass == relation.klass
            relation.select_values |= other.select_values
          else
            relation.select_values |= other.instance_eval do
              arel_columns(select_values)
            end
          end
        end

        def merge_preloads
          return if other.preload_values.empty? && other.includes_values.empty?

          if other.klass == relation.klass
            relation.preload_values |= other.preload_values unless other.preload_values.empty?
            relation.includes_values |= other.includes_values unless other.includes_values.empty?
          else
            reflection = relation.klass.reflect_on_all_associations.find do |r|
              r.class_name == other.klass.name
            end || return

            unless other.preload_values.empty?
              relation.preload! reflection.name => other.preload_values
            end

            unless other.includes_values.empty?
              relation.includes! reflection.name => other.includes_values
            end
          end
        end

        def merge_joins
          return if other.joins_values.empty?

          if other.klass == relation.klass
            relation.joins_values |= other.joins_values
          else
            associations, others = other.joins_values.partition do |join|
              case join
              when Hash, Symbol, Array; true
              end
            end

            join_dependency = other.construct_join_dependency(
              associations, Arel::Nodes::InnerJoin
            )
            relation.joins!(join_dependency, *others)
          end
        end

        def merge_outer_joins
          return if other.left_outer_joins_values.empty?

          if other.klass == relation.klass
            relation.left_outer_joins_values |= other.left_outer_joins_values
          else
            associations, others = other.left_outer_joins_values.partition do |join|
              case join
              when Hash, Symbol, Array; true
              end
            end

            join_dependency = other.construct_join_dependency(
              associations, Arel::Nodes::OuterJoin
            )
            relation.left_outer_joins!(join_dependency, *others)
          end
        end

        def merge_multi_values
          if other.reordering_value
            # override any order specified in the original relation
            relation.reorder!(*other.order_values)
          elsif other.order_values.any?
            # merge in order_values from relation
            relation.order!(*other.order_values)
          end

          extensions = other.extensions - relation.extensions
          relation.extending!(*extensions) if extensions.any?
        end

        def merge_single_values
          relation.lock_value ||= other.lock_value if other.lock_value

          unless other.create_with_value.blank?
            relation.create_with_value = (relation.create_with_value || {}).merge(other.create_with_value)
          end
        end

        def merge_clauses
          relation.from_clause = other.from_clause if replace_from_clause?

          where_clause = relation.where_clause.merge(other.where_clause, @rewhere)
          relation.where_clause = where_clause unless where_clause.empty?

          having_clause = relation.having_clause.merge(other.having_clause)
          relation.having_clause = having_clause unless having_clause.empty?
        end

        def replace_from_clause?
          relation.from_clause.empty? && !other.from_clause.empty? &&
            relation.klass.base_class == other.klass.base_class
        end
    end
  end
end

message.rb

# frozen_string_literal: true

module ActiveRecord
  module Encryption
    # A message defines the structure of the data we store in encrypted attributes. It contains:
    #
    # * An encrypted payload
    # * A list of unencrypted headers
    #
    # See +Encryptor#encrypt+
    class Message
      attr_accessor :payload, :headers

      def initialize(payload: nil, headers: {})
        validate_payload_type(payload)

        @payload = payload
        @headers = Properties.new(headers)
      end

      def ==(other_message)
        payload == other_message.payload && headers == other_message.headers
      end

      private
        def validate_payload_type(payload)
          unless payload.is_a?(String) || payload.nil?
            raise ActiveRecord::Encryption::Errors::ForbiddenClass, "Only string payloads allowed"
          end
        end
    end
  end
end

message_serializer.rb

# frozen_string_literal: true

require "base64"

module ActiveRecord
  module Encryption
    # A message serializer that serializes +Messages+ with JSON.
    #
    # The generated structure is pretty simple:
    #
    #   {
    #     p: <payload>,
    #     h: {
    #       header1: value1,
    #       header2: value2,
    #       ...
    #     }
    #   }
    #
    # Both the payload and the header values are encoded with Base64
    # to prevent JSON parsing errors and encoding issues when
    # storing the resulting serialized data.
    class MessageSerializer
      def load(serialized_content)
        data = JSON.parse(serialized_content)
        parse_message(data, 1)
      rescue JSON::ParserError
        raise ActiveRecord::Encryption::Errors::Encoding
      end

      def dump(message)
        raise ActiveRecord::Encryption::Errors::ForbiddenClass unless message.is_a?(ActiveRecord::Encryption::Message)
        JSON.dump message_to_json(message)
      end

      private
        def parse_message(data, level)
          validate_message_data_format(data, level)
          ActiveRecord::Encryption::Message.new(payload: decode_if_needed(data["p"]), headers: parse_properties(data["h"], level))
        end

        def validate_message_data_format(data, level)
          if level > 2
            raise ActiveRecord::Encryption::Errors::Decryption, "More than one level of hash nesting in headers is not supported"
          end

          unless data.is_a?(Hash) && data.has_key?("p")
            raise ActiveRecord::Encryption::Errors::Decryption, "Invalid data format: hash without payload"
          end
        end

        def parse_properties(headers, level)
          ActiveRecord::Encryption::Properties.new.tap do |properties|
            headers&.each do |key, value|
              properties[key] = value.is_a?(Hash) ? parse_message(value, level + 1) : decode_if_needed(value)
            end
          end
        end

        def message_to_json(message)
          {
            p: encode_if_needed(message.payload),
            h: headers_to_json(message.headers)
          }
        end

        def headers_to_json(headers)
          headers.transform_values do |value|
            value.is_a?(ActiveRecord::Encryption::Message) ? message_to_json(value) : encode_if_needed(value)
          end
        end

        def encode_if_needed(value)
          if value.is_a?(String)
            ::Base64.strict_encode64 value
          else
            value
          end
        end

        def decode_if_needed(value)
          if value.is_a?(String)
            ::Base64.strict_decode64(value)
          else
            value
          end
        rescue ArgumentError, TypeError
          raise Errors::Encoding
        end
    end
  end
end

migration.rb

# frozen_string_literal: true

require "rails/generators/migration"

module ActiveRecord
  module Generators # :nodoc:
    module Migration
      extend ActiveSupport::Concern
      include Rails::Generators::Migration

      module ClassMethods
        # Implement the required interface for Rails::Generators::Migration.
        def next_migration_number(dirname)
          next_migration_number = current_migration_number(dirname) + 1
          ActiveRecord::Migration.next_migration_number(next_migration_number)
        end
      end

      private
        def primary_key_type
          key_type = options[:primary_key_type]
          ", id: :#{key_type}" if key_type
        end

        def foreign_key_type
          key_type = options[:primary_key_type]
          ", type: :#{key_type}" if key_type
        end

        def db_migrate_path
          if defined?(Rails.application) && Rails.application
            configured_migrate_path || default_migrate_path
          else
            "db/migrate"
          end
        end

        def default_migrate_path
          Rails.application.config.paths["db/migrate"].to_ary.first
        end

        def configured_migrate_path
          return unless database = options[:database]
          config = ActiveRecord::Base.configurations.configs_for(
            env_name: Rails.env,
            name: database
          )
          config&.migrations_paths
        end
    end
  end
end

migration_generator.rb

# frozen_string_literal: true

require "rails/generators/active_record"

module ActiveRecord
  module Generators # :nodoc:
    class MigrationGenerator < Base # :nodoc:
      argument :attributes, type: :array, default: [], banner: "field[:type][:index] field[:type][:index]"

      class_option :timestamps, type: :boolean
      class_option :primary_key_type, type: :string, desc: "The type for primary key"
      class_option :database, type: :string, aliases: %i(--db), desc: "The database for your migration. By default, the current environment's primary database is used."

