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Remove typing.AwaitableGenerator #13804
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I don't know the background, but mypy makes use of this, e.g. here https://github.com/python/mypy/blob/749f2584da9425173d68eb220db7e92aa13ad8ea/mypy/checkexpr.py#L6361-L6382
So I would say it's intentional :)
AwaitableGeneratorshould probably not exist in typeshed. It's a holdover from when mypy and typeshed were tightly coupled. Cf. python/mypy#8699 and python/mypy#8240.Reacted by Brian Schubert, Jelle Zijlstra and Alan Bogarin- changed the title
[-]Unused type variable in AwaitableGenerator[/-][+]Remove typing.AwaitableGenerator[/+]on Apr 7, 2025 I have a proposal for typing generator-based coroutines.
When using
yield fromwith atypes.CoroutineType, replaceAwaitableGeneratorwithGenerator.This is consistent with its runtime type
types.GeneratorType, prevents usingawaitif it is not decorated with@types.coroutine, andGeneratorhas existed since v3.5.Some drawbacks:
Extending linters’ functionality to determine the types involved in a coroutine foryield from.from __future__ import annotations import types import asyncio from collections.abc import Generator from typing import Any @types.coroutine def generator_a(): # () -> Generator[None, Any, None] yield None # @types.coroutine def generator_b() -> Generator[Any, Any, None]: yield from asyncio.sleep(1) # type: ignore[misc] # () -> AwaitableGenerator[Any, Any, None, Any] def generator_c(): yield from asyncio.sleep(1) async def test_awaitable() -> None: await generator_a() # ok await generator_b() # TypeError! without @coroutine await generator_c() # bad: no @coroutine mark
Taking advantage of the topic:
inspectcan detect these objects marked with@types.coroutineviainspect.isawaitable, but it lacks an introspection function specifically for them.def isgeneratorcoroutine(o: object) -> typing.TypeGuard[types.GeneratorType[Any, Any, Any]]: return inspect.isgenerator(o) and bool(o.gi_code.co_flags & inspect.CO_ITERABLE_COROUTINE)
While manipulating coroutines, I came across AwaitableGenerator. Everything was going well until I noticed it had four type parameters. So, I checked the code.
Apparently, they have an additional type variable
_S, which, to me, makes no sense since it's not used in the protocol.So, I want to know if this feature is intentional and if it has any use.
If not, I think it's appropriate to follow the
Generator[YieldT, SendT, ReturnT]structure because it is a generator but it supportsawait.Blocked by python/mypy#8240 and pyright.