1 files changed, 22 insertions, 7 deletions
diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 67d261db77..a00eafc9ed 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -2,6 +2,21 @@ require "action_controller/log_subscriber"
 require "action_controller/metal/params_wrapper"
 
 module ActionController
+  # The <tt>metal</tt> anonymous class was introduced to solve issue with including modules in <tt>ActionController::Base</tt>.
+  # Modules needes to be included in particluar order. First wee need to have <tt>AbstractController::Rendering</tt> included,
+  # next we should include actuall implementation which would be for example <tt>ActionView::Rendering</tt> and after that
+  # <tt>ActionController::Rendering</tt>. This order must be preserved and as we want to have middle module included dynamicaly
+  # <tt>metal</tt> class was introduced. It has <tt>AbstractController::Rendering</tt> included and is parent class of
+  # <tt>ActionController::Base</tt> which includes <tt>ActionController::Rendering</tt>. If we include <tt>ActionView::Rendering</tt>
+  # beetween them to perserve the required order, we can simply do this by:
+  #
+  #   ActionController::Base.superclass.send(:include, ActionView::Rendering)
+  #
+  metal = Class.new(Metal) do
+    include AbstractController::Rendering
+    include ActionController::BasicRendering
+  end
+
   # Action Controllers are the core of a web request in \Rails. They are made up of one or more actions that are executed
   # on request and then either it renders a template or redirects to another action. An action is defined as a public method
   # on the controller, which will automatically be made accessible to the web-server through \Rails Routes.
@@ -160,7 +175,7 @@ module ActionController
   #     render action: "overthere" # won't be called if monkeys is nil
   #   end
   #
-  class Base < Metal
+  class Base < metal
     abstract!
 
     # We document the request and response methods here because albeit they are
@@ -200,7 +215,6 @@ module ActionController
     end
 
     MODULES = [
-      AbstractController::Layouts,
       AbstractController::Translation,
       AbstractController::AssetPaths,
 
@@ -247,11 +261,12 @@ module ActionController
       include mod
     end
 
-    # Define some internal variables that should not be propagated to the view.
-    self.protected_instance_variables = [
-      :@_status, :@_headers, :@_params, :@_env, :@_response, :@_request,
-      :@_view_runtime, :@_stream, :@_url_options, :@_action_has_layout
-    ]
+    def self.default_protected_instance_vars
+      super.concat [
+        :@_status, :@_headers, :@_params, :@_env, :@_response, :@_request,
+        :@_view_runtime, :@_stream, :@_url_options, :@_action_has_layout
+      ]
+    end
 
     ActiveSupport.run_load_hooks(:action_controller, self)
   end