Make Packwerk work in in-repo gems and other dependencies

[lastgabs]

Description
Currently Packwerk can only check constant references that are being autoloaded. This excludes any dependencies and in-repo gems that could exist in a codebase. Especially for in-repo gems we have a strong need for boundary checking.

To Reproduce
Add a package.yml with enforced privacy or dependency violations and run packwerk update or packwerk check, neither of these will work for non-autoloaded packages.

Expected Behaviour
Dependencies and other packages that are not autoloaded should still have boundaries enforced.

Version Information

• Packwerk: v1.0.0
• Ruby: 2.7.1p83

[tomstuart]

@lastgabs and I discussed this on the pod hangout and I suggested she try adding the in-repo gems to the load_paths in packwerk.yml and see what happens. She’s going to do that shortly and report back.

[tomstuart]

(Maybe I should’ve suggested package_paths instead. The distinction is not very clear to me.)

[exterm]

I investigated how to decouple from zeitwerk and documented the findings in Shopify/constant_resolver#26.

Seems actually like using Sorbet is the best bet, but that would be a major rewrite of packwerk. Might still make sense at some point.

[alexevanczuk]

This is an older issue but also wanted to link #218 which provides an implementation for and interesting discussion around allowing packwerk to work in any gems that use zeitwerk for autoloading!

[Mifrill]

Hey, I just wanna ask for any updates on this.
I face it during the research for trying to enforce boundaries of external gem with package.yml config.
I.e. Gemfile includes any external gem and this gem has package.yml file with a public interface, and I want to enforce privacy violations for that external gem. I thought it possible via extension config, but it's not, and packwerk validate getting failed due to relative paths checks, even if I put explicitly absolute path to main package.yml file:

dependencies:
  - ../my_external_gems/my_gem

and packwerk update-todo also cannot catch violations from external gem as well, even with Zeitwerk::Loader.eager_load_all setup. So I think this issue is exactly about it (in terms of other dependencies). Is it in the plans?