ArgumentError：ApplicationController 的副本已從模塊樹中刪除但仍處於活動狀態

Question

我在 Rails 4.0.0.rc2 中使用 ActiveAdmin（帶有為 Rails 4 定制的 gemset）。 應用程序還具有基於 railscasts #385和#386 的定制授權代碼。

當我更改 ActiveAdmin 資源文件中的某些內容並嘗試刷新瀏覽器頁面時，我在current_permission方法中收到此錯誤：

/admin/courses 中的 ArgumentError

ApplicationController 的副本已從模塊樹中刪除，但仍處於活動狀態！

如果我再次嘗試刷新，我會得到：

自動加載常量權限時檢測到循環依賴

我認為這個問題與在更改源文件后在開發模式下自動加載類有關。 我看過類似的問題帖子，但它們是針對 rails 2.3.x 的。 此外，該解決方案似乎在unloadable此錯誤的控制器中指定unloadable ，但我不確定在 ActiveAdmin 中將此代碼段放在何處。

這也可能與 ActiveAdmin 無關。 它可能與權限類的構建方式及其在應用程序控制器中的使用有關。 如果我在 ActiveAdmin 資源類中添加一個skip_before_filter :authorize ，這個錯誤就會消失。

應用控制器：

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception

  before_filter :authenticate_user!
  before_filter :authorize

  delegate :allow_action?, to: :current_permission
  helper_method :allow_action?

  delegate :allow_param?, to: :current_permission
  helper_method :allow_param?

  private
    def current_permission
      @current_permission ||= Permissions.permission_for(current_user)
    end

    def current_resource
      nil
    end

    def authorize
      if current_permission.allow_action?(params[:controller], params[:action], current_resource)
        current_permission.permit_params! params
      else
        redirect_to root_url, alert: "Not authorized."
      end
    end
end

權限.rb：

module Permissions
  def self.permission_for(user)
    if user.nil?
      GuestPermission.new
    elsif user.admin?
      AdminPermission.new(user)
    else
      UserPermission.new(user)
    end
  end
end

管理員/courses.rb：

ActiveAdmin.register Course do
  index do
    column :name
    column :description
    column :duration
    column :status
    column :price
    default_actions
  end

  filter :discipline
  filter :level
  filter :lessons
  filter :name
  filter :status
end

Gemfile（相關行）：

gem 'rails', '4.0.0.rc2'

# Use puma as the app server
gem 'puma'

# Administration - Temporary github refs until rails 4 compatible releases
gem 'responders',          github: 'plataformatec/responders'
gem 'inherited_resources', github: 'josevalim/inherited_resources'
gem 'ransack',             github: 'ernie/ransack',            branch: 'rails-4'
gem 'activeadmin',         github: 'gregbell/active_admin', branch: 'rails4'
gem 'formtastic',          github: 'justinfrench/formtastic'

