Rails 项目中同名的模块和类 [英] module and class with the same name in Rails project

问题描述

今天早些时候我在跑步时遇到了这个问题

sidekiq

我收到以下错误:

<块引用>

I, [2015-09-04T12:43:33.723243 #15197] INFO -- : Celluloid 0.17.1.2 在 BACKPORTED 模式下运行.[ http://git.io/vJf3J ]报告不是类/home/andreydeineko/employees/app/models/report.rb:1:in `'

但是 Report 是 AR 类/模型，没有任何拼写错误.

发生错误的原因是，项目中存在先前定义的名为Report的模块.

为什么会出现这个类和模块名相同的问题?

是否有任何 Ruby/Rails 约定不将类和模块命名为同名?

解决方案

您不能对 Class 和 Module 重复使用相同的名称.在内部，在 Ruby 中模块被表示为类结构，因此它们共享相同的对象空间.

此外，当您定义模块/类时，您可以将名称作为常量访问.

班级报告定义 foop报告"结尾结尾报告=>报告定义?报告=>不变"

其实你也可以写

Report = Class.new 做定义 foop报告"结尾结尾报告 = Report.new报告.foo

长话短说，如果将Report定义为Class，则不能创建同名的Module.

Earlier today I had this problem, when I was running

sidekiq

I was getting the following error:

I, [2015-09-04T12:43:33.723243 #15197]  INFO -- : Celluloid 0.17.1.2 is running in BACKPORTED mode. [ http://git.io/vJf3J ]
Report is not a class
/home/andreydeineko/employees/app/models/report.rb:1:in `<top (required)>'

but Report was AR class/model without any typos.

It occurred the error was due to the fact, that in the project there was previously defined module called Report.

Why is this problem with same class and module name occurred?

Is there any Ruby/Rails convention to not name the class and module with same name?

解决方案

You cannot reuse the same name for a Class and a Module. Internally, in Ruby modules are represented as class structures therefore they share the same object space.

Moreover, when you define a Module/Class, you can access the name as a constant.

class Report
  def foo
    p "report"
  end
end

Report
=> Report

defined? Report
 => "constant"

in fact, you can also write

Report = Class.new do
  def foo
    p "report"
  end
end

report = Report.new
report.foo

Long story short, if you define Report as Class, you cannot create a Module with the same name.

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