Issue 15756: subprocess.poll() does not handle errno.ECHILD "No child processes" (original) (raw)

Issue15756

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This issue has been migrated to GitHub: https://github.com/python/cpython/issues/59960

classification

process

Created on 2012-08-21 19:15 by twhitema, last changed 2022-04-11 14:57 by admin. This issue is now closed.

Messages (5)
msg168798 - (view)	Author: Todd Whiteman (twhitema)	Date: 2012-08-21 19:15
In the case of a "errno.ECHILD" exception - Python's subprocess module misses the fact that the process has already ended. The following code will wait indefinitely, even though the launched process is quickly ended: import subprocess, signal signal.signal(signal.SIGCLD, signal.SIG_IGN) p = subprocess.Popen(['echo','foo']) while p.poll() is None: pass # wait for the process to exit Note: This is the exact same issue as , but applying to the subprocess.poll() method instead of the subprocess.wait() method.
msg168799 - (view)	Author: Todd Whiteman (twhitema)	Date: 2012-08-21 19:20
The attached patch handles errno.ECHILD in the _internal_poll() method and I've updated the existing "sigchild_ignore.py" test file to perform polling as well. An unpatched version of Pyhton would normally hang on this particular test, whilst the patched version will run successfully.
msg169581 - (view)	Author: Gregory P. Smith (gregory.p.smith) *	Date: 2012-08-31 20:38
thanks! I'll take care of getting this fix in.
msg171588 - (view)	Author: Roundup Robot (python-dev)	Date: 2012-09-29 18:58
New changeset 484c50bf445c by Gregory P. Smith in branch '3.2': Fixes issue #15756: subprocess.poll() now properly handles errno.ECHILD http://hg.python.org/cpython/rev/484c50bf445c New changeset ba8d85552e34 by Gregory P. Smith in branch '3.3': Fixes issue #15756: subprocess.poll() now properly handles errno.ECHILD http://hg.python.org/cpython/rev/ba8d85552e34 New changeset 9032b3f52819 by Gregory P. Smith in branch 'default': Fixes issue #15756: subprocess.poll() now properly handles errno.ECHILD to http://hg.python.org/cpython/rev/9032b3f52819
msg171589 - (view)	Author: Roundup Robot (python-dev)	Date: 2012-09-29 19:03
New changeset 53e91fa35f8e by Gregory P. Smith in branch '2.7': Issue #15756: subprocess.poll() now properly handles errno.ECHILD to http://hg.python.org/cpython/rev/53e91fa35f8e