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inspect.isfunction and inspect.ismethod #10117
Description
Bug Report
I use an union between a callable and a class:
# example.py
import inspect
from typing import Union, Callable, Type
def some_func(
error: Union[Callable[..., BaseException], Type[BaseException]]
)->None:
if (inspect.isfunction(error) or inspect.ismethod(error)):
reveal_type(error)
else:
reveal_type(error)Mypy does not infer that the type is Callable based on inspect.isfunction and inspect.ismethod, but still assumes the union:
example.py:9: note: Revealed type is 'Union[def (*Any, **Any) -> builtins.BaseException, Type[builtins.BaseException]]'
example.py:11: note: Revealed type is 'Union[def (*Any, **Any) -> builtins.BaseException, Type[builtins.BaseException]]'
To Reproduce
Execute the following command:
mypy example.py
Your Environment
- Mypy version used: 0.812
Activity
mristin commentedon Feb 19, 2021
(I am not sure if this is a bug or a feature request, please change as you see fit.)
JelleZijlstra commentedon Feb 19, 2021
This should be fixable in typeshed once we have support for PEP 647 (https://www.python.org/dev/peps/pep-0647/). Mypy could also special-case these functions directly but that might be overkill.
mristin commentedon Feb 20, 2021
@JelleZijlstra thanks for considering the issue. In fact, I think that mypy should handle
inspect.is*methods directly as this seems a canonical way to check whether an object is a callable, a coroutine etc. at runtime.Otherwise, it would be great if mypy documentation explicitly stated how the user is expected to check for "is a callable" property. (There is no
isinstance(obj, Callable)as far as I am aware.)Edit: typo
JelleZijlstra commentedon Feb 20, 2021
We support using
callable()(as of #2627).AlexWaygood commentedon Apr 1, 2022
Hmm, well,
TypeGuardis now supported and the relevant changes to typeshed have been made, but there still seem to be some problems on mypy's end:erictraut commentedon Aug 17, 2023
It looks like this is working as expected with the latest version of mypy.
The first revealed type is now: