Packwerk doesn't support custom root namespaces for root directories in the load path about packwerk

[exterm]

is there any reason we don't just ask zeitwerk itself for where a constant lives?

We investigated that in the beginning, but for zeitwerk determining the location of a constant involves loading constants. IIRC, to resolve Sales::Order, zeitwerk would first load Sales, then register an autoload on it for Order on it, then execute that.

My memory is a little fuzzy but the takeaway is that for zeitwerk, resolving constants involves loading constants, and we deemed that to be too slow, especially seeing as loading one constant can create a whole cascade of other constants to load.

[mclark]

Just to be clear, if there is no opposition to this change (which shouldn't affect anyone except those using the esoteric Zeitwerk::Loader#push_dir method), then I'm happy to start work on a branch to add this support.

[exterm]

I think this generally makes sense. I'm curious to see what the implementation would look like, but I don't expect any blockers there.

It looks like the bulk of the implementation for this would live in constant_resolver, so as a next step I'd be interested in seeing a test case that shows the new behavior on that level.

I'd also be curious to hear what @rafaelfranca and @alexevanczuk think about this change, in case I'm missing something. My impression is that this adds a small amount of complexity, in a pretty contained fashion--I don't expect many additions to packwerk itself--for the benefit of being more compatible with Rails.

[rafaelfranca]

I'm ok with this change, we already require Zeitwerk to be used in the application in order to Packwerk to check.

[alexevanczuk]

Agreed – my understanding is this is all about making sure that we can properly identify the file path where a constant is defined, and part of doing so is making sure that constant_resolver understands all of zeitwerks features.

Quick question... is there any reason we don't just ask zeitwerk itself for where a constant lives? Now that rails is loaded in the environment while parsing files, I wonder if we can just ask zeitwerk directly. I'm not sure that makes sense, but it might allow us to resolve all issues where constant_resolver doesn't implement a zeitwerk feature in one fell swoop. I'm not sure this API is even available in zeitwerk, or if it is, if it's reliable without eager loading the application. Just a thought!