Use autoloading instead of requiring all files up front

[mcmire]

We have a lot of files which are like active_record.rb where there are a bunch of requires at the top of the file. I've never liked this because there are different files at different levels being required. This is not as organized as it could be, and if you add a new file, it's confusing where to add the require. I've started using autoload in other projects and I find it easier to manage. We should do the same thing here.

For instance, for active_record.rb, we might change this to something like:

module Shoulda
  module Matchers
    module ActiveRecord
      autoload :AssociationMatcher, "shoulda/matchers/active_record/association_matcher"
      autoload :AssociationMatchers, "shoulda/matchers/active_record/association_matchers"
      autoload :HaveDbColumnMatcher, "shoulda/matchers/active_record/have_db_column_matcher"
      # ...
    end
  end
end

[vsppedro]

Hi, @mcmire, I would love to work on this!

[mcmire]

@vsppedro Okay, that would be awesome! I will assign this to you :)

[vsppedro]

Thanks!

[n-rodriguez]

@mcmire why not using Zeitwerk?

[mcmire]

@n-rodriguez I'm not sure that Zeitwerk would be a good choice here. It seems like it's really well suited for applications, but it seems overkill for gems IMO. It would have to be added as a runtime dependency and I don't feel like people should have to bring in Zeitwerk to use shoulda-matchers.

[n-rodriguez]

but it seems overkill for gems IMO.

IMO this PR is the perfect use case for Zeitwerk since you do exactly what it does.

[vsppedro]

@mcmire First, sorry for the problems with the PR and thank you for releasing the fix so fast.

For now, I will focus on adding the tests first, as described by you here: #1333 (comment). After adding these tests I will continue with this PR - if that's okay with you.

[mcmire]

@vsppedro Yeah, that's fine with me!

[mcmire]

I'm going to close this issue. It seems like this is a relatively minor pain point and is actually more complicated than I thought it would be.