gh-129195: use future_add_to_awaited_by/future_discard_from_awaited_by in asyncio.staggered.staggered_race #129253
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…ited_by in staggered race
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| """ | ||
| # TODO: when we have aiter() and anext(), allow async iterables in coro_fns. | ||
| loop = loop or events.get_running_loop() | ||
| parent_task = tasks.current_task(loop) |
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What happens if we're not running in a task? Should we assert that this is non-None?
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one possible outcome is that there's no task or running loop:
import asyncio.staggered
async def main():
async def asyncfn():
pass
await asyncio.staggered.staggered_race([asyncfn, asyncfn], delay=None)
main().__await__().send(None)we get a nice traceback, saying that:
./python demo.py
Traceback (most recent call last):
File "/home/graingert/projects/cpython/demo.py", line 9, in <module>
main().__await__().send(None)
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/home/graingert/projects/cpython/demo.py", line 7, in main
await asyncio.staggered.staggered_race([asyncfn, asyncfn], delay=None)
File "/home/graingert/projects/cpython/Lib/asyncio/staggered.py", line 66, in staggered_race
loop = loop or events.get_running_loop()
~~~~~~~~~~~~~~~~~~~~~~~^^
RuntimeError: no running event loopThere was a problem hiding this comment.
if you manually pass a loop, and step the coroutine outside of a task:
import asyncio.staggered
async def main(loop):
async def asyncfn():
print("hello")
await asyncio.staggered.staggered_race([asyncfn, asyncfn], delay=None, loop=loop)
return "world"
loop = asyncio.EventLoop()
coro = main(loop).__await__()
f = coro.send(None)
loop.run_until_complete(f)
try:
coro.send(None)
except StopIteration as e:
print(e.value)by some miracle it all works, this is because future_add_to_awaited_by and future_discard_from_awaited_by is noop if any arg is not a future (eg is None) and we don't have any further use of the parent task
./python demo.py
hello
worldso we should probably leave it like that.
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I don't think it's worth testing this usecase though
| t.cancel() | ||
|
|
||
| propagate_cancellation_error = None | ||
| try: |
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Above this--for cancelling all the coroutines, future_discard_from_awaited_by should get called, right?
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Yeah add_done_callback callbacks are called on cancellation, so it will get called
Misc/NEWS.d/next/Library/2025-01-24-10-48-32.gh-issue-129195.89d5NU.rst
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…9d5NU.rst Co-authored-by: Kumar Aditya <[email protected]>
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