參數錯誤：

ArgumentError - A copy of ApplicationController has been removed from the module tree but is still active!:
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:445:in `load_missing_constant'
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:183:in `const_missing'
  rspec-core (2.13.1) lib/rspec/core/backward_compatibility.rb:24:in `const_missing'
  app/controllers/application_controller.rb:17:in `current_permission'
  app/controllers/application_controller.rb:25:in `authorize'
  activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:417:in `_run__1040990970961152968__process_action__callbacks'
  activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:80:in `run_callbacks'
  actionpack (4.0.0.rc2) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (4.0.0.rc2) lib/action_controller/metal/rescue.rb:29:in `process_action'
  actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
  activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `block in instrument'
  activesupport (4.0.0.rc2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
  activesupport (4.0.0.rc2) lib/active_support/notifications.rb:159:in `instrument'
  actionpack (4.0.0.rc2) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
  actionpack (4.0.0.rc2) lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
  activerecord (4.0.0.rc2) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  actionpack (4.0.0.rc2) lib/abstract_controller/base.rb:136:in `process'
  actionpack (4.0.0.rc2) lib/abstract_controller/rendering.rb:44:in `process'
  actionpack (4.0.0.rc2) lib/action_controller/metal.rb:195:in `dispatch'
  actionpack (4.0.0.rc2) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
  actionpack (4.0.0.rc2) lib/action_controller/metal.rb:231:in `block in action'
  actionpack (4.0.0.rc2) lib/action_dispatch/routing/route_set.rb:80:in `dispatch'
  actionpack (4.0.0.rc2) lib/action_dispatch/routing/route_set.rb:48:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/journey/router.rb:71:in `block in call'
  actionpack (4.0.0.rc2) lib/action_dispatch/journey/router.rb:59:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/routing/route_set.rb:655:in `call'
  omniauth (1.1.4) lib/omniauth/strategy.rb:184:in `call!'
  omniauth (1.1.4) lib/omniauth/strategy.rb:164:in `call'
  omniauth (1.1.4) lib/omniauth/strategy.rb:184:in `call!'
  omniauth (1.1.4) lib/omniauth/strategy.rb:164:in `call'
  omniauth (1.1.4) lib/omniauth/strategy.rb:184:in `call!'
  omniauth (1.1.4) lib/omniauth/strategy.rb:164:in `call'
  newrelic_rpm (3.6.4.122) lib/new_relic/rack/error_collector.rb:12:in `call'
  newrelic_rpm (3.6.4.122) lib/new_relic/rack/agent_hooks.rb:22:in `call'
  newrelic_rpm (3.6.4.122) lib/new_relic/rack/browser_monitoring.rb:16:in `call'
  newrelic_rpm (3.6.4.122) lib/new_relic/rack/developer_mode.rb:28:in `call'
  meta_request (0.2.7) lib/meta_request/middlewares/app_request_handler.rb:13:in `call'
  rack-contrib (1.1.0) lib/rack/contrib/response_headers.rb:17:in `call'
  meta_request (0.2.7) lib/meta_request/middlewares/headers.rb:16:in `call'
  meta_request (0.2.7) lib/meta_request/middlewares/meta_request_handler.rb:13:in `call'
  warden (1.2.1) lib/warden/manager.rb:35:in `block in call'
  warden (1.2.1) lib/warden/manager.rb:34:in `call'
  rack (1.5.2) lib/rack/etag.rb:23:in `call'
  rack (1.5.2) lib/rack/conditionalget.rb:25:in `call'
  rack (1.5.2) lib/rack/head.rb:11:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/flash.rb:241:in `call'
  rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context'
  rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/cookies.rb:486:in `call'
  activerecord (4.0.0.rc2) lib/active_record/query_cache.rb:36:in `call'
  activerecord (4.0.0.rc2) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
  activerecord (4.0.0.rc2) lib/active_record/migration.rb:369:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
  activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:373:in `_run__2183739952227501342__call__callbacks'
  activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:80:in `run_callbacks'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/reloader.rb:64:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
  better_errors (0.9.0) lib/better_errors/middleware.rb:84:in `protected_app_call'
  better_errors (0.9.0) lib/better_errors/middleware.rb:79:in `better_errors_call'
  better_errors (0.9.0) lib/better_errors/middleware.rb:56:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
  railties (4.0.0.rc2) lib/rails/rack/logger.rb:38:in `call_app'
  railties (4.0.0.rc2) lib/rails/rack/logger.rb:21:in `block in call'
  activesupport (4.0.0.rc2) lib/active_support/tagged_logging.rb:67:in `block in tagged'
  activesupport (4.0.0.rc2) lib/active_support/tagged_logging.rb:25:in `tagged'
  activesupport (4.0.0.rc2) lib/active_support/tagged_logging.rb:67:in `tagged'
  railties (4.0.0.rc2) lib/rails/rack/logger.rb:21:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/request_id.rb:21:in `call'
  rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
  rack (1.5.2) lib/rack/runtime.rb:17:in `call'
  activesupport (4.0.0.rc2) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
  rack (1.5.2) lib/rack/lock.rb:17:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/static.rb:64:in `call'
  railties (4.0.0.rc2) lib/rails/engine.rb:511:in `call'
  railties (4.0.0.rc2) lib/rails/application.rb:97:in `call'
  rack (1.5.2) lib/rack/content_length.rb:14:in `call'
  puma (2.1.1) lib/puma/server.rb:369:in `handle_request'
  puma (2.1.1) lib/puma/server.rb:246:in `process_client'
  puma (2.1.1) lib/puma/server.rb:145:in `block in run'
  puma (2.1.1) lib/puma/thread_pool.rb:92:in `block in spawn_thread'

