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asyncio.Runner+PidfdChildWatcher leaves zombie processes #95899
Description
import asyncio
import sys
import unittest
import asyncio
asyncio.set_child_watcher(asyncio.PidfdChildWatcher())
def create_free_port():
return 4 # chosen by a fair dice roll
class TestProc(unittest.IsolatedAsyncioTestCase):
async def asyncSetUp(self):
self.port = create_free_port()
self.proc = await asyncio.create_subprocess_exec(
sys.executable,
"-c", # more realistically this might be an http server or database
f"import time; print('listening on {self.port}'); import time; time.sleep(2); print('goodbye')",
)
async def testProc(self):
print(f"connecting to {self.port}")
async def asyncTearDown(self):
await self.proc.communicate() # hangs forever on 3.11
if __name__ == "__main__":
unittest.main()on python3.10 this produces:
connecting to 4
listening on 4
goodbye
.
----------------------------------------------------------------------
Ran 1 test in 2.022s
OK
on python3.11 it hangs forever in await self.proc.communicate()
Originally posted by @graingert in #95736 (comment)
Activity
graingert commentedon Aug 11, 2022
#94184 would fix this specific combination. I suspect any ChildWatcher that implements
attach_loopwould be broken[-]asyncio.Runner+PidFdChildWatcher leaves zombie processes[/-][+]asyncio.Runner+PidfdChildWatcher leaves zombie processes[/+]gvanrossum commentedon Aug 12, 2022
Why the nonsense with
self.port? It does not contribute to understanding the repro but adds useless detail that the reader has to understand before being able to ignore.pythonGH-95899: fix asyncio.Runner to call set_event_loop only once (p…
GH-95899: fix asyncio.Runner to call set_event_loop only once (#95900)
GH-95899: fix asyncio.Runner to call set_event_loop only once (GH-95900…