Switch to inspect.getcoroutinefunction() can break testing with unittest.mock.patch()

[mjpieters]

In v0.46.0, Starlette switched from asyncio.iscoroutinefunction() to inspect.iscoroutinefunction(). Unfortunately, the two functions are not quite equivalent, at least not when it comes to the object created by unittest.mock.patch() / unittest.mock.create_autospec() in all Python versions < 3.13:

import sys, asyncio, inspect
from unittest.mock import create_autospec

async def foo():
    pass

mock = create_autospec(foo)

print(sys.version_info[:2])  # (3, 12)
print(asyncio.iscoroutinefunction(mock))  # True
print(inspect.iscoroutinefunction(mock))  # False

Specifically this is python/cpython#94924, which has been fixed in Python 3.13 but has not been backported.

I found this because our tests started to fail after upgrading Starlette in one of our projects.

Could starlette make the switch conditional?

E.g.

if sys.version_info < (3.13):
    from asyncio import iscoroutinefunction
else:
    from inspect import iscoroutinefunction


def is_async_callable(obj: Any) -> Any:
    while isinstance(obj, functools.partial):
        obj = obj.func

    return iscoroutinefunction(obj) or (callable(obj) and iscoroutinefunction(obj.__call__))

[Kludex]

Yes, please.

[mjpieters]

Yes, please.

#2984