      def create_migration_file
        set_local_assigns!
        validate_file_name!
        migration_template @migration_template, File.join(db_migrate_path, "#{file_name}.rb")
      end

      private
        attr_reader :migration_action, :join_tables

        # Sets the default migration template that is being used for the generation of the migration.
        # Depending on command line arguments, the migration template and the table name instance
        # variables are set up.
        def set_local_assigns!
          @migration_template = "migration.rb"
          case file_name
          when /^(add)_.*_to_(.*)/, /^(remove)_.*?_from_(.*)/
            @migration_action = $1
            @table_name       = normalize_table_name($2)
          when /join_table/
            if attributes.length == 2
              @migration_action = "join"
              @join_tables      = pluralize_table_names? ? attributes.map(&:plural_name) : attributes.map(&:singular_name)

              set_index_names
            end
          when /^create_(.+)/
            @table_name = normalize_table_name($1)
            @migration_template = "create_table_migration.rb"
          end
        end

        def set_index_names
          attributes.each_with_index do |attr, i|
            attr.index_name = [attr, attributes[i - 1]].map { |a| index_name_for(a) }
          end
        end

        def index_name_for(attribute)
          if attribute.foreign_key?
            attribute.name
          else
            attribute.name.singularize.foreign_key
          end.to_sym
        end

        def attributes_with_index
          attributes.select { |a| !a.reference? && a.has_index? }
        end

        # A migration file name can only contain underscores (_), lowercase characters,
        # and numbers 0-9. Any other file name will raise an IllegalMigrationNameError.
        def validate_file_name!
          unless /^[_a-z0-9]+$/.match?(file_name)
            raise IllegalMigrationNameError.new(file_name)
          end
        end

        def normalize_table_name(_table_name)
          pluralize_table_names? ? _table_name.pluralize : _table_name.singularize
        end
    end
  end
end

model_generator.rb

# frozen_string_literal: true

require "rails/generators/active_record"

module ActiveRecord
  module Generators # :nodoc:
    class ModelGenerator < Base # :nodoc:
      argument :attributes, type: :array, default: [], banner: "field[:type][:index] field[:type][:index]"

      check_class_collision

      class_option :migration, type: :boolean
      class_option :timestamps, type: :boolean
      class_option :parent, type: :string, desc: "The parent class for the generated model"
      class_option :indexes, type: :boolean, default: true, desc: "Add indexes for references and belongs_to columns"
      class_option :primary_key_type, type: :string, desc: "The type for primary key"
      class_option :database, type: :string, aliases: %i(--db), desc: "The database for your model's migration. By default, the current environment's primary database is used."

      # creates the migration file for the model.
      def create_migration_file
        return if skip_migration_creation?
        attributes.each { |a| a.attr_options.delete(:index) if a.reference? && !a.has_index? } if options[:indexes] == false
        migration_template "../../migration/templates/create_table_migration.rb", File.join(db_migrate_path, "create_#{table_name}.rb")
      end

      def create_model_file
        generate_abstract_class if database && !parent
        template "model.rb", File.join("app/models", class_path, "#{file_name}.rb")
      end

      def create_module_file
        return if regular_class_path.empty?
        template "module.rb", File.join("app/models", "#{class_path.join('/')}.rb") if behavior == :invoke
      end

      hook_for :test_framework

      private
        # Skip creating migration file if:
        #   - options parent is present and database option is not present
        #   - migrations option is nil or false
        def skip_migration_creation?
          parent && !database || !migration
        end

        def attributes_with_index
          attributes.select { |a| !a.reference? && a.has_index? }
        end

        # Used by the migration template to determine the parent name of the model
        def parent_class_name
          if parent
            parent
          elsif database
            abstract_class_name
          else
            "ApplicationRecord"
          end
        end

        def generate_abstract_class
          path = File.join("app/models", "#{database.underscore}_record.rb")
          return if File.exist?(path)

          template "abstract_base_class.rb", path
        end

        def abstract_class_name
          "#{database.camelize}Record"
        end

        def database
          options[:database]
        end

        def parent
          options[:parent]
        end

        def migration
          options[:migration]
        end
    end
  end
end

model_metadata.rb

# frozen_string_literal: true

module ActiveRecord
  class FixtureSet
    class ModelMetadata # :nodoc:
      def initialize(model_class)
        @model_class = model_class
      end

      def primary_key_name
        @primary_key_name ||= @model_class && @model_class.primary_key
      end

      def primary_key_type
        @primary_key_type ||= @model_class && @model_class.type_for_attribute(@model_class.primary_key).type
      end

      def has_primary_key_column?
        @has_primary_key_column ||= primary_key_name &&
          @model_class.columns.any? { |col| col.name == primary_key_name }
      end

      def timestamp_column_names
        @model_class.all_timestamp_attributes_in_model
      end

      def inheritance_column_name
        @inheritance_column_name ||= @model_class && @model_class.inheritance_column
      end
    end
  end
end

model_schema.rb

# frozen_string_literal: true

require "monitor"

module ActiveRecord
  module ModelSchema
    extend ActiveSupport::Concern

    ##
    # :singleton-method: primary_key_prefix_type
    # :call-seq: primary_key_prefix_type
    #
    # The prefix type that will be prepended to every primary key column name.
    # The options are +:table_name+ and +:table_name_with_underscore+. If the first is specified,
    # the Product class will look for "productid" instead of "id" as the primary column. If the
    # latter is specified, the Product class will look for "product_id" instead of "id". Remember
    # that this is a global setting for all Active Records.

    ##
    # :singleton-method: primary_key_prefix_type=
    # :call-seq: primary_key_prefix_type=(prefix_type)
    #
    # Sets the prefix type that will be prepended to every primary key column name.
    # The options are +:table_name+ and +:table_name_with_underscore+. If the first is specified,
    # the Product class will look for "productid" instead of "id" as the primary column. If the
    # latter is specified, the Product class will look for "product_id" instead of "id". Remember
    # that this is a global setting for all Active Records.

    ##
    # :singleton-method: table_name_prefix
    # :call-seq: table_name_prefix
    #
    # The prefix string to prepend to every table name.