運行時錯誤：循環依賴：

RuntimeError - Circular dependency detected while autoloading constant Permissions:
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:460:in `load_missing_constant'
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:183:in `const_missing'
  rspec-core (2.13.1) lib/rspec/core/backward_compatibility.rb:24:in `const_missing'
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:686:in `remove_constant'
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:516:in `block in remove_unloadable_constants!'
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:516:in `remove_unloadable_constants!'
  activesupport (4.0.0.rc2) lib/active_support/dependencies.rb:300:in `clear'
  railties (4.0.0.rc2) lib/rails/application/finisher.rb:90:in `block (2 levels) in <module:Finisher>'
  activesupport (4.0.0.rc2) lib/active_support/file_update_checker.rb:75:in `execute'
  railties (4.0.0.rc2) lib/rails/application/finisher.rb:105:in `block (2 levels) in <module:Finisher>'
  activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:377:in `_run__2753119820186226816__prepare__callbacks'
  activesupport (4.0.0.rc2) lib/active_support/callbacks.rb:80:in `run_callbacks'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/reloader.rb:74:in `prepare!'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/reloader.rb:62:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
  better_errors (0.9.0) lib/better_errors/middleware.rb:84:in `protected_app_call'
  better_errors (0.9.0) lib/better_errors/middleware.rb:79:in `better_errors_call'
  better_errors (0.9.0) lib/better_errors/middleware.rb:56:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
  railties (4.0.0.rc2) lib/rails/rack/logger.rb:38:in `call_app'
  railties (4.0.0.rc2) lib/rails/rack/logger.rb:21:in `block in call'
  activesupport (4.0.0.rc2) lib/active_support/tagged_logging.rb:67:in `block in tagged'
  activesupport (4.0.0.rc2) lib/active_support/tagged_logging.rb:25:in `tagged'
  activesupport (4.0.0.rc2) lib/active_support/tagged_logging.rb:67:in `tagged'
  railties (4.0.0.rc2) lib/rails/rack/logger.rb:21:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/request_id.rb:21:in `call'
  rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
  rack (1.5.2) lib/rack/runtime.rb:17:in `call'
  activesupport (4.0.0.rc2) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
  rack (1.5.2) lib/rack/lock.rb:17:in `call'
  actionpack (4.0.0.rc2) lib/action_dispatch/middleware/static.rb:64:in `call'
  railties (4.0.0.rc2) lib/rails/engine.rb:511:in `call'
  railties (4.0.0.rc2) lib/rails/application.rb:97:in `call'
  rack (1.5.2) lib/rack/content_length.rb:14:in `call'
  puma (2.1.1) lib/puma/server.rb:369:in `handle_request'
  puma (2.1.1) lib/puma/server.rb:246:in `process_client'
  puma (2.1.1) lib/puma/server.rb:145:in `block in run'
  puma (2.1.1) lib/puma/thread_pool.rb:92:in `block in spawn_thread'

任何線索都會有所幫助。 如果您需要查看應用程序中的其他代碼片段，請告訴我。

Answer 1

對於未來的訪問者，我想我會對原始問題提供一些說明，即使這個問題已經很老了並且已經有一個公認的答案。

ArgumentError: A copy of X has been removed from the module tree but is still active當您嘗試從未自動重新加載的類（在 lib 目錄中）訪問自動重新加載的類（在 app 目錄中）時，會引發該錯誤。

Answer 2

我不確定為什么會發生這種情況，但我找到了一個解決方法。 改變這個：

def current_permission
  @current_permission ||= Permissions.permission_for(current_user)
end

對此：

def current_permission
  @current_permission ||= ::Permissions.permission_for(current_user)
end

此時在 ActiveSupport 中引發錯誤：

# Load the constant named +const_name+ which is missing from +from_mod+. If
# it is not possible to load the constant into from_mod, try its parent
# module using +const_missing+.
def load_missing_constant(from_mod, const_name)
  log_call from_mod, const_name

  unless qualified_const_defined?(from_mod.name) && Inflector.constantize(from_mod.name).equal?(from_mod)
    raise ArgumentError, "A copy of #{from_mod} has been removed from the module tree but is still active!"
  end
  # ...
end

只有當您沒有完全限定常量名稱時才會出現問題，因此 Rails 嘗試在ApplicationController命名空間中查找它。

Answer 3

在你 development.rb 暫時試試放

config.cache_classes = true

它對我有用。

Answer 4

我沒有使用 ActiveAdmin，但我剛剛經歷了對 ApplicationController 的循環依賴。

問題是輔助模塊聲明不正確：

app/helpers/home_helper.rb

聲明為：

module StaticHelper

解決這個問題后，一切都很美好。 我沒有研究為什么會發生這種情況，Rails 也沒有返回更智能的錯誤消息。

Answer 5

您可以嘗試將此行放在config/initializers/active_admin.rb ：

在 Rails <= 4 中：

 config.skip_before_filter :load_footer_variables

在 Rails 中 >= 5

config.skip_before_action :load_footer_variables

就像這里建議的那樣。

Answer 6

ArgumentError at /admin/dashboard

A copy of ApplicationController has been removed from the module tree but is still active!

今天在更改 ActiveAdmin 視圖時發生在我身上 - rails 服務器重啟解決了這個問題。