Ensure json is loaded before using responders.

actionpack/lib/abstract_controller/rendering.rb

 require "abstract_controller/base"
-require "action_view/base"
 
 module AbstractController
   class DoubleRenderError < Error

actionpack/lib/action_controller/metal/responder.rb

+require 'active_support/json'
+
 module ActionController #:nodoc:
   # Responder is responsible for exposing a resource to different mime requests,
   # usually depending on the HTTP verb. The responder is triggered when