[FR] Warn about top-level "tests" package in find_packages() by default

[mgorny]

What's the problem this feature will solve?

I often end up reporting bugs about packages using find_packages() without appropriate exclusion lists, that end up installing top-level test or tests directories. These directories are especially problematic since they're bound to cause file collisions between packages, and given their special use I don't think any specific package should be allowed to "own" them.

Describe the solution you'd like

I think it would be best if setuptools could at least warn if find_packages() ends up including test or tests directories, and suggest the package maintainers to exclude them. Perhaps they could also be skipped by default in some future version.

Alternative Solutions

It could be possible to implicitly skip them immediately. While I honestly don't think it would realistically break anything, I'm not sure if someone isn't actually having some workflow relying on this.

Additional context

No response

Code of Conduct

• I agree to follow the PSF Code of Conduct

[drewcassidy]

The docs imply that test folders should be excluded by default, to make things more confusing

[abravalheri]

That is a reasonable feature to implement. Would any of you guys would like to give it a go and provide a PR?

@drewcassidy please notice that the docs you pointed out are for automatic discovery, but the procedure you are using is custom discovery. If you would like to submit a PR to make the docs less confusing that would be very appreciated!

[mgorny]

I'll give it a try today. I guess I'll try to make it warn about all directories that would've been excluded by autodiscovery.