bpo-37424: Avoid a hang in subprocess.run timeout output capture #14490
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When shell=True the user is often launching a process tree, if we kill only the shell and it hasn't set itself up as a pgrp leader, the grandchild processes still run and may have our output handles open. Leading us to wait forever when we should be timing out. This Adds a fractional timeout on the cleanup communicate phase _and_ will use killpg on the child process group _if_ it is different from our own as it should be when start_new_session=True was used.
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If an API change is made to make the default behavior easier for people in the future, that part won't get backported to 3.7. 3.8 only. |
gpshead
changed the title
giampaolo
reviewed
Jul 1, 2019
vstinner
reviewed
Jul 1, 2019
Do not have a post-timeout sub-timeout for output collection, we've already got all of that output within POSIX's _communicate() method as it is.
gpshead
commented
Jul 4, 2019
that belongs in its own PR if at all.
it wasn't actually testing what it described as it never checked the grandchild process explicitly. redo this better in a later PR.
Yhg1s
reviewed
Sep 10, 2019
miss-islington
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Sep 11, 2019
…honGH-14490) Fixes a possible hang when using a timeout on subprocess.run() while capturing output. If the child process spawned its own children or otherwise connected its stdout or stderr handles with another process, we could hang after the timeout was reached and our child was killed when attempting to read final output from the pipes. (cherry picked from commit 580d278) Co-authored-by: Gregory P. Smith <greg@krypto.org>
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GH-15897 is a backport of this pull request to the 3.8 branch. |
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GH-15898 is a backport of this pull request to the 3.7 branch. |
miss-islington
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Sep 11, 2019
…honGH-14490) Fixes a possible hang when using a timeout on subprocess.run() while capturing output. If the child process spawned its own children or otherwise connected its stdout or stderr handles with another process, we could hang after the timeout was reached and our child was killed when attempting to read final output from the pipes. (cherry picked from commit 580d278) Co-authored-by: Gregory P. Smith <greg@krypto.org>
miss-islington
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Sep 11, 2019
…14490) Fixes a possible hang when using a timeout on subprocess.run() while capturing output. If the child process spawned its own children or otherwise connected its stdout or stderr handles with another process, we could hang after the timeout was reached and our child was killed when attempting to read final output from the pipes. (cherry picked from commit 580d278) Co-authored-by: Gregory P. Smith <greg@krypto.org>
miss-islington
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Sep 11, 2019
…14490) Fixes a possible hang when using a timeout on subprocess.run() while capturing output. If the child process spawned its own children or otherwise connected its stdout or stderr handles with another process, we could hang after the timeout was reached and our child was killed when attempting to read final output from the pipes. (cherry picked from commit 580d278) Co-authored-by: Gregory P. Smith <greg@krypto.org>
websurfer5
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Jul 20, 2020
…honGH-14490) Fixes a possible hang when using a timeout on subprocess.run() while capturing output. If the child process spawned its own children or otherwise connected its stdout or stderr handles with another process, we could hang after the timeout was reached and our child was killed when attempting to read final output from the pipes.
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Fixes a possible hang when using a timeout on
subprocess.run()whilecapturing output. If the child process spawned its own children or otherwise
connected its stdout or stderr handles with another process, we could hang
after the timeout was reached and our child was killed when attempting to read
final output from the pipes.
https://bugs.python.org/issue37424