How to Annotate Call Decorator with Fixed Position-only Arguments Followed by Arbitrary Arguments?

[MikuAuahDark]

Hello,

I need help on annotating a call decorator using param spec. It used to work with older version of pyright. However in 1.1.376, it fails type-checking. Pardon me if I did something wrong or this has been discussed before. If this is a bug in pyright, feel free to convert this dicussion into an issue.

This is a simplification on what I'm trying to do in a bigger project. So I have call decorator that accepts 1 argument to decorate a function with 2 fixed positional-only arguments, followed by additional arbitrary positional or keyword arguments.

This is my attempt:

# Filename: test_psec.py
import collections.abc

from typing import Protocol

class CallParam[**P](Protocol):
    def __call__(
        self, context: str, userid: int, /, *args: P.args, **kwds: P.kwargs
    ) -> collections.abc.Awaitable[str]: ...

def call_decorator(num_type: int, /):
    def wrapper0[**P](func: CallParam[P]):
        async def wrapper1(context: str, userid: int, /, *args: P.args, **kwargs: P.kwargs) -> str:
            return f"calling with num: {num_type}; " + await func(context, userid, *args, **kwargs)
        return wrapper1
    return wrapper0

@call_decorator(1)
async def call_num_type_1(context: str, userid: int, /):
    return f"{context} {userid} type 1"

@call_decorator(2)
async def call_num_type_2(context: str, userid: int, /, mul: int):
    return f"{context} {userid} = {userid * mul} type 2"

Then I have another Python file that uses call_num_* functions:

# Filename: main.py
import test_pspec

async def main():
    result = [
        await test_pspec.call_num_type_1("Hello", 12345),
        await test_pspec.call_num_type_2("World", 2531011, 214013),
    ]
    print("\n".join(result))

if __name__ == "__main__":
    import asyncio
    asyncio.run(main())

When I run pyright command-line to main.py file, I get these errors (actual program run as expected):

D:\omitted\project>pyright main.py
d:\omitted\project\main.py
  d:\omitted\project\main.py:6:15 - error: Arguments for ParamSpec "P@wrapper0" are missing (reportCallIssue)
  d:\omitted\project\main.py:7:60 - error: Expected 2 positional arguments (reportCallIssue)
2 errors, 0 warnings, 0 informations

The reason I'm unable to fix this is, if I merge main.py and test_pspec.py and run pyright on test_pspec.py, I get no errors. It only errors if they're in separate file.

Any pointers on how to do what I need? Or is this is a bug in pyright? Or is it impossible due to limitation in Python typing spec? I appreciate any inputs, thanks.

[erictraut]

Thanks for reporting. This is definitely a bug. Converting to a bug report.

[erictraut]

Here's the associated issue: #8779.