    ##
    # :singleton-method: table_name_prefix=
    # :call-seq: table_name_prefix=(prefix)
    #
    # Sets the prefix string to prepend to every table name. So if set to "basecamp_", all table
    # names will be named like "basecamp_projects", "basecamp_people", etc. This is a convenient
    # way of creating a namespace for tables in a shared database. By default, the prefix is the
    # empty string.
    #
    # If you are organising your models within modules you can add a prefix to the models within
    # a namespace by defining a singleton method in the parent module called table_name_prefix which
    # returns your chosen prefix.

    ##
    # :singleton-method: table_name_suffix
    # :call-seq: table_name_suffix
    #
    # The suffix string to append to every table name.

    ##
    # :singleton-method: table_name_suffix=
    # :call-seq: table_name_suffix=(suffix)
    #
    # Works like +table_name_prefix=+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp",
    # "people_basecamp"). By default, the suffix is the empty string.
    #
    # If you are organising your models within modules, you can add a suffix to the models within
    # a namespace by defining a singleton method in the parent module called table_name_suffix which
    # returns your chosen suffix.

    ##
    # :singleton-method: schema_migrations_table_name
    # :call-seq: schema_migrations_table_name
    #
    # The name of the schema migrations table. By default, the value is <tt>"schema_migrations"</tt>.

    ##
    # :singleton-method: schema_migrations_table_name=
    # :call-seq: schema_migrations_table_name=(table_name)
    #
    # Sets the name of the schema migrations table.

    ##
    # :singleton-method: internal_metadata_table_name
    # :call-seq: internal_metadata_table_name
    #
    # The name of the internal metadata table. By default, the value is <tt>"ar_internal_metadata"</tt>.

    ##
    # :singleton-method: internal_metadata_table_name=
    # :call-seq: internal_metadata_table_name=(table_name)
    #
    # Sets the name of the internal metadata table.

    ##
    # :singleton-method: pluralize_table_names
    # :call-seq: pluralize_table_names
    #
    # Indicates whether table names should be the pluralized versions of the corresponding class names.
    # If true, the default table name for a Product class will be "products". If false, it would just be "product".
    # See table_name for the full rules on table/class naming. This is true, by default.

    ##
    # :singleton-method: pluralize_table_names=
    # :call-seq: pluralize_table_names=(value)
    #
    # Set whether table names should be the pluralized versions of the corresponding class names.
    # If true, the default table name for a Product class will be "products". If false, it would just be "product".
    # See table_name for the full rules on table/class naming. This is true, by default.

    ##
    # :singleton-method: implicit_order_column
    # :call-seq: implicit_order_column
    #
    # The name of the column records are ordered by if no explicit order clause
    # is used during an ordered finder call. If not set the primary key is used.

    ##
    # :singleton-method: implicit_order_column=
    # :call-seq: implicit_order_column=(column_name)
    #
    # Sets the column to sort records by when no explicit order clause is used
    # during an ordered finder call. Useful when the primary key is not an
    # auto-incrementing integer, for example when it's a UUID. Records are subsorted
    # by the primary key if it exists to ensure deterministic results.

    ##
    # :singleton-method: immutable_strings_by_default=
    # :call-seq: immutable_strings_by_default=(bool)
    #
    # Determines whether columns should infer their type as +:string+ or
    # +:immutable_string+. This setting does not affect the behavior of
    # <tt>attribute :foo, :string</tt>. Defaults to false.

    included do
      class_attribute :primary_key_prefix_type, instance_writer: false
      class_attribute :table_name_prefix, instance_writer: false, default: ""
      class_attribute :table_name_suffix, instance_writer: false, default: ""
      class_attribute :schema_migrations_table_name, instance_accessor: false, default: "schema_migrations"
      class_attribute :internal_metadata_table_name, instance_accessor: false, default: "ar_internal_metadata"
      class_attribute :pluralize_table_names, instance_writer: false, default: true
      class_attribute :implicit_order_column, instance_accessor: false
      class_attribute :immutable_strings_by_default, instance_accessor: false

      # Defines the name of the table column which will store the class name on single-table
      # inheritance situations.
      #
      # The default inheritance column name is +type+, which means it's a
      # reserved word inside Active Record. To be able to use single-table
      # inheritance with another column name, or to use the column +type+ in
      # your own model for something else, you can set +inheritance_column+:
      #
      #     self.inheritance_column = 'zoink'
      class_attribute :inheritance_column, instance_accessor: false, default: "type"
      singleton_class.class_eval do
        alias_method :_inheritance_column=, :inheritance_column=
        private :_inheritance_column=
        alias_method :inheritance_column=, :real_inheritance_column=
      end

      self.protected_environments = ["production"]

      self.ignored_columns = [].freeze

      delegate :type_for_attribute, :column_for_attribute, to: :class

      initialize_load_schema_monitor
    end

    # Derives the join table name for +first_table+ and +second_table+. The
    # table names appear in alphabetical order. A common prefix is removed
    # (useful for namespaced models like Music::Artist and Music::Record):
    #
    #   artists, records => artists_records
    #   records, artists => artists_records
    #   music_artists, music_records => music_artists_records
    def self.derive_join_table_name(first_table, second_table) # :nodoc:
      [first_table.to_s, second_table.to_s].sort.join("\0").gsub(/^(.*_)(.+)\0\1(.+)/, '\1\2_\3').tr("\0", "_")
    end

    module ClassMethods
      # Guesses the table name (in forced lower-case) based on the name of the class in the
      # inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy
      # looks like: Reply < Message < ActiveRecord::Base, then Message is used
      # to guess the table name even when called on Reply. The rules used to do the guess
      # are handled by the Inflector class in Active Support, which knows almost all common
      # English inflections. You can add new inflections in config/initializers/inflections.rb.
      #
      # Nested classes are given table names prefixed by the singular form of
      # the parent's table name. Enclosing modules are not considered.
      #
      # ==== Examples
      #
      #   class Invoice < ActiveRecord::Base
      #   end
      #
      #   file                  class               table_name
      #   invoice.rb            Invoice             invoices
      #
      #   class Invoice < ActiveRecord::Base
      #     class Lineitem < ActiveRecord::Base
      #     end
      #   end
      #
      #   file                  class               table_name
      #   invoice.rb            Invoice::Lineitem   invoice_lineitems
      #
      #   module Invoice
      #     class Lineitem < ActiveRecord::Base
      #     end
      #   end
      #
      #   file                  class               table_name
      #   invoice/lineitem.rb   Invoice::Lineitem   lineitems
      #
      # Additionally, the class-level +table_name_prefix+ is prepended and the
      # +table_name_suffix+ is appended. So if you have "myapp_" as a prefix,
      # the table name guess for an Invoice class becomes "myapp_invoices".
      # Invoice::Lineitem becomes "myapp_invoice_lineitems".
      #
      # Active Model Naming's +model_name+ is the base name used to guess the
      # table name. In case a custom Active Model Name is defined, it will be
      # used for the table name as well:
      #
      #   class PostRecord < ActiveRecord::Base
      #     class << self
      #       def model_name
      #         ActiveModel::Name.new(self, nil, "Post")
      #       end
      #     end
      #   end
      #
      #   PostRecord.table_name
      #   # => "posts"
      #
      # You can also set your own table name explicitly:
      #
      #   class Mouse < ActiveRecord::Base
      #     self.table_name = "mice"
      #   end
      def table_name
        reset_table_name unless defined?(@table_name)
        @table_name
      end

