Rails 6:Zeitwerk::NameError 不从模块加载类 [英] Rails 6: Zeitwerk::NameError doesn't load class from module

问题描述

我有一个看起来像这样的文件

I have a file which looks like this

#app/services/account/authenticate/base.rb
module Account
  module Authenticate
    AuthenticateError = Class.new(StandardError)

    class Base < ::Account::Base
      def self.call(*attrs)
        raise NotImplementedError
      end
    end
  end
end

现在当我从 rails c 运行代码时出现错误

Now when I will run the code from rails c I have an error

> ::Account::Authenticate::AuthenticateError
=> NameError (uninitialized constant Account::Authenticate::AuthenticateError)
> ::Account::Authenticate.constants
=> [:Base, :ViaToken]

所以 rails 没有看到 AuthenticateError 类.但是当我从这个文件夹创建一个嵌套类时，比如

So rails doesn't see AuthenticateError class. But when I will create a nested class from this folder like

=> Account::Authenticate::ViaToken
> ::Account::Authenticate.constants
=> [:Base, :AuthenticateError, :ViaToken]

AuthenticateError 类现在可见

AuthenticateError class is now visible

> ::Account::Authenticate::AuthenticateError
=> Account::Authenticate::AuthenticateError

这个问题的解决方案是创建一个单独的文件authenticate_error.rb，它从一开始就可以工作，但这个解决方案对我来说并不理想.是否有任何解决方案可以预加载所有类或 smth?

The solution for this problem is to create a separate file authenticate_error.rb which will work from the beginning but this solution is not ideal for me. Is there any solution to preload all classes or smth?

(Ruby 2.6 和 Rails 6.0.0.rc2)

(Ruby 2.6 with Rails 6.0.0.rc2)

推荐答案

我在将 Rails 6.0.2 应用程序部署到 Ubuntu 18.04 服务器时遇到了同样的问题.

I experienced this same issue when deploying a Rails 6.0.2 application to an Ubuntu 18.04 server.

无法加载应用程序:Zeitwerk::NameError:预期文件/home/deploy/myapp/app/models/concerns/designation.rb 定义常量 Designation，但没有

Unable to load application: Zeitwerk::NameError: expected file /home/deploy/myapp/app/models/concerns/designation.rb to define constant Designation, but didn't

我发现问题出在 zeitwerk.Zeitwerk 是 Rails 6 中使用的新代码加载器引擎.它旨在成为所有 Rails 6+ 项目的新默认引擎，取代旧的经典引擎.Zeitwerk 提供代码自动加载、预先加载和重新加载的功能.

I found out that the issue was with zeitwerk. Zeitwerk is the new code loader engine used in Rails 6. It’s meant to be the new default for all Rails 6+ projects replacing the old classic engine. Zeitwerk provides the features of code autoloading, eager loading, and reloading.

我是这样解决的:

导航到项目中的 config/application.rb 文件.

Navigate to the config/application.rb file on your project.

在您的应用程序模块中添加此行以切换到 classic 模式以进行自动加载:

Add this line within your application module to switch to classic mode for autoloading:

config.autoloader = :classic

这是一个例子:

module MyApp
  class Application < Rails::Application
    # Initialize configuration defaults for originally generated Rails version.
    config.load_defaults 6.0

    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration can go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded after loading
    # the framework and any gems in your application.

    config.autoloader = :classic
  end
end

您可以在这篇文章中阅读有关 zeitwerk 的更多信息:了解 Rails 6 中的 Zeitwerk

You can read up more on zeitwerk in this article: Understanding Zeitwerk in Rails 6

仅此而已.

我希望这会有所帮助

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