Twice-forwarded args and kwargs

[dpmccabe]

I have a function that is designed to retry an arbitrary function call some number of times:

P = ParamSpec("P")
R = TypeVar("R")

def maybe_retry(
    func: Callable[P, R],
    retryable_exceptions: tuple[Type[Exception], ...] = tuple([Exception]),
    max_attempts: int = 0,
    *args: P.args,
    **kwargs: P.kwargs,
) -> R:
    if max_attempts == 0:
        return func(*args, **kwargs) # etc.

I have another function that wraps API requests and handles responses:

def call_api(func: Callable, *args: object, **kwargs: object) -> Any:
    res = maybe_retry(
        func,
        retryable_exceptions=(requests.ConnectionError, requests.ConnectTimeout),
        *args,
        **kwargs,
    ) # etc.

While this code works, Pyright gives me this error:

Argument of type "object" cannot be assigned to parameter "max_attempts" of type "int" in function "maybe_retry"
    "object" is incompatible with "int" (reportArgumentType)

Basically, any maybe_retry keyword argument that I don't specify when I call it results in such an error. Is there any way to resolve this? I'm open to refactoring and dropping the option for positional args if that would make the typing easier.

[erictraut]

Pyright is doing the right thing here. For comparison, mypy emits the same error.

One workaround is to replace the object annotations with Any in the call_api signature.

If you want to retain more type safety, you can do the following:

def call_api(
    func: Callable[P, R], max_attempts: int = 0, *args: P.args, **kwargs: P.kwargs
) -> R:
    return maybe_retry(
        func,
        retryable_exceptions=(requests.ConnectionError, requests.ConnectTimeout),
        max_attempts=max_attempts,
        *args,
        **kwargs,
    )

[dpmccabe]

Any is a perfectly fine solution for me this time. Thanks for the quick response.