Type hints for utils.Lock.acquire (and __enter__) incorrect

[clo-vis]

Lock.acquire is defined as:

def acquire(...) -> typing.IO[typing.AnyStr]:

but typing.AnyStr is a TypeVar, and "A function returning TypeVar should receive at least one argument containing the same TypeVar" (this is what mypy should have said).

See python/mypy#16113

As a result, when I write

from portalocker import Lock

def load_binary_file(path: str) -> bytes:
    with Lock(path, mode="rb") as file:
        return file.read()  #  mypy and pyright complain

I get the errors:

mypy: Incompatible return value type (got "str", expected "bytes")
pyright: Return type is unknown

[wolph]

The stalebot 🤦🏻‍♂️

On the bright side, at least it reminds me of this issue. I'm working on getting portalocker pyright strict so this should be fixed soon :)