Ctrl-C / SIGINT fails to cancel parent on first try #4
Description
What was wrong?
Trying to cancel a program with either ctrl-c or SIGINT results in the underlying subprocess(es) being cancelled but the parent hangs waiting requiring another of the same signal to be sent wherein the program errors with (if triggered from a pytest run):
value = <trio.Nursery object at 0x7fb3b01dedc0>
async def yield_(value=None):
> return await _yield_(value)
value = <trio.Nursery object at 0x7fb3b01dedc0>
env/lib/python3.8/site-packages/async_generator/_impl.py:106:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
env/lib/python3.8/site-packages/async_generator/_impl.py:99: in _yield_
return (yield _wrap(value))
tests/core/test_open_in_process.py:77: in test_open_in_proc_cancel_via_SIGINT
await trio.sleep_forever()
env/lib/python3.8/site-packages/async_generator/_util.py:53: in __aexit__
await self._agen.athrow(type, value, traceback)
trio_run_in_process/run_in_process.py:191: in open_in_process
nursery.cancel_scope.cancel()
env/lib/python3.8/site-packages/trio/_core/_run.py:725: in __aexit__
raise combined_error_from_nursery
trio_run_in_process/run_in_process.py:67: in _relay_signals
proc.send_signal(signum)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <trio_run_in_process.process.Process object at 0x7fb3b01debb0>, sig = 2
def send_signal(self, sig: int) -> None:
> os.kill(self.pid, sig)
E ProcessLookupError: [Errno 3] No such process
self = <trio_run_in_process.process.Process object at 0x7fb3b01debb0>
sig = 2Code that produced the error
I've submitted PR #5 as an addition to the test suite which demonstrates the issue(s).
Expected Result
Cancellation of both spawned subprocesses and the parent in the traditional trionic fashion.
I'm going to see what I can do to provide a fix for this. Imho this is an absolutely critical problem!
PS: on another note if you're looking for any collaborators on this project I'd be willing to throw in my hat. I'm extremely interested in a rock solid process launching library based around trio not only because I have a project based on this but also because I think a resilient process spawner is something the Python community needs in general.