[issue12157] join method of multiprocessing Pool object hangs if iterable argument of pool.map is empty

[STINNER Victor]

STINNER Victor <victor.stinner at haypocalc.com> added the comment:

>Don't Try to use any fancy way to check if the join will hang,
> leave all the job to faulthandler.	

> Victor, do you agree with the simpler method, depending
> on faulthandler to catch a hang in the test and fail it?
> Or is the explicit timeout better?

If the patch fixes the hang, there is no good reason to write code to handle a new hang.

We have generic "watchdogs":

 - buildbot timeout (any Python version)
 - regrtest timeout implemented using faulthandler (only in Python 3.x)

If you run directly the .py test file on a command line, you can still use CTRL+c or CTRL+z to interrupt / stop the process.

You may want to improve these generic watchdogs, but write a specific watchdog for one specific test function looks useless to me.

Remember that timeouts are not reliable: we have sometimes false failures because of very slow buildbots... For regrtest timeout, I tried 10, 15, 20 and 30 minutes before choosing a timeout of 60 minutes. For lower values, we have many false failures.

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue12157>
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