Regenerate AV::Base subclass when DetailsKey gets cleared

actionview/lib/action_view/base.rb

@@ -185,9 +185,14 @@ def with_empty_template_cache # :nodoc:
         template_container = Module.new
         Class.new(self) {
           include template_container
-          define_method(:compiled_method_container) { template_container }
+          define_method(:compiled_method_container)           { template_container }
+          define_singleton_method(:compiled_method_container) { template_container }
         }
       end
+
+      def changed?(other) # :nodoc:
+        compiled_method_container != other.compiled_method_container
+      end
     end
 
     attr_reader :view_renderer

actionview/lib/action_view/rendering.rb

@@ -35,14 +35,35 @@ def process(*) #:nodoc:
     end
 
     module ClassMethods
+      def _routes
+      end
+
+      def _helpers
+      end
+
+      def build_av_class(klass, supports_path, routes, helpers)
+        Class.new(klass) do
+          if routes
+            include routes.url_helpers(supports_path)
+            include routes.mounted_helpers
+          end
+
+          if helpers
+            include helpers
+          end
+        end
+      end
+
       def view_context_class
         klass = ActionView::LookupContext::DetailsKey.view_context_class(ActionView::Base)
 
-        @view_context_class ||= build_view_context_class(klass, supports_path?, _routes, _helpers)
+        @view_context_class ||= build_av_class(klass, supports_path?, _routes, _helpers)
 
         if klass.changed?(@view_context_class)
-          @view_context_class = build_view_context_class(klass, supports_path?, _routes, _helpers)
+          @view_context_class = build_av_class(klass, supports_path?, _routes, _helpers)
         end
+
+        @view_context_class
       end
     end