copy

# File activerecord/lib/active_record/migration.rb, line 1052
    def copy(destination, sources, options = {})
      copied = []

      FileUtils.mkdir_p(destination) unless File.exist?(destination)
      schema_migration = SchemaMigration::NullSchemaMigration.new
      internal_metadata = InternalMetadata::NullInternalMetadata.new

      destination_migrations = ActiveRecord::MigrationContext.new(destination, schema_migration, internal_metadata).migrations
      last = destination_migrations.last
      sources.each do |scope, path|
        source_migrations = ActiveRecord::MigrationContext.new(path, schema_migration, internal_metadata).migrations

        source_migrations.each do |migration|
          source = File.binread(migration.filename)
          inserted_comment = "# This migration comes from #{scope} (originally #{migration.version})\n"
          magic_comments = +""
          loop do
            # If we have a magic comment in the original migration,
            # insert our comment after the first newline(end of the magic comment line)
            # so the magic keep working.
            # Note that magic comments must be at the first line(except sh-bang).
            source.sub!(/\A(?:#.*\b(?:en)?coding:\s*\S+|#\s*frozen_string_literal:\s*(?:true|false)).*\n/) do |magic_comment|
              magic_comments << magic_comment; ""
            end || break
          end

          if !magic_comments.empty? && source.start_with?("\n")
            magic_comments << "\n"
            source = source[1..-1]
          end

          source = "#{magic_comments}#{inserted_comment}#{source}"

          if duplicate = destination_migrations.detect { |m| m.name == migration.name }
            if options[:on_skip] && duplicate.scope != scope.to_s
              options[:on_skip].call(scope, migration)
            end
            next
          end

          migration.version = next_migration_number(last ? last.version + 1 : 0).to_i
          new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.#{scope}.rb")
          old_path, migration.filename = migration.filename, new_path
          last = migration

          File.binwrite(migration.filename, source)
          copied << migration
          options[:on_copy].call(scope, migration, old_path) if options[:on_copy]
          destination_migrations << migration
        end
      end

      copied
    end