[New-bugs-announce] [issue34877] Inconsistent Behavior Of futures.ProcessPoolExecutor

[Tom Ashley]

New submission from Tom Ashley <tomashley at protonmail.com>:

Not sure if this goes in core or modules.

There is an inconsistency in the output of the attached script. From the docs I read it's supposed to have the behavior of:

"If something happens to one of the worker processes to cause it to exit unexpectedly, the ProcessPoolExecutor is considered “broken” and will no longer schedule tasks."

That script is supposed to exemplify that. Instead, if I run the code several times, I get the following output:

(bot-LP2ewIkY) ⋊> ~/w/p/b/bot on master ⨯ python brokenPool.py                                                                                                                                                                   18:54:55
getting the pid for one worker
killing process 4373
submitting another task
could not start new tasks: A process in the process pool was terminated abruptly while the future was running or pending.
(bot-LP2ewIkY) ⋊> ~/w/p/b/bot on master ⨯ python brokenPool.py                                                                                                                                                                   18:54:56
getting the pid for one worker
killing process 4443
submitting another task
could not start new tasks: A process in the process pool was terminated abruptly while the future was running or pending.
(bot-LP2ewIkY) ⋊> ~/w/p/b/bot on master ⨯ python brokenPool.py                                                                                                                                                                   18:54:57
getting the pid for one worker
killing process 4514
submitting another task  <----- (No exception thrown after this)


The exception isn't always thrown. This seems problematic to me. Related stack post: https://stackoverflow.com/questions/52617558/python-inconsistent-behavior-of-futures-processpoolexecutor

----------
components: Interpreter Core
files: brokenPool.py
messages: 326922
nosy: TensorTom
priority: normal
severity: normal
status: open
title: Inconsistent Behavior Of futures.ProcessPoolExecutor
versions: Python 3.7
Added file: https://bugs.python.org/file47843/brokenPool.py

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