I have a class that stores user configuration in my Rails app.
While porting to Rails 3, I got a strange error. I was able to
isolate the problem. Steps to reproduce:
class Configuration
end
- Add a controller settings_controller.rb:
class SettingsController < ApplicationController
def index
@config = Configuration.new
end
end
resources :settings
require 'test_helper'
class SettingsControllerTest < ActionController::TestCase
test "boom" do
get :index
end
end
When run, the test outputs the following error (see below for
the full backtrace):
1) Error:
test_boom(SettingsControllerTest):
NoMethodError: undefined method `protected_instance_variables' for #<Configuration:0x2878258>
method test_boom in settings_controller_test.rb at line 6
When I change the name of the instance variable, everything
works fine. From a developer's perspective, if @config is not
allowed as an instance variable name in controllers, there should
be at least a warning. On the other hand, reserving very common
instance variable names such as @config seems a bit too restrictive
and should at least be well documented.
I also noticed that the constant name ::Config seems to be
reserved by Rails 3.0.0rc; I think the same applies here.
If desired, I can push my test application to github, just let
me know.
Here's the full backtrace:
1) Error:
test_boom(SettingsControllerTest):
NoMethodError: undefined method `protected_instance_variables' for #<Configuration:0x2870ecc>
method protected_instance_variables in activesupport (3.0.0.rc) lib/active_support/configurable.rb at line 22
method view_assigns in actionpack (3.0.0.rc) lib/abstract_controller/rendering.rb at line 130
method view_context in actionpack (3.0.0.rc) lib/abstract_controller/rendering.rb at line 86
method _render_template in actionpack (3.0.0.rc) lib/abstract_controller/rendering.rb at line 114
method render_to_body in actionpack (3.0.0.rc) lib/abstract_controller/rendering.rb at line 108
method render_to_body in actionpack (3.0.0.rc) lib/action_controller/metal/renderers.rb at line 47
method render_to_body in actionpack (3.0.0.rc) lib/action_controller/metal/compatibility.rb at line 55
method render_to_string in actionpack (3.0.0.rc) lib/abstract_controller/rendering.rb at line 101
method render in actionpack (3.0.0.rc) lib/abstract_controller/rendering.rb at line 92
method render in actionpack (3.0.0.rc) lib/action_controller/metal/rendering.rb at line 17
method render in actionpack (3.0.0.rc) lib/action_controller/metal/instrumentation.rb at line 40
method ms in activesupport (3.0.0.rc) lib/active_support/core_ext/benchmark.rb at line 5
method realtime in benchmark.rb at line 308
method ms in activesupport (3.0.0.rc) lib/active_support/core_ext/benchmark.rb at line 5
method render in actionpack (3.0.0.rc) lib/action_controller/metal/instrumentation.rb at line 40
method cleanup_view_runtime in actionpack (3.0.0.rc) lib/action_controller/metal/instrumentation.rb at line 78
method cleanup_view_runtime in activerecord (3.0.0.rc) lib/active_record/railties/controller_runtime.rb at line 15
method render in actionpack (3.0.0.rc) lib/action_controller/metal/instrumentation.rb at line 39
method default_render in actionpack (3.0.0.rc) lib/action_controller/metal/implicit_render.rb at line 10
method send_action in actionpack (3.0.0.rc) lib/action_controller/metal/implicit_render.rb at line 5
method process_action in actionpack (3.0.0.rc) lib/abstract_controller/base.rb at line 136
method process_action in actionpack (3.0.0.rc) lib/action_controller/metal/rendering.rb at line 11
method process_action in actionpack (3.0.0.rc) lib/abstract_controller/callbacks.rb at line 18
method _run__987036831__process_action__199225275__callbacks in activesupport (3.0.0.rc) lib/active_support/callbacks.rb at line 429
method send in activesupport (3.0.0.rc) lib/active_support/callbacks.rb at line 404
method _run_process_action_callbacks in activesupport (3.0.0.rc) lib/active_support/callbacks.rb at line 404
method send in activesupport (3.0.0.rc) lib/active_support/callbacks.rb at line 93
method run_callbacks in activesupport (3.0.0.rc) lib/active_support/callbacks.rb at line 93
method process_action in actionpack (3.0.0.rc) lib/abstract_controller/callbacks.rb at line 17
method process_action in actionpack (3.0.0.rc) lib/action_controller/metal/instrumentation.rb at line 30
method instrument in activesupport (3.0.0.rc) lib/active_support/notifications.rb at line 52
method instrument in activesupport (3.0.0.rc) lib/active_support/notifications/instrumenter.rb at line 21
method instrument in activesupport (3.0.0.rc) lib/active_support/notifications.rb at line 52
method process_action in actionpack (3.0.0.rc) lib/action_controller/metal/instrumentation.rb at line 29
method process_action in actionpack (3.0.0.rc) lib/action_controller/metal/rescue.rb at line 17
method process in actionpack (3.0.0.rc) lib/abstract_controller/base.rb at line 105
method process in actionpack (3.0.0.rc) lib/abstract_controller/rendering.rb at line 40
method process_with_new_base_test in actionpack (3.0.0.rc) lib/action_controller/metal/testing.rb at line 12
method process in actionpack (3.0.0.rc) lib/action_controller/test_case.rb at line 404
method get in actionpack (3.0.0.rc) lib/action_controller/test_case.rb at line 342
method test_boom in settings_controller_test.rb at line 6
method __send__ in activesupport (3.0.0.rc) lib/active_support/testing/setup_and_teardown.rb at line 67
method run in activesupport (3.0.0.rc) lib/active_support/testing/setup_and_teardown.rb at line 67
method _run_setup_callbacks in activesupport (3.0.0.rc) lib/active_support/callbacks.rb at line 428
method run in activesupport (3.0.0.rc) lib/active_support/testing/setup_and_teardown.rb at line 65
Samuel Kadolph