Ahook class not compatible with passing 'firstresult=True' to a hookspec marker

[chevignon93]

When passing firstresult=True to a hookspec marker, the HookCaller will only return 1 result (coroutine) instead of a list of results but asyncio.gather expect a list of "tasks" and not a single coroutine

Here's a minimally reproducible example to illustrate the issue.

import apluggy
import asyncio

hookspec = apluggy.HookspecMarker("my-project")
hookimpl = apluggy.HookimplMarker("my-project")

class Hookspec:
    @hookspec(firstresult=True)
    async def afunc(self, x, y): ...

class Plugin:
    @hookimpl
    async def afunc(self, x, y):
        return x + y

async def main():
    pm = apluggy.PluginManager("my-project")
    pm.add_hookspecs(Hookspec())
    pm.register(Plugin)
    print(await pm.ahook.afunc(x=1, y=2))

asyncio.run(main())

The code above fails with TypeError: asyncio.tasks.gather() argument after * must be an iterable, not coroutine

but changing the call function to actually check whether calling hook(*args, **kwargs) returns a list and acting accordingly if it doesn't fixes the issue.

class AHook:
    def __init__(self, pm: PluginManager_) -> None:
        self.pm = pm

    def __getattr__(self, name: str) -> Callable[..., Coroutine[Any, Any, list]]:
        async def call(*args: Any, **kwargs: Any) -> list:
            hook: HookCaller = getattr(self.pm.hook, name)
            coros: list[asyncio.Future] = hook(*args, **kwargs)
            if not isinstance(coros, Coroutine):
                return None
            if not isinstance(coros, list):  # Added an isinstance check to see whether a list or a single element is returned
                return await coros
            return await asyncio.gather(*coros)
        return call

After this small change the code works as expected:

print(await pm.ahook.afunc(x=1, y=2))
>>> 3