      # Sets the table name explicitly. Example:
      #
      #   class Project < ActiveRecord::Base
      #     self.table_name = "project"
      #   end
      def table_name=(value)
        value = value && value.to_s

        if defined?(@table_name)
          return if value == @table_name
          reset_column_information if connected?
        end

        @table_name        = value
        @quoted_table_name = nil
        @arel_table        = nil
        @sequence_name     = nil unless defined?(@explicit_sequence_name) && @explicit_sequence_name
        @predicate_builder = nil
      end

      # Returns a quoted version of the table name, used to construct SQL statements.
      def quoted_table_name
        @quoted_table_name ||= connection.quote_table_name(table_name)
      end

      # Computes the table name, (re)sets it internally, and returns it.
      def reset_table_name # :nodoc:
        self.table_name = if abstract_class?
          superclass == Base ? nil : superclass.table_name
        elsif superclass.abstract_class?
          superclass.table_name || compute_table_name
        else
          compute_table_name
        end
      end

      def full_table_name_prefix # :nodoc:
        (module_parents.detect { |p| p.respond_to?(:table_name_prefix) } || self).table_name_prefix
      end

      def full_table_name_suffix # :nodoc:
        (module_parents.detect { |p| p.respond_to?(:table_name_suffix) } || self).table_name_suffix
      end

      # The array of names of environments where destructive actions should be prohibited. By default,
      # the value is <tt>["production"]</tt>.
      def protected_environments
        if defined?(@protected_environments)
          @protected_environments
        else
          superclass.protected_environments
        end
      end

      # Sets an array of names of environments where destructive actions should be prohibited.
      def protected_environments=(environments)
        @protected_environments = environments.map(&:to_s)
      end

      def real_inheritance_column=(value) # :nodoc:
        self._inheritance_column = value.to_s
      end

      # The list of columns names the model should ignore. Ignored columns won't have attribute
      # accessors defined, and won't be referenced in SQL queries.
      def ignored_columns
        if defined?(@ignored_columns)
          @ignored_columns
        else
          superclass.ignored_columns
        end
      end

      # Sets the columns names the model should ignore. Ignored columns won't have attribute
      # accessors defined, and won't be referenced in SQL queries.
      #
      # A common usage pattern for this method is to ensure all references to an attribute
      # have been removed and deployed, before a migration to drop the column from the database
      # has been deployed and run. Using this two step approach to dropping columns ensures there
      # is no code that raises errors due to having a cached schema in memory at the time the
      # schema migration is run.
      #
      # For example, given a model where you want to drop the "category" attribute, first mark it
      # as ignored:
      #
      #   class Project < ActiveRecord::Base
      #     # schema:
      #     #   id         :bigint
      #     #   name       :string, limit: 255
      #     #   category   :string, limit: 255
      #
      #     self.ignored_columns = [:category]
      #   end
      #
      # The schema still contains "category", but now the model omits it, so any meta-driven code or
      # schema caching will not attempt to use the column:
      #
      #   Project.columns_hash["category"] => nil
      #
      # You will get an error if accessing that attribute directly, so ensure all usages of the
      # column are removed (automated tests can help you find any usages).
      #
      #   user = Project.create!(name: "First Project")
      #   user.category # => raises NoMethodError
      def ignored_columns=(columns)
        reload_schema_from_cache
        @ignored_columns = columns.map(&:to_s).freeze
      end

      def sequence_name
        if base_class?
          @sequence_name ||= reset_sequence_name
        else
          (@sequence_name ||= nil) || base_class.sequence_name
        end
      end

      def reset_sequence_name # :nodoc:
        @explicit_sequence_name = false
        @sequence_name          = connection.default_sequence_name(table_name, primary_key)
      end

      # Sets the name of the sequence to use when generating ids to the given
      # value, or (if the value is +nil+ or +false+) to the value returned by the
      # given block. This is required for Oracle and is useful for any
      # database which relies on sequences for primary key generation.
      #
      # If a sequence name is not explicitly set when using Oracle,
      # it will default to the commonly used pattern of: #{table_name}_seq
      #
      # If a sequence name is not explicitly set when using PostgreSQL, it
      # will discover the sequence corresponding to your primary key for you.
      #
      #   class Project < ActiveRecord::Base
      #     self.sequence_name = "projectseq"   # default would have been "project_seq"
      #   end
      def sequence_name=(value)
        @sequence_name          = value.to_s
        @explicit_sequence_name = true
      end

      # Determines if the primary key values should be selected from their
      # corresponding sequence before the insert statement.
      def prefetch_primary_key?
        connection.prefetch_primary_key?(table_name)
      end

      # Returns the next value that will be used as the primary key on
      # an insert statement.
      def next_sequence_value
        connection.next_sequence_value(sequence_name)
      end

      # Indicates whether the table associated with this class exists
      def table_exists?
        connection.schema_cache.data_source_exists?(table_name)
      end

      def attributes_builder # :nodoc:
        unless defined?(@attributes_builder) && @attributes_builder
          defaults = _default_attributes.except(*(column_names - [primary_key]))
          @attributes_builder = ActiveModel::AttributeSet::Builder.new(attribute_types, defaults)
        end
        @attributes_builder
      end

      def columns_hash # :nodoc:
        load_schema
        @columns_hash
      end

      def columns
        load_schema
        @columns ||= columns_hash.values.freeze
      end

      def attribute_types # :nodoc:
        load_schema
        @attribute_types ||= Hash.new(Type.default_value)
      end

      def yaml_encoder # :nodoc:
        @yaml_encoder ||= ActiveModel::AttributeSet::YAMLEncoder.new(attribute_types)
      end

      # Returns the type of the attribute with the given name, after applying
      # all modifiers. This method is the only valid source of information for
      # anything related to the types of a model's attributes. This method will
      # access the database and load the model's schema if it is required.
      #
      # The return value of this method will implement the interface described
      # by ActiveModel::Type::Value (though the object itself may not subclass
      # it).
      #
      # +attr_name+ The name of the attribute to retrieve the type for. Must be
      # a string or a symbol.
      def type_for_attribute(attr_name, &block)
        attr_name = attr_name.to_s
        attr_name = attribute_aliases[attr_name] || attr_name

        if block
          attribute_types.fetch(attr_name, &block)
        else
          attribute_types[attr_name]
        end
      end

