ActiveRecord assign_nested_attributes_for_collection_association bug

association-extension-failing.rb

# frozen_string_literal: true

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  gem "activerecord", "5.2.0"
  gem "sqlite3"
end

require "active_record"
require "minitest/autorun"
require "logger"

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
    t.string :a
    t.string :b
  end
end

module PostCommentsExtension
  def build(attributes = {})
    super({ b: 'from extension'}.merge(attributes))
  end
end

class Post < ActiveRecord::Base
  has_many :comments, extend: PostCommentsExtension
  accepts_nested_attributes_for :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_association_stuff
    post = Post.create!
    comment = post.comments.build
    assert_equal 'from extension', comment.b

    post = Post.create!
    post.comments_attributes = [{ a: 'comment 1'}]
    assert_equal 'from extension', post.comments[0].b
  end
end

association-extension-fixed.rb

# frozen_string_literal: true

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  gem "activerecord", "5.2.0"
  gem "sqlite3"
end

require "active_record"
require "minitest/autorun"
require "logger"

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
    t.string :a
    t.string :b
  end
end

module PostCommentsExtension
  def build(attributes = {})
    super({ b: 'from extension'}.merge(attributes))
  end
end

class Post < ActiveRecord::Base
  has_many :comments, extend: PostCommentsExtension
  accepts_nested_attributes_for :comments

  # override for method defined in: activerecord/lib/active_record/nested_attributes.rb
  # the only change is on lines 92/93
  def assign_nested_attributes_for_collection_association(association_name, attributes_collection)
    options = nested_attributes_options[association_name]
    if attributes_collection.respond_to?(:permitted?)
      attributes_collection = attributes_collection.to_h
    end

    unless attributes_collection.is_a?(Hash) || attributes_collection.is_a?(Array)
      raise ArgumentError, "Hash or Array expected for attribute `#{association_name}`, got #{attributes_collection.class.name} (#{attributes_collection.inspect})"
    end

    check_record_limit!(options[:limit], attributes_collection)

    if attributes_collection.is_a? Hash
      keys = attributes_collection.keys
      attributes_collection = if keys.include?("id") || keys.include?(:id)
        [attributes_collection]
      else
        attributes_collection.values
      end
    end

    association = association(association_name)

    existing_records = if association.loaded?
      association.target
    else
      attribute_ids = attributes_collection.map { |a| a["id"] || a[:id] }.compact
      attribute_ids.empty? ? [] : association.scope.where(association.klass.primary_key => attribute_ids)
    end

    attributes_collection.each do |attributes|
      if attributes.respond_to?(:permitted?)
        attributes = attributes.to_h
      end
      attributes = attributes.with_indifferent_access

      if attributes["id"].blank?
        unless reject_new_record?(association_name, attributes)
          # association.build(attributes.except(*UNASSIGNABLE_KEYS))
          association.reader.build(attributes.except(*UNASSIGNABLE_KEYS))
        end
      elsif existing_record = existing_records.detect { |record| record.id.to_s == attributes["id"].to_s }
        unless call_reject_if(association_name, attributes)
          # Make sure we are operating on the actual object which is in the association's
          # proxy_target array (either by finding it, or adding it if not found)
          # Take into account that the proxy_target may have changed due to callbacks
          target_record = association.target.detect { |record| record.id.to_s == attributes["id"].to_s }
          if target_record
            existing_record = target_record
          else
            association.add_to_target(existing_record, :skip_callbacks)
          end

          assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy])
        end
      else
        raise_nested_attributes_record_not_found!(association_name, attributes["id"])
      end
    end
  end
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_association_stuff
    post = Post.create!
    comment = post.comments.build
    assert_equal 'from extension', comment.b

    post = Post.create!
    post.comments_attributes = [{ a: 'comment 1'}]
    assert_equal 'from extension', post.comments[0].b
  end
end