Closed
Description
As a follow up to #27393 I think I made a mistake in just typing some of the return values to be Callable. The following script highlights that issue:
from pandas.util._decorators import Appender
def func1(num: int) -> int:
return num
@Appender("")
def func2(num: int) -> int:
return num
reveal_type(func1)
reveal_type(func2)If you run that from the project root you'll get something like the following:
$ mypy foo.py
foo.py:10: note: Revealed type is 'def (num: builtins.int) -> builtins.int'
foo.py:11: note: Revealed type is 'def (*Any, **Any) -> Any'We probably want to maintain the types of the signature for func2 so I think need to use TypeVar for generic support.
More info on the mypy side in:
python/mypy#3113
python/mypy#1551
So I think need something like:
T = TypeVar('T', bound=Callable[..., Any])
# then decorators can return
-> Callable[[T], T]