      # Returns the column object for the named attribute.
      # Returns an +ActiveRecord::ConnectionAdapters::NullColumn+ if the
      # named attribute does not exist.
      #
      #   class Person < ActiveRecord::Base
      #   end
      #
      #   person = Person.new
      #   person.column_for_attribute(:name) # the result depends on the ConnectionAdapter
      #   # => #<ActiveRecord::ConnectionAdapters::Column:0x007ff4ab083980 @name="name", @sql_type="varchar(255)", @null=true, ...>
      #
      #   person.column_for_attribute(:nothing)
      #   # => #<ActiveRecord::ConnectionAdapters::NullColumn:0xXXX @name=nil, @sql_type=nil, @cast_type=#<Type::Value>, ...>
      def column_for_attribute(name)
        name = name.to_s
        columns_hash.fetch(name) do
          ConnectionAdapters::NullColumn.new(name)
        end
      end

      # Returns a hash where the keys are column names and the values are
      # default values when instantiating the Active Record object for this table.
      def column_defaults
        load_schema
        @column_defaults ||= _default_attributes.deep_dup.to_hash.freeze
      end

      def _default_attributes # :nodoc:
        load_schema
        @default_attributes ||= ActiveModel::AttributeSet.new({})
      end

      # Returns an array of column names as strings.
      def column_names
        @column_names ||= columns.map(&:name).freeze
      end

      def symbol_column_to_string(name_symbol) # :nodoc:
        @symbol_column_to_string_name_hash ||= column_names.index_by(&:to_sym)
        @symbol_column_to_string_name_hash[name_symbol]
      end

      # Returns an array of column objects where the primary id, all columns ending in "_id" or "_count",
      # and columns used for single table inheritance have been removed.
      def content_columns
        @content_columns ||= columns.reject do |c|
          c.name == primary_key ||
          c.name == inheritance_column ||
          c.name.end_with?("_id", "_count")
        end.freeze
      end

      # Resets all the cached information about columns, which will cause them
      # to be reloaded on the next request.
      #
      # The most common usage pattern for this method is probably in a migration,
      # when just after creating a table you want to populate it with some default
      # values, e.g.:
      #
      #  class CreateJobLevels < ActiveRecord::Migration[7.1]
      #    def up
      #      create_table :job_levels do |t|
      #        t.integer :id
      #        t.string :name
      #
      #        t.timestamps
      #      end
      #
      #      JobLevel.reset_column_information
      #      %w{assistant executive manager director}.each do |type|
      #        JobLevel.create(name: type)
      #      end
      #    end
      #
      #    def down
      #      drop_table :job_levels
      #    end
      #  end
      def reset_column_information
        connection.clear_cache!
        ([self] + descendants).each(&:undefine_attribute_methods)
        connection.schema_cache.clear_data_source_cache!(table_name)

        reload_schema_from_cache
        initialize_find_by_cache
      end

      protected
        def initialize_load_schema_monitor
          @load_schema_monitor = Monitor.new
        end

      private
        def inherited(child_class)
          super
          child_class.initialize_load_schema_monitor
        end

        def schema_loaded?
          defined?(@schema_loaded) && @schema_loaded
        end

        def load_schema
          return if schema_loaded?
          @load_schema_monitor.synchronize do
            return if defined?(@columns_hash) && @columns_hash

            load_schema!

            @schema_loaded = true
          rescue
            reload_schema_from_cache # If the schema loading failed half way through, we must reset the state.
            raise
          end
        end

        def load_schema!
          unless table_name
            raise ActiveRecord::TableNotSpecified, "#{self} has no table configured. Set one with #{self}.table_name="
          end

          columns_hash = connection.schema_cache.columns_hash(table_name)
          columns_hash = columns_hash.except(*ignored_columns) unless ignored_columns.empty?
          @columns_hash = columns_hash.freeze
          @columns_hash.each do |name, column|
            type = connection.lookup_cast_type_from_column(column)
            type = _convert_type_from_options(type)
            define_attribute(
              name,
              type,
              default: column.default,
              user_provided_default: false
            )
          end
        end

        def reload_schema_from_cache
          @arel_table = nil
          @column_names = nil
          @symbol_column_to_string_name_hash = nil
          @attribute_types = nil
          @content_columns = nil
          @default_attributes = nil
          @column_defaults = nil
          @attributes_builder = nil
          @columns = nil
          @columns_hash = nil
          @schema_loaded = false
          @attribute_names = nil
          @yaml_encoder = nil
          subclasses.each do |descendant|
            descendant.send(:reload_schema_from_cache)
          end
        end

        # Guesses the table name, but does not decorate it with prefix and suffix information.
        def undecorated_table_name(model_name)
          table_name = model_name.to_s.demodulize.underscore
          pluralize_table_names ? table_name.pluralize : table_name
        end

        # Computes and returns a table name according to default conventions.
        def compute_table_name
          if base_class?
            # Nested classes are prefixed with singular parent table name.
            if module_parent < Base && !module_parent.abstract_class?
              contained = module_parent.table_name
              contained = contained.singularize if module_parent.pluralize_table_names
              contained += "_"
            end

            "#{full_table_name_prefix}#{contained}#{undecorated_table_name(model_name)}#{full_table_name_suffix}"
          else
            # STI subclasses always use their superclass's table.
            base_class.table_name
          end
        end

        def _convert_type_from_options(type)
          if immutable_strings_by_default && type.respond_to?(:to_immutable_string)
            type.to_immutable_string
          else
            type
          end
        end
    end
  end
end

money.rb

# frozen_string_literal: true

module ActiveRecord
  module ConnectionAdapters
    module PostgreSQL
      module OID # :nodoc:
        class Money < Type::Decimal # :nodoc:
          def type
            :money
          end

          def scale
            2
          end

          def cast_value(value)
            return value unless ::String === value

            # Because money output is formatted according to the locale, there are two
            # cases to consider (note the decimal separators):
            #  (1) $12,345,678.12
            #  (2) $12.345.678,12
            # Negative values are represented as follows:
            #  (3) -$2.55
            #  (4) ($2.55)

            value = value.sub(/^\((.+)\)$/, '-\1') # (4)
            case value
            when /^-?\D*+[\d,]+\.\d{2}$/  # (1)
              value.gsub!(/[^-\d.]/, "")
            when /^-?\D*+[\d.]+,\d{2}$/  # (2)
              value.gsub!(/[^-\d,]/, "").sub!(/,/, ".")
            end

            super(value)
          end
        end
      end
    end
  end
end

multi_db_generator.rb

# frozen_string_literal: true

require "rails/generators/active_record"

module ActiveRecord
  module Generators # :nodoc:
    class MultiDbGenerator < ::Rails::Generators::Base # :nodoc:
      source_root File.expand_path("templates", __dir__)

      def create_multi_db
        filename = "multi_db.rb"
        template filename, "config/initializers/#{filename}"
      end
    end
  end
end

mysql.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Visitors
    class MySQL < Arel::Visitors::ToSql
      private
        def visit_Arel_Nodes_Bin(o, collector)
          collector << "BINARY "
          visit o.expr, collector
        end

        def visit_Arel_Nodes_UnqualifiedColumn(o, collector)
          visit o.expr, collector
        end

