Move respond_with definition to own module and avoid monkey-patching

app/controllers/application_controller.rb

@@ -12,6 +12,7 @@ class ApplicationController < ActionController::Base
   include CablecarResponses
   include Pagy::Backend
   include RequestTimeouts
+  include RespondWith
 
   self.responder = ApplicationResponder
   respond_to :html

app/controllers/concerns/respond_with.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module RespondWith
+  extend ActiveSupport::Concern
+
+  def respond_with(*resources, &)
+    if self.class.mimes_for_respond_to.empty?
+      raise "In order to use respond_with, first you need to declare the formats your " \
+            "controller responds to in the class level"
+    end
+
+    return unless (collector = retrieve_collector_from_mimes(&))
+
+    options = resources.size == 1 ? {} : resources.extract_options!
+
+    # Fix spree issues #3531 and #2210 (patch provided by leiyangyou)
+    if (defined_response = collector.response) &&
+       !ApplicationController.spree_responders[self.class.to_s.to_sym]
+           .try(:[], action_name.to_sym)
+
+      if action = options.delete(:action)
+        render(action:)
+      else
+        defined_response.call
+      end
+    else
+      # The action name is needed for processing
+      options[:action_name] = action_name.to_sym
+      # If responder is not specified then pass in Spree::Responder
+      (options.delete(:responder) || Spree::Responder).call(self, resources, options)
+    end
+  end
+
+  private
+
+  def retrieve_collector_from_mimes(mimes = nil, &block)
+    mimes ||= collect_mimes_from_class_level
+    collector = Collector.new(mimes, request.variant)
+    block.call(collector) if block_given?
+    format = collector.negotiate_format(request)
+
+    raise ActionController::UnknownFormat unless format
+
+    _process_format(format)
+    collector
+  end
+end

lib/spree/core/controller_helpers/respond_with.rb

@@ -1,52 +1,5 @@
 # frozen_string_literal: true
 
-require 'spree/responder'
-
-module ActionController
-  class Base
-    def respond_with(*resources, &)
-      if self.class.mimes_for_respond_to.empty?
-        raise "In order to use respond_with, first you need to declare the formats your " \
-              "controller responds to in the class level"
-      end
-
-      return unless (collector = retrieve_collector_from_mimes(&))
-
-      options = resources.size == 1 ? {} : resources.extract_options!
-
-      # Fix spree issues #3531 and #2210 (patch provided by leiyangyou)
-      if (defined_response = collector.response) &&
-         !ApplicationController.spree_responders[self.class.to_s.to_sym].try(:[],
-                                                                             action_name.to_sym)
-        if action = options.delete(:action)
-          render(action:)
-        else
-          defined_response.call
-        end
-      else
-        # The action name is needed for processing
-        options[:action_name] = action_name.to_sym
-        # If responder is not specified then pass in Spree::Responder
-        (options.delete(:responder) || Spree::Responder).call(self, resources, options)
-      end
-    end
-
-    private
-
-    def retrieve_collector_from_mimes(mimes = nil, &block)
-      mimes ||= collect_mimes_from_class_level
-      collector = Collector.new(mimes, request.variant)
-      block.call(collector) if block_given?
-      format = collector.negotiate_format(request)
-
-      raise ActionController::UnknownFormat unless format
-
-      _process_format(format)
-      collector
-    end
-  end
-end
-
 module Spree
   module Core
     module ControllerHelpers