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stubtest: __all__ check seems to ignore *.allowlist files #17277
Description
Bug Report
mypy stubtest started failing on contextlib2 a while back, and I'm finally getting around to trying to fix it. Most of the issues have been resolved just by updating the stub to the latest version from typeshed (with the appropriate edits for contextlib2), but I had trouble getting this error to go away:
error: contextlib2.__all__ names exported from the stub do not correspond to the names exported at runtime. This is probably due to things being missing from the stub or an inaccurate `__all__` in the stub
Stub: in file /home/ncoghlan/devel/contextlib2/contextlib2/__init__.pyi
Names exported in the stub but not at runtime: []
Runtime:
Names exported at runtime but not in the stub: ['ContextStack']
For the specific case of contextlib2, I was able to resolve it by just dropping ContextStack from the runtime __all__ (it's a long-deprecated API that nobody should be using at all, let alone via import *), but it seems wrong that the warning was emitted at all given that contextlib2.ContextStack is listed in https://github.com/jazzband/contextlib2/blob/master/dev/mypy.allowlist (at least, it was when I was getting this error. I commented it out later after mypy complained that the entry wasn't needed anymore - it may be that mypy's type inferencing has improved to the point where it can now derive the ContextStack method signatures from the ExitStack ones)
Adding ContextStack just to __all__ in the stub without adding an actual spec for it didn't make the error go away.
Expected Behavior
Listing contextlib2.ContextStack in the mypy.allowlist file would make mypy never care about that name, including in the __all__ check.
Actual Behavior
__all__ error as shown above
Your Environment
- Mypy version used:
mypy 1.8.0 (compiled: no) - Mypy command-line:
python -m mypy.stubtest --allowlist dev/mypy.allowlist contextlib2 - Mypy configuration options from
mypy.ini(and other config files): defaults (no config files) - Python version used: mostly Python 3.12, but reproduced on 3.8 -> 3.11 with tox
Activity
hauntsaninja commentedon May 22, 2024
Thanks for the issue. As of mypy 1.9, if there's an error with
contextlib2.__all__, the entry in the allowlist should becontextlib2.__all__(before that, it was justcontextlib2, see #14217).I'm inclined to keep it this way, since
__all__is the actual symbol that has the discrepancy. E.g. if there's something aboutContextStackthat stubtest can't understand, that feels different enough from whether or not__all__is correct that you wouldn't want to silence everythingncoghlan commentedon May 23, 2024
Given that the resolution in my case was "If it isn't important enough to include in the stub file, it doesn't make sense to leave it in
__all__either", I'm finding it hard to think of a case where it actually would be critical that a name that didn't typecheck absolutely had to be included in__all_.On that basis, I agree the current behaviour is fine (either names that don't typecheck have to be left out of the runtime
__all__as well as the typechecked one, or else the__all__check has to be turned off entirely for that module)