Ctrl-C / SIGINT fails to cancel parent on first try

[goodboy]

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        = 2

Code 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.

[gsalgado]

I believe this has been fixed in one of my recent commits. Now, if I Ctrl-C the following script

trio.run(run_in_process, trio.sleep_forever)

I get this immediately:

^CTraceback (most recent call last):
  File "issue.py", line 5, in <module>
    trio.run(run_in_process, trio.sleep_forever)
  File "/home/salgado/virtualenvs/trio-rip/lib/python3.8/site-packages/trio/_core/_run.py", line 1896, in run
    raise runner.main_task_outcome.error
  File "/home/salgado/src/snakecharmers/trio-run-in-process/trio_run_in_process/run_in_process.py", line 125, in run_in_process
    return proc.get_result_or_raise()
  File "/home/salgado/src/snakecharmers/trio-run-in-process/trio_run_in_process/process.py", line 161, in get_result_or_raise
    raise self._error
trio.MultiError: KeyboardInterrupt(), KeyboardInterrupt()

Details of embedded exception 1:

  KeyboardInterrupt

Details of embedded exception 2:

  KeyboardInterrupt

[goodboy]

@gsalgado why don't you just prove it by merging the test in #5?

Also, what's with the necro-bump of this repo?

Aren't y'all doubling down on https://github.com/ethereum/aio-run-in-process ?