Rails 6：未初始化的常量 ActionText::Engine::ApplicationController (NameError)答案

【问题标题】：Rails 6: uninitialized constant ActionText::Engine::ApplicationController (NameError)Rails 6：未初始化的常量 ActionText::Engine::ApplicationController (NameError)
【发布时间】：2019-11-23 19:25:54
【问题描述】：

Puma caught this error: uninitialized constant ActionText::Engine::ApplicationController (NameError)
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/actiontext-6.0.1/lib/action_text/engine.rb:43:in `block (2 levels) in <class:Engine>'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:429:in `instance_exec'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:429:in `block in make_lambda'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:201:in `block (2 levels) in halting'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:607:in `block (2 levels) in default_terminator'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:606:in `catch'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:606:in `block in default_terminator'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:202:in `block in halting'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:514:in `block in invoke_before'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:514:in `each'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:514:in `invoke_before'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:134:in `run_callbacks'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/execution_wrapper.rb:119:in `complete!'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/execution_wrapper.rb:76:in `ensure in block in run!'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/execution_wrapper.rb:76:in `block in run!'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/execution_wrapper.rb:70:in `tap'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-6.0.1/lib/active_support/execution_wrapper.rb:70:in `run!'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/executor.rb:12:in `call'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/static.rb:126:in `call'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/sendfile.rb:111:in `call'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/host_authorization.rb:83:in `call'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/webpacker-4.2.0/lib/webpacker/dev_server_proxy.rb:23:in `perform_request'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rack-proxy-0.6.5/lib/rack/proxy.rb:57:in `call'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/railties-6.0.1/lib/rails/engine.rb:526:in `call'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/puma-4.3.0/lib/puma/configuration.rb:228:in `call'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/puma-4.3.0/lib/puma/server.rb:667:in `handle_request'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/puma-4.3.0/lib/puma/server.rb:470:in `process_client'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/puma-4.3.0/lib/puma/server.rb:328:in `block in run'
C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/puma-4.3.0/lib/puma/thread_pool.rb:134:in `block in spawn_thread'

【问题讨论】：

欢迎来到stackoverflow。请注意，这篇文章不构成本网站的适当问题。您应该花点时间阅读How do I ask a good question?，然后回到这里并根据那里的所有指南更新您的帖子。具体来说，您需要在帖子中包含一个实际问题、您为解决问题所采取的步骤、您如何到达那里的说明，最好是minimal reproducible example。
你能在 new Rails 项目中重现这个吗？

标签： ruby-on-rails ruby ruby-on-rails-6

【解决方案1】：

您的应用很可能缺少ApplicationController 类。如果它在app/controllers/application_controller.rb 下，你能仔细检查一下吗？

如果您没有立即找到该文件，请不要担心！您的应用程序的结构可能不依赖于定义ApplicationController。 ActionText 有一个长期存在的问题，因此您可能难以使用它。

您可以跟踪这个讨论在项目中使用ActionText 的未决问题，这些项目不依赖于默认ApplicationController 类：https://github.com/rails/rails/issues/37183

如果不是你的情况，那么你可以通过在上述目录中创建类来解决这个问题。

享受吧！

【讨论】：

我遇到了这个问题，但 application_controller 仍然出现在正确的位置。
@courtsimas 您能借此机会创建一个新帖子，其中包含回溯以及应用程序控制器和 config/application.rb 文件。如果你喜欢我看看，你可以在这里分享帖子链接:)
如果你有 ApplicationController，检查那里的语法错误