asyncio no longer supports generator-based coroutines in 3.12+ #10116
Description
What the title says.
On Python 3.11:
>python -m asyncio
asyncio REPL 3.11.2 (tags/v3.11.2:878ead1, Feb 7 2023, 16:38:35) [MSC v.1934 64 bit (AMD64)] on win32
Use "await" directly instead of "asyncio.run()".
Type "help", "copyright", "credits" or "license" for more information.
>>> import asyncio
>>> def foo():
... yield from []
...
>>> asyncio.create_task(foo())
<Task pending name='Task-1' coro=<foo() running at <console>:1>>
>>> exit()On Python 3.12:
>python -m asyncio
Running PGUpdate|x64 interpreter...
asyncio REPL 3.12.0a7+ (heads/main-dirty:79b9db9295, Apr 28 2023, 22:41:05) [MSC v.1932 64 bit (AMD64)] on win32
Use "await" directly instead of "asyncio.run()".
Type "help", "copyright", "credits" or "license" for more information.
>>> import asyncio
>>> def foo():
... yield from []
...
>>> asyncio.create_task(foo())
Traceback (most recent call last):
File "C:\Users\alexw\coding\cpython\Lib\concurrent\futures\_base.py", line 449, in result
return self.__get_result()
^^^^^^^^^^^^^^^^^^^
File "C:\Users\alexw\coding\cpython\Lib\concurrent\futures\_base.py", line 401, in __get_result
raise self._exception
File "C:\Users\alexw\coding\cpython\Lib\asyncio\__main__.py", line 34, in callback
coro = func()
^^^^^^
File "<console>", line 1, in <module>
File "C:\Users\alexw\coding\cpython\Lib\asyncio\tasks.py", line 377, in create_task
task = loop.create_task(coro)
^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\alexw\coding\cpython\Lib\asyncio\base_events.py", line 436, in create_task
task = tasks.Task(coro, loop=self, name=name, context=context)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: a coroutine was expected, got <generator object foo at 0x000001E6821AA200>@kumaraditya303 tells me that the same change has been made across asyncio on Python 3.12.
We'll need to change annotations like this:
typeshed/stdlib/asyncio/tasks.pyi
Lines 315 to 317 in 6f6b1c9
We should branch on sys.version_info, like this:
if sys.version_info >= (3, 12):
def create_task(
coro: Coroutine[Any, Any, _T], *, name: str | None = None, context: Context | None = None
) -> Task[_T]: ...
elif sys.version_info >= (3, 11):
def create_task(
coro: Generator[Any, None, _T] | Coroutine[Any, Any, _T], *, name: str | None = None, context: Context | None = None
) -> Task[_T]: ...
elif sys.version_info >= (3, 8):
# etc.We should probably make the change ASAP, so that people testing with the Python 3.12 betas get accurate type hints.