failsafe_rescue

# File actionpack/lib/action_controller/dispatcher.rb, line 185
      def failsafe_rescue(exception)
        self.class.failsafe_response(@output, '500 Internal Server Error', exception) do
          if @controller ||= defined?(::ApplicationController) ? ::ApplicationController : Base
            @controller.process_with_exception(@request, @response, exception).out(@output)
          else
            raise exception
          end
        end
      end