Better to_thread()

[rafalkrupinski]

Hi, any chance to include a better to_thread?

The original loses all typing information, and doesn't allow any own parameters.

This version is fully typed (can be backported to older typing syntax), and separates the target function params from its own (if it ever has any)

def to_thread2[**P, R](fn: Callable[P, R]) -> Callable[P, Coroutine[None, None, R]]:

    @functools.wraps(fn)
    async def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
        return await asyncio.to_thread(fn, *args, **kwargs)

    return wrapper

usage:

#sync
def sync_fn(some_arg: str)-> str:
  pass

await to_thread2(sync_fn)('hello world')

#or

async_fn = to_thread2(sync_fn) #mypy, IDE can check signature

await async_fn('hello world')

@maxfischer2781

[maxfischer2781]

Thanks for the suggestion. However, asyncstdlib is intentionally agnostic to the async framework – it won't include any code specific to asyncio.

Note that if the type annotations for the standard library are lacking, the typeshed library is the place to suggest fixes. As far as I can tell, the current version already preserves typing information, though.