rails--rails/railties/lib/rails/commands/rake/rake_command.rb

module Rails
  module Command
    class RakeCommand < Base
      namespace "rake"

      class << self
        def printing_commands
          formatted_rake_tasks.map(&:first)
        end

        def perform(task, *)
          require_rake

          ARGV.unshift(task) # Prepend the task, so Rake knows how to run it.

          Rake.application.standard_exception_handling do
            Rake.application.init("rails")
            Rake.application.load_rakefile
            Rake.application.top_level
          end
        end

        private
          def rake_tasks
            require_rake

            return @rake_tasks if defined?(@rake_tasks)

            ActiveSupport::Deprecation.silence do
              Rails::Command.require_application_and_environment!
            end

            Rake::TaskManager.record_task_metadata = true
            Rake.application.instance_variable_set(:@name, "rails")
            Rails.application.load_tasks
            @rake_tasks = Rake.application.tasks.select(&:comment)
          end

          def formatted_rake_tasks
            rake_tasks.map { |t| [ t.name_with_args, t.comment ] }
          end

          def require_rake
            require "rake" # Defer booting Rake until we know it's needed.
          end
      end
    end
  end
end