Changed piece of railties-3.0.7.rc1/lib/rails/application/bootstrap.rb Clear dependencies before request only when some changes were made to any file observed by watchr.

bootstrap.rb

      initializer :set_clear_dependencies_hook do
        unless config.cache_classes
          changed_at = Proc.new{ File.new(File.join(Rails.root, '.watchr')).mtime }
          last_change = changed_at.call

          ActionDispatch::Callbacks.before do
            change = changed_at.call                        
            if change > last_change
              Rails.logger.info("DETECTED CHANGES")
              last_change = change
              ActiveSupport::DescendantsTracker.clear
              ActiveSupport::Dependencies.clear
            end
          end
        end
      end