F821 false positive for .pyi

[JonathanPlasse]

class Distribution(IMetadataProvider): ...
class IMetadataProvider: ...

ruff detects the F821 while flake8 with flake8-pyi does not (flake8-pyi must be installed otherwise it will also detect an error).

Link to the playground

[ngnpope]

Surely this is correct though? At the time of declaration of Distribution it is necessary for IMetadataProvider to have been already declared.

[JonathanPlasse]

No, it is allowed in stub files, this is taken from typeshed. Stub files are only read by linters never executed.

[ngnpope]

Ok. Fair enough, I know declarations in stub files can be out of order. I guess I'm wondering why the declarations cannot just be reordered?

[JonathanPlasse]

You are right even if it is allowed does not mean it should be done.
Should it be fixed?

[JonathanPlasse]

I vote fixing it.

[charliermarsh]

Can you look into how flake8-pyi suppresses these? What mechanism is it using? I'm surprised.

[JonathanPlasse]

This is done here.
When you run flake8 with flake8-pyi installed with --verbose you can see this

❯ flake8 stubs/setuptools/pkg_resources/__init__.pyi --verbose
flake8.checker            MainProcess     91 INFO     Making checkers
flake8.bugbear            MainProcess    107 INFO     Optional warning B950 not present in selected warnings: None. Not firing it at all.
flake8.pyi                MainProcess    119 INFO     Replacing FlakesChecker with PyiAwareFlakesChecker while checking 'stubs/setuptools/pkg_resources/__init__.pyi'
flake8.main.application   MainProcess    194 INFO     Finished running
flake8.main.application   MainProcess    194 INFO     Reporting errors
flake8.main.application   MainProcess    195 INFO     Found a total of 209 violations and reported 0

[charliermarsh]

Woah that's wild!

[charliermarsh]

Yeah, we should probably just change the behavior of ast.rs on pyi files to match whatever they do there then.