        ###
        # :'(
        # To retrieve all rows from a certain offset up to the end of the result set,
        # you can use some large number for the second parameter.
        # https://dev.mysql.com/doc/refman/en/select.html
        def visit_Arel_Nodes_SelectStatement(o, collector)
          if o.offset && !o.limit
            o.limit = Arel::Nodes::Limit.new(18446744073709551615)
          end
          super
        end

        def visit_Arel_Nodes_SelectCore(o, collector)
          o.froms ||= Arel.sql("DUAL")
          super
        end

        def visit_Arel_Nodes_Concat(o, collector)
          collector << " CONCAT("
          visit o.left, collector
          collector << ", "
          visit o.right, collector
          collector << ") "
          collector
        end

        def visit_Arel_Nodes_IsNotDistinctFrom(o, collector)
          collector = visit o.left, collector
          collector << " <=> "
          visit o.right, collector
        end

        def visit_Arel_Nodes_IsDistinctFrom(o, collector)
          collector << "NOT "
          visit_Arel_Nodes_IsNotDistinctFrom o, collector
        end

        def visit_Arel_Nodes_Regexp(o, collector)
          infix_value o, collector, " REGEXP "
        end

        def visit_Arel_Nodes_NotRegexp(o, collector)
          infix_value o, collector, " NOT REGEXP "
        end

        # no-op
        def visit_Arel_Nodes_NullsFirst(o, collector)
          visit o.expr, collector
        end

        # In the simple case, MySQL allows us to place JOINs directly into the UPDATE
        # query. However, this does not allow for LIMIT, OFFSET and ORDER. To support
        # these, we must use a subquery.
        def prepare_update_statement(o)
          if o.offset || has_group_by_and_having?(o) ||
            has_join_sources?(o) && has_limit_or_offset_or_orders?(o)
            super
          else
            o
          end
        end
        alias :prepare_delete_statement :prepare_update_statement

        # MySQL doesn't automatically create a temporary table for use subquery, so we have
        # to give it some prompting in the form of a subsubquery.
        def build_subselect(key, o)
          subselect = super

          # Materialize subquery by adding distinct
          # to work with MySQL 5.7.6 which sets optimizer_switch='derived_merge=on'
          unless has_limit_or_offset_or_orders?(subselect)
            core = subselect.cores.last
            core.set_quantifier = Arel::Nodes::Distinct.new
          end

          Nodes::SelectStatement.new.tap do |stmt|
            core = stmt.cores.last
            core.froms = Nodes::Grouping.new(subselect).as("__active_record_temp")
            core.projections = [Arel.sql(quote_column_name(key.name))]
          end
        end
    end
  end
end

mysql2_adapter.rb

# frozen_string_literal: true

require "active_record/connection_adapters/abstract_mysql_adapter"
require "active_record/connection_adapters/mysql/database_statements"

gem "mysql2", "~> 0.5"
require "mysql2"

module ActiveRecord
  module ConnectionHandling # :nodoc:
    # Establishes a connection to the database that's used by all Active Record objects.
    def mysql2_connection(config)
      config = config.symbolize_keys
      config[:flags] ||= 0

      if config[:flags].kind_of? Array
        config[:flags].push "FOUND_ROWS"
      else
        config[:flags] |= Mysql2::Client::FOUND_ROWS
      end

      ConnectionAdapters::Mysql2Adapter.new(
        ConnectionAdapters::Mysql2Adapter.new_client(config),
        logger,
        nil,
        config,
      )
    end
  end

  module ConnectionAdapters
    class Mysql2Adapter < AbstractMysqlAdapter
      ER_BAD_DB_ERROR        = 1049
      ER_ACCESS_DENIED_ERROR = 1045
      ER_CONN_HOST_ERROR     = 2003
      ER_UNKNOWN_HOST_ERROR  = 2005

      ADAPTER_NAME = "Mysql2"

      include MySQL::DatabaseStatements

      class << self
        def new_client(config)
          Mysql2::Client.new(config)
        rescue Mysql2::Error => error
          if error.error_number == ConnectionAdapters::Mysql2Adapter::ER_BAD_DB_ERROR
            raise ActiveRecord::NoDatabaseError.db_error(config[:database])
          elsif error.error_number == ConnectionAdapters::Mysql2Adapter::ER_ACCESS_DENIED_ERROR
            raise ActiveRecord::DatabaseConnectionError.username_error(config[:username])
          elsif [ConnectionAdapters::Mysql2Adapter::ER_CONN_HOST_ERROR, ConnectionAdapters::Mysql2Adapter::ER_UNKNOWN_HOST_ERROR].include?(error.error_number)
            raise ActiveRecord::DatabaseConnectionError.hostname_error(config[:host])
          else
            raise ActiveRecord::ConnectionNotEstablished, error.message
          end
        end
      end

      def initialize(connection, logger, connection_options, config)
        check_prepared_statements_deprecation(config)
        superclass_config = config.reverse_merge(prepared_statements: false)
        super(connection, logger, connection_options, superclass_config)
      end

      def self.database_exists?(config)
        !!ActiveRecord::Base.mysql2_connection(config)
      rescue ActiveRecord::NoDatabaseError
        false
      end

      def supports_json?
        !mariadb? && database_version >= "5.7.8"
      end

      def supports_comments?
        true
      end

      def supports_comments_in_create?
        true
      end

      def supports_savepoints?
        true
      end

      def savepoint_errors_invalidate_transactions?
        true
      end

      def supports_lazy_transactions?
        true
      end

      # HELPER METHODS ===========================================

      def each_hash(result, &block) # :nodoc:
        if block_given?
          result.each(as: :hash, symbolize_keys: true, &block)
        else
          to_enum(:each_hash, result)
        end
      end

      def error_number(exception)
        exception.error_number if exception.respond_to?(:error_number)
      end

      #--
      # QUOTING ==================================================
      #++

      def quote_string(string)
        @raw_connection.escape(string)
      rescue Mysql2::Error => error
        raise translate_exception(error, message: error.message, sql: "<escape>", binds: [])
      end

      #--
      # CONNECTION MANAGEMENT ====================================
      #++

      def active?
        @raw_connection.ping
      end

      def reconnect!(restore_transactions: false)
        @lock.synchronize do
          @raw_connection.close
          connect
          super
        end
      end
      alias :reset! :reconnect!

