render_exception

# File actionpack/lib/action_dispatch/middleware/debug_exceptions.rb, line 64
    def render_exception(request, exception)
      backtrace_cleaner = request.get_header('action_dispatch.backtrace_cleaner')
      wrapper = ExceptionWrapper.new(backtrace_cleaner, exception)
      log_error(request, wrapper)

      if request.get_header('action_dispatch.show_detailed_exceptions')
        case @response_format
        when :api
          render_for_api_application(request, wrapper)
        when :default
          render_for_default_application(request, wrapper)
        end
      else
        raise exception
      end
    end