Question on File Structure Best Practices

[dcromer]

Hi, I have question regarding the best practices for file structure (ref)

In my Rails project, I organize lengthy constant declarations into separate files in order to keep classes clean.

For example:

# app/models/foo.rb
class Foo
end

# app/models/foo/constants.rb
class Foo
  MY_CONSTANT = ...
end

# elsewhere in app
Foo::MY_CONSTANT

However, Zeitwerk doesn't like this because it maps from filenames to constants, and requires those constants to be defined (ref). So, if you try to load the code above, you'll get an error message:

Excpeted file app/models/foo/constants.rb to define constant Foo::Constants, but didn't.

The obvious solution here is to define Foo::Constants:

# app/models/foo/constants.rb
class Foo
  module Constants
    MY_CONSTANT = ...
  end
end

# elsewhere in app
Foo::Constants::MY_CONSTANT

But, I have a lot of files like foo/constants.rb, and I am lazy. Are there any other alternatives for getting zeitwerk to autoload files like this?

I appreciate the work the team has done in this gem! It's a big improvement.

[fxn]

One possible solution that would flow well with everything would be to define Foo::Constants:

# app/models/foo/constants.rb
module Foo::Constants
  MY_CONSTANT = ...
end

and then include that one in Foo:

# app/models/foo.rb
module Foo
  include Constants
end

That works because to resolve Foo:: MY_CONSTANT Ruby looks the ancestors of Foo up, follows the conventions, works well with reloading.... Also, anyone opening app/models/foo.rb sees clearly that you're injecting constants into Foo.

[dcromer]

Ok, so it sounds like the module has to be defined if the file exists. Thanks for the quick reply.