无法访问嵌套的Ruby模块中的类

Question

I'm fighting with nested modules and access to classes in these modules in ruby.

I created a simple example to show my problem. app.rb and test.rb are placed in the same folder while sub_test.rb is placed in a sub-folder called test .

app.rb

# /app.rb
require_relative 'test.rb'

Test::NotWorkingClass.work

test.rb

# /test.rb
module Test
  require_relative 'test/sub_test'

  class NotWorkingClass
    def self.work
      puts 'Test::NotWorkingClass.work'
    end
  end
end

test/sub_test.rb

# /test/sub_test.rb
module Test
  module SubTest
    Test::NotWorkingClass.work
  end
end

When executing the app I'm getting this error:

/test/sub_test.rb:3:in `<module:SubTest>': uninitialized constant Test::NotWorkingClass (NameError)

When I commented out the execution of Test::NotWorkingClass in sub_test.rb everything works fine.

And now the strange thing I didn't understand. I modified my example by creating a file called not_working_class.rb in test folder and include it in the test.rb file:

test.rb

# /test.rb
module Test
    require_relative 'test/not_working_class'
    require_relative 'test/sub_test'
end

test/not_working_class.rb

# /test/not_working_class.rb
module Test
  class NotWorkingClass
    def self.work
      puts 'Test::NotWorkingClass.work'
    end
  end
end

And now, the example works.

So why can't I access Classes defined in the test.rb file but can access them when defined in separate file?

Answer 1

As the error message suggests, test/sub_test.rb can not find Test::NotWorkingClass .

You should add require_relative "../test" in test/sub_test.rb , and remove the require_relative 'test/sub_test' in test.rb

Answer 2

So the problem is where the require statement is at.

If you put require_relative "../test" inside test/sub_test.rb it creates circular require because test.rb requires test/sub_test.rb

If you put require_relative "../test" inside test/sub_test.rb and then add require_relative "test/sub_test.rb" inside app.rb then it'll work