Codegen script to extract explicit ActiveModel validators from SchemaValidations::ActiveRecord

schema_validations_extractor.rake

# frozen_string_literal: true

namespace :validations do
  desc 'List all model validations defined by schema_validations'
  task list: :environment do
    LIST_OUTPUT = STDOUT
    VALIDATIONS = Hash.new

    # monkey patch SchemaValidations to extract validation metadata instead of applying them
    # gem source: lib/schema_validations/active_record/validations.rb
    SchemaValidations::ActiveRecord::Base::ClassMethods.module_eval do
      # disables real validation patching
      alias_method :_real_validate_logged, :validate_logged

      def validate_logged(method, arg, opts={})
        opts = opts.dup
        # respect SchemaValidations filtering
        if _filter_validation(method, arg)
          if opts[:if]
            opts[:if] = "#{arg}_changed?".to_sym
          end
          # print out validation type, column and options
          validation = "#{method} #{arg.inspect}"
          validation += ", #{opts.inspect[1...-1]}" if opts.any?
          validation += "\n"
          LIST_OUTPUT.puts(validation)
          VALIDATIONS[self] << validation
        end
      end
    end

    Rails.application.eager_load!
    ActiveRecord::Base.descendants.each_with_index do |cls, idx|
      LIST_OUTPUT.puts "#{idx}: #{cls}"
      VALIDATIONS[cls] = []
      cls.send(:load_schema_validations)
    end
  end

  desc 'Update all models with exported validations'
  task load: :list do
    puts 'Applying listed validators within app/models...'
    dir = Dir.glob('app/models/**/*.rb').reject { |path| path =~ %r{/entities/} }

    VALIDATIONS.each do |cls, validators|
      if validators.empty?
        puts "Skipping #{cls}. No validators"
        next
      end

      model_paths = dir.select { |path| path =~ %r{/#{cls.name.underscore}.rb$} }

      model_path = case cls.name
                   when 'User'
                     'app/models/user.rb'
                   when 'Admin::User'
                     'app/models/admin/user.rb'
                   else
                     raise "Ambiguous path #{cls}: #{model_paths}" if model_paths.size > 1
                     model_paths[0]
                   end

      unless model_path
        puts "Could not find #{cls.name} in app/models/"
        next
      end

      source_lines = File.read(model_path).lines
      if source_lines.find { |ln| ln =~ /# codegen schema validations begin/ }
        puts "Skipping #{cls.name}. Already modified"
        next
      end
      # try first validation line
      start_line_idx = Enumerator.new(source_lines).with_index.find { |ln, _idx| ln =~ /validate/ }&.last
      start_line_idx -= 1 if start_line_idx # prepend validations if any were found
      # try class def line
      unless start_line_idx
        start_line_idx = Enumerator.new(source_lines).with_index.find { |ln, _idx| ln =~ /class[\s:\w]+/ }.last
      end

      validators.unshift("# codegen schema validations begin\n")
      validators.append("# codegen schema validations end\n")

      File.open(model_path, 'w') do |f|
        f.write(source_lines[0..start_line_idx].join)
        f.write(validators.map { |ln| "  #{ln}" }.join)
        f.write(source_lines[start_line_idx+1..-1].join)
      end

      puts "#{cls.name} #{model_path}: applied #{validators.size} validations"
    end
    puts 'Done!'
  end
end