Make action_method? public and change implicit rendering to override it instead.

actionpack/lib/abstract_controller/base.rb

@@ -128,20 +128,23 @@ module AbstractController
       self.class.action_methods
     end
 
-    private
+    # Returns true if the name can be considered an action. This can
+    # be overridden in subclasses to modify the semantics of what
+    # can be considered an action.
+    #
+    # For instance, this is overriden by ActionController to add
+    # the implicit rendering feature.
+    #
+    # ==== Parameters
+    # * <tt>name</tt> - The name of an action to be tested
+    #
+    # ==== Returns
+    # * <tt>TrueClass</tt>, <tt>FalseClass</tt>
+    def action_method?(name)
+      self.class.action_methods.include?(name)
+    end
 
-      # Returns true if the name can be considered an action. This can
-      # be overridden in subclasses to modify the semantics of what
-      # can be considered an action.
-      #
-      # ==== Parameters
-      # * <tt>name</tt> - The name of an action to be tested
-      #
-      # ==== Returns
-      # * <tt>TrueClass</tt>, <tt>FalseClass</tt>
-      def action_method?(name)
-        self.class.action_methods.include?(name)
-      end
+    private
 
       # Call the action. Override this in a subclass to modify the
       # behavior around processing an action. This, and not #process,
@@ -160,8 +163,8 @@ module AbstractController
       # If the action name was not found, but a method called "action_missing"
       # was found, #method_for_action will return "_handle_action_missing".
       # This method calls #action_missing with the current action name.
-      def _handle_action_missing
-        action_missing(@_action_name)
+      def _handle_action_missing(*args)
+        action_missing(@_action_name, *args)
       end
 
       # Takes an action name and returns the name of the method that will

actionpack/lib/action_controller/metal/implicit_render.rb

@@ -14,10 +14,8 @@ module ActionController
       render
     end
 
-    def method_for_action(action_name)
-      super || if template_exists?(action_name.to_s, _prefixes)
-        action_name.to_s
-      end
+    def action_method?(action_name)
+      super || template_exists?(action_name.to_s, _prefixes)
     end
   end
 end

actionpack/test/controller/new_base/render_implicit_action_test.rb

@@ -24,5 +24,10 @@ module RenderImplicitAction
       assert_body   "Hello hyphen-ated!"
       assert_status 200
     end
+
+    test "action_method? returns true for implicit actions" do
+      assert SimpleController.new.action_method?(:hello_world)
+      assert SimpleController.new.action_method?(:"hyphen-ated")
+    end
   end
 end