Would it be possible to broaden classmethod to accept ParamSpec when MyPy's support is better? #7689
Description
It could be something like:
P = ParamSpec('P')
class classmethod(Generic[P, _R_co]):
@property
def __func__(self) -> Callable[P, _R_co]: ...
@property
def __isabstractmethod__(self) -> bool: ...
def __init__(self: classmethod[_R_co], __f: Callable[P, _R_co]) -> None: ...
def __get__(self, __obj: _T, __type: type[_T] | None = ...) -> Callable[P, _R_co]: ...
if sys.version_info >= (3, 10):
__name__: str
__qualname__: str
__wrapped__: Callable[P, _R_co]
Activity
AlexWaygood commented on Apr 26, 2022
This is on my to-do list for as soon as mypy 0.950 is released 🙂
JelleZijlstra commented on Apr 26, 2022
Though I'm not sure how much of a difference this will make, considering how thoroughly type checkers special case classmethod (and staticmethod).
AlexWaygood commented on Apr 26, 2022
Also, staticmethod is quite a lot easier than classmethod. staticmethod doesn't change the signature of the function it wraps, but classmethod does -- it requires Concatenate. It would be something like this:
NeilGirdhar commented on Apr 26, 2022
@JelleZijlstra Yup, I just learned about that here. It's not too big a deal since it's very rare that you decorate class methods, but maybe after classmethod is broadened they might consider producing a classmethod[P, R, T] instead of a Callable[Concatenate[type[T], P], R].
AlexWaygood commented on Apr 28, 2022
Mypy 0.950 is now out, but sadly we still cannot use ParamSpec in classmethod or staticmethod due to python/mypy#12011. (abc.abstractclassmethod and abc.abstractstaticmethod inherit from classmethod and staticmethod respectively, so while that mypy issue is outstanding, we cannot make builtins.staticmethod or builtins.classmethod generic over a parameter specification without breaking those two classes.)