      # Disconnects from the database if already connected.
      # Otherwise, this method does nothing.
      def disconnect!
        super
        @raw_connection.close
      end

      def discard! # :nodoc:
        super
        @raw_connection.automatic_close = false
        @raw_connection = nil
      end

      private
        def check_prepared_statements_deprecation(config)
          if !config.key?(:prepared_statements)
            ActiveSupport::Deprecation.warn(<<-MSG.squish)
              The default value of `prepared_statements` for the mysql2 adapter will be changed from +false+ to +true+ in Rails 7.2.
            MSG
          end
        end

        def connect
          @raw_connection = self.class.new_client(@config)
        end

        def configure_connection
          @raw_connection.query_options[:as] = :array
          super
        end

        def full_version
          schema_cache.database_version.full_version_string
        end

        def get_full_version
          @raw_connection.server_info[:version]
        end

        def translate_exception(exception, message:, sql:, binds:)
          if exception.is_a?(Mysql2::Error::TimeoutError) && !exception.error_number
            ActiveRecord::AdapterTimeout.new(message, sql: sql, binds: binds)
          else
            super
          end
        end
    end
  end
end

mysql_database_tasks.rb

# frozen_string_literal: true

module ActiveRecord
  module Tasks # :nodoc:
    class MySQLDatabaseTasks # :nodoc:
      ER_DB_CREATE_EXISTS = 1007

      delegate :connection, :establish_connection, to: ActiveRecord::Base

      def self.using_database_configurations?
        true
      end

      def initialize(db_config)
        @db_config = db_config
        @configuration_hash = db_config.configuration_hash
      end

      def create
        establish_connection(configuration_hash_without_database)
        connection.create_database(db_config.database, creation_options)
        establish_connection(db_config)
      end

      def drop
        establish_connection(db_config)
        connection.drop_database(db_config.database)
      end

      def purge
        establish_connection(db_config)
        connection.recreate_database(db_config.database, creation_options)
      end

      def charset
        connection.charset
      end

      def collation
        connection.collation
      end

      def structure_dump(filename, extra_flags)
        args = prepare_command_options
        args.concat(["--result-file", "#{filename}"])
        args.concat(["--no-data"])
        args.concat(["--routines"])
        args.concat(["--skip-comments"])

        ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
        if ignore_tables.any?
          args += ignore_tables.map { |table| "--ignore-table=#{db_config.database}.#{table}" }
        end

        args.concat([db_config.database.to_s])
        args.unshift(*extra_flags) if extra_flags

        run_cmd("mysqldump", args, "dumping")
      end

      def structure_load(filename, extra_flags)
        args = prepare_command_options
        args.concat(["--execute", %{SET FOREIGN_KEY_CHECKS = 0; SOURCE #{filename}; SET FOREIGN_KEY_CHECKS = 1}])
        args.concat(["--database", db_config.database.to_s])
        args.unshift(*extra_flags) if extra_flags

        run_cmd("mysql", args, "loading")
      end

      private
        attr_reader :db_config, :configuration_hash

        def configuration_hash_without_database
          configuration_hash.merge(database: nil)
        end

        def creation_options
          Hash.new.tap do |options|
            options[:charset]     = configuration_hash[:encoding]   if configuration_hash.include?(:encoding)
            options[:collation]   = configuration_hash[:collation]  if configuration_hash.include?(:collation)
          end
        end

        def prepare_command_options
          args = {
            host:      "--host",
            port:      "--port",
            socket:    "--socket",
            username:  "--user",
            password:  "--password",
            encoding:  "--default-character-set",
            sslca:     "--ssl-ca",
            sslcert:   "--ssl-cert",
            sslcapath: "--ssl-capath",
            sslcipher: "--ssl-cipher",
            sslkey:    "--ssl-key"
          }.filter_map { |opt, arg| "#{arg}=#{configuration_hash[opt]}" if configuration_hash[opt] }

          args
        end

        def run_cmd(cmd, args, action)
          fail run_cmd_error(cmd, args, action) unless Kernel.system(cmd, *args)
        end

        def run_cmd_error(cmd, args, action)
          msg = +"failed to execute: `#{cmd}`\n"
          msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
          msg
        end
    end
  end
end

named.rb

# frozen_string_literal: true

module ActiveRecord
  # = Active Record \Named \Scopes
  module Scoping
    module Named
      extend ActiveSupport::Concern

      module ClassMethods
        # Returns an ActiveRecord::Relation scope object.
        #
        #   posts = Post.all
        #   posts.size # Fires "select count(*) from  posts" and returns the count
        #   posts.each {|p| puts p.name } # Fires "select * from posts" and loads post objects
        #
        #   fruits = Fruit.all
        #   fruits = fruits.where(color: 'red') if options[:red_only]
        #   fruits = fruits.limit(10) if limited?
        #
        # You can define a scope that applies to all finders using
        # {default_scope}[rdoc-ref:Scoping::Default::ClassMethods#default_scope].
        def all
          scope = current_scope

          if scope
            if self == scope.klass
              scope.clone
            else
              relation.merge!(scope)
            end
          else
            default_scoped
          end
        end

        def scope_for_association(scope = relation) # :nodoc:
          if current_scope&.empty_scope?
            scope
          else
            default_scoped(scope)
          end
        end

        # Returns a scope for the model with default scopes.
        def default_scoped(scope = relation, all_queries: nil)
          build_default_scope(scope, all_queries: all_queries) || scope
        end

        def default_extensions # :nodoc:
          if scope = scope_for_association || build_default_scope
            scope.extensions
          else
            []
          end
        end

        # Adds a class method for retrieving and querying objects.
        # The method is intended to return an ActiveRecord::Relation
        # object, which is composable with other scopes.
        # If it returns +nil+ or +false+, an
        # {all}[rdoc-ref:Scoping::Named::ClassMethods#all] scope is returned instead.
        #
        # A \scope represents a narrowing of a database query, such as
        # <tt>where(color: :red).select('shirts.*').includes(:washing_instructions)</tt>.
        #
        #   class Shirt < ActiveRecord::Base
        #     scope :red, -> { where(color: 'red') }
        #     scope :dry_clean_only, -> { joins(:washing_instructions).where('washing_instructions.dry_clean_only = ?', true) }
        #   end
        #
        # The above calls to #scope define class methods <tt>Shirt.red</tt> and
        # <tt>Shirt.dry_clean_only</tt>. <tt>Shirt.red</tt>, in effect,
        # represents the query <tt>Shirt.where(color: 'red')</tt>.
        #
        # Note that this is simply 'syntactic sugar' for defining an actual
        # class method:
        #
        #   class Shirt < ActiveRecord::Base
        #     def self.red
        #       where(color: 'red')
        #     end
        #   end
        #
        # Unlike <tt>Shirt.find(...)</tt>, however, the object returned by
        # <tt>Shirt.red</tt> is not an Array but an ActiveRecord::Relation,
        # which is composable with other scopes; it resembles the association object
        # constructed by a {has_many}[rdoc-ref:Associations::ClassMethods#has_many]
        # declaration. For instance, you can invoke <tt>Shirt.red.first</tt>, <tt>Shirt.red.count</tt>,
        # <tt>Shirt.red.where(size: 'small')</tt>. Also, just as with the
        # association objects, named \scopes act like an Array, implementing
        # Enumerable; <tt>Shirt.red.each(&block)</tt>, <tt>Shirt.red.first</tt>,
        # and <tt>Shirt.red.inject(memo, &block)</tt> all behave as if
        # <tt>Shirt.red</tt> really was an array.
        #
        # These named \scopes are composable. For instance,
        # <tt>Shirt.red.dry_clean_only</tt> will produce all shirts that are
        # both red and dry clean only. Nested finds and calculations also work
        # with these compositions: <tt>Shirt.red.dry_clean_only.count</tt>
        # returns the number of garments for which these criteria obtain.
        # Similarly with <tt>Shirt.red.dry_clean_only.average(:thread_count)</tt>.
        #
        # All scopes are available as class methods on the ActiveRecord::Base
        # descendant upon which the \scopes were defined. But they are also
        # available to {has_many}[rdoc-ref:Associations::ClassMethods#has_many]
        # associations. If,
        #
        #   class Person < ActiveRecord::Base
        #     has_many :shirts
        #   end
        #
        # then <tt>elton.shirts.red.dry_clean_only</tt> will return all of
        # Elton's red, dry clean only shirts.
        #
        # \Named scopes can also have extensions, just as with
        # {has_many}[rdoc-ref:Associations::ClassMethods#has_many] declarations:
        #
        #   class Shirt < ActiveRecord::Base
        #     scope :red, -> { where(color: 'red') } do
        #       def dom_id
        #         'red_shirts'
        #       end
        #     end
        #   end
        #
        # Scopes can also be used while creating/building a record.
        #
        #   class Article < ActiveRecord::Base
        #     scope :published, -> { where(published: true) }
        #   end
        #
        #   Article.published.new.published    # => true
        #   Article.published.create.published # => true
        #
        # \Class methods on your model are automatically available
        # on scopes. Assuming the following setup:
        #
        #   class Article < ActiveRecord::Base
        #     scope :published, -> { where(published: true) }
        #     scope :featured, -> { where(featured: true) }
        #
        #     def self.latest_article
        #       order('published_at desc').first
        #     end
        #
        #     def self.titles
        #       pluck(:title)
        #     end
        #   end
        #
        # We are able to call the methods like this:
        #
        #   Article.published.featured.latest_article
        #   Article.featured.titles
        def scope(name, body, &block)
          unless body.respond_to?(:call)
            raise ArgumentError, "The scope body needs to be callable."
          end

          if dangerous_class_method?(name)
            raise ArgumentError, "You tried to define a scope named \"#{name}\" " \
              "on the model \"#{self.name}\", but Active Record already defined " \
              "a class method with the same name."
          end

          if method_defined_within?(name, Relation)
            raise ArgumentError, "You tried to define a scope named \"#{name}\" " \
              "on the model \"#{self.name}\", but ActiveRecord::Relation already defined " \
              "an instance method with the same name."
          end

          extension = Module.new(&block) if block

          if body.respond_to?(:to_proc)
            singleton_class.define_method(name) do |*args|
              scope = all._exec_scope(*args, &body)
              scope = scope.extending(extension) if extension
              scope
            end
          else
            singleton_class.define_method(name) do |*args|
              scope = body.call(*args) || all
              scope = scope.extending(extension) if extension
              scope
            end
          end
          singleton_class.send(:ruby2_keywords, name)

          generate_relation_method(name)
        end

        private
          def singleton_method_added(name)
            generate_relation_method(name) if Kernel.respond_to?(name) && !ActiveRecord::Relation.method_defined?(name)
          end
      end
    end
  end
end

named_function.rb

# frozen_string_literal: true

module Arel # :nodoc: all
  module Nodes
    class NamedFunction < Arel::Nodes::Function
      attr_accessor :name

      def initialize(name, expr, aliaz = nil)
        super(expr, aliaz)
        @name = name
      end

      def hash
        super ^ @name.hash
      end

      def eql?(other)
        super && self.name == other.name
      end
      alias :== :eql?
    end
  end
end

nested_attributes.rb

# frozen_string_literal: true

require "active_support/core_ext/hash/except"
require "active_support/core_ext/module/redefine_method"
require "active_support/core_ext/hash/indifferent_access"

module ActiveRecord
  module NestedAttributes # :nodoc:
    class TooManyRecords < ActiveRecordError
    end

    extend ActiveSupport::Concern

    included do
      class_attribute :nested_attributes_options, instance_writer: false, default: {}
    end

    # = Active Record Nested Attributes
    #
    # Nested attributes allow you to save attributes on associated records
    # through the parent. By default nested attribute updating is turned off
    # and you can enable it using the accepts_nested_attributes_for class
    # method. When you enable nested attributes an attribute writer is
    # defined on the model.
    #
    # The attribute writer is named after the association, which means that
    # in the following example, two new methods are added to your model:
    #
    # <tt>author_attributes=(attributes)</tt> and
    # <tt>pages_attributes=(attributes)</tt>.
    #
    #   class Book < ActiveRecord::Base
    #     has_one :author
    #     has_many :pages
    #
    #     accepts_nested_attributes_for :author, :pages
    #   end
    #
    # Note that the <tt>:autosave</tt> option is automatically enabled on every
    # association that accepts_nested_a

no_touching.rb

node.rb

node_expression.rb

nodes.rb

null_encryptor.rb

null_relation.rb

numericality.rb

oid.rb

optimistic.rb

order_predications.rb

ordering.rb

outer_join.rb

over.rb

persistence.rb

pessimistic.rb

plain_string.rb

point.rb

polymorphic_array_value.rb

pool_config.rb

pool_manager.rb

postgresql.rb

postgresql_adapter.rb

postgresql_database_tasks.rb

predicate_builder.rb

predications.rb

preloader.rb

presence.rb

primary_key.rb

properties.rb

query.rb

query_attribute.rb

query_cache.rb

query_logs.rb

query_methods.rb

querying.rb

queue.rb

quoting.rb

railtie.rb

range.rb

range_handler.rb

read.rb

read_only_null_encryptor.rb

readonly_attributes.rb

reaper.rb

record_fetch_warning.rb

referential_integrity.rb

reflection.rb

regexp.rb

relation.rb

relation_handler.rb

render_context.rb

resolver.rb

result.rb

right_outer_join.rb

runtime_registry.rb

sanitization.rb

savepoints.rb

schema.rb

schema_cache.rb

schema_creation.rb

schema_definitions.rb

schema_dumper.rb

schema_migration.rb

schema_statements.rb

scheme.rb

scoping.rb

secure_password.rb

secure_token.rb

select_core.rb

select_manager.rb

select_statement.rb

serialization.rb

serialized.rb

session.rb

shard_selector.rb

signed_id.rb

singular_association.rb

spawn_methods.rb

specialized_string.rb

sql_literal.rb

sql_string.rb

sql_type_metadata.rb

sqlite.rb

sqlite3_adapter.rb

sqlite_database_tasks.rb

statement_cache.rb

statement_pool.rb

store.rb

string_join.rb

substitute_binds.rb

suppressor.rb

table.rb

table_alias.rb

table_metadata.rb

table_row.rb

table_rows.rb

terminal.rb

test_databases.rb

test_fixtures.rb

text.rb

through_association.rb

time.rb

time_zone_conversion.rb

timestamp.rb

timestamp_with_time_zone.rb

timezone.rb

to_sql.rb

touch_later.rb

transaction.rb

transactions.rb

translation.rb

tree_manager.rb

true.rb