checking for nested attributes when attribute names specified to wrap them as well

actionpack/lib/action_controller/metal/params_wrapper.rb

@@ -112,14 +112,15 @@ module ActionController
               else
                 self.include = m.attribute_names
               end
-            end
-            if m.respond_to?(:nested_attributes_options) && m.nested_attributes_options.any?
-              nested_attributes_names = self.nested_attributes_options.keys.map do |key| 
-                key.to_s.concat('_attributes').to_sym
-              end
-              self.include += nested_attributes_names
-            end
 
+              if m.respond_to?(:nested_attributes_options) && m.nested_attributes_options.keys.any?
+                self.include += m.nested_attributes_options.keys.map do |key|
+                  key.to_s.concat("_attributes")
+                end
+              end
+
+              self.include
+            end
           end
         end
       end

actionpack/test/controller/params_wrapper_test.rb

@@ -255,6 +255,20 @@ class ParamsWrapperTest < ActionController::TestCase
       assert_equal "", @response.body
     end
   end
+
+  def test_derived_wrapped_keys_from_nested_attributes
+    def User.nested_attributes_options
+      { person: {} }
+    end
+
+    assert_called(User, :attribute_names, times: 2, returns: ["username"]) do
+      with_default_wrapper_options do
+        @request.env["CONTENT_TYPE"] = "application/json"
+        post :parse, params: { "username" => "sikachu", "person_attributes" => { "title" => "Developer" } }
+        assert_parameters("username" => "sikachu", "person_attributes" => { "title" => "Developer" }, "user" => { "username" => "sikachu", "person_attributes" => { "title" => "Developer" } })
+      end
+    end
+  end
 end
 
 class NamespacedParamsWrapperTest < ActionController::TestCase