Question on typing Coroutines that return async generator "objects"

[ahnjaeshin]

I have a question on adding types to a function that returns async_generator object
Here's a simple snippet that carries the issue.

async def gen() -> AsyncGenerator[int, None]:
    for idx in range(100):
        yield idx

async def func():
    await asyncio.sleep(1)
    return gen()

generator = await func()
async for idx in generator:
    print(idx)

In the snippet above, what would be the return type of func?
Setting as AsyncGenerator seems weird cause you need an await keyword to get the generator.
And setting as Awaitable[AsyncGenerator] is also weird, as func itself is already a coroutine.

The reason func returns a async_coroutine object and not just iterate through it (async def func(): async for idx in gen(): ...) is that I wanted to make sure await asyncio.sleep gets called when the generator is created.

[hauntsaninja]

As it happens, also AsyncGenerator[int, None]! (Although, as in the sync world, you may wish to use AsyncIterator[int] in both cases)

See python/mypy#5070 and python/mypy#5385 for equivalent issues and explanation.