Should TCH run on pyi files?

[MarcoGorelli]

Hi,

See here: pandas-dev/pandas#51794

The TCH code is reporting lots of errors in typing stub files (.pyi) - is this right? They're only used by the type checker anyway, perhaps TCH shouldn't run for this file type?

[charliermarsh]

My initial reaction is that you’re right. Let me see what the originating plug-in does (though we may want to change it anyway even if they run on pyi files).

[MarcoGorelli]

I didn't think flake8 ran on cython files to begin with (or at least, wasn't meant to)

[charliermarsh]

Sorry, I might be misunderstanding - we’re talking about pyi stub files here, not Cython files, right?

[MarcoGorelli]

sorry I'm mixing up things (in pandas I think .pyi files are only used to provide annotations for cython files), but the link makes it look like flake8 is only supposed to run on Python files

running it on a directory doesn't pick up the stub files, but indeed, passing them explicitly, the original plugin would flag them

(.311venv) marcogorelli@DESKTOP-U8OKFP3:~/pandas-dev$ flake8 pandas/_libs --select=TC001
(.311venv) marcogorelli@DESKTOP-U8OKFP3:~/pandas-dev$ flake8 pandas/_libs/lib.pyi --select=TC001
pandas/_libs/lib.pyi:16:1: TC001 Move application import 'pandas._typing.DtypeObj' into a type-checking block
pandas/_libs/lib.pyi:16:1: TC001 Move application import 'pandas._typing.npt' into a type-checking block
pandas/_libs/lib.pyi:16:1: TC001 Move application import 'pandas._typing.ArrayLike' into a type-checking block

[charliermarsh]

Ahh ok, got it. Well, I think it makes sense to exclude these rules from the TCH checks, I don't see a benefit in enforcing those rules on stub files.

[charliermarsh]

I can fix this today.

[twoertwein]

using if TYPE_CHECKING in pyi files probably also violates flake8-pyi's Y002

[charliermarsh]

Oh lol yeah, that sounds bad then!