bpo-41568: Fix refleaks in zoneinfo subclasses #21907
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This was leaking a reference to the weak cache dictionary for every ZoneInfo subclass created.
The previous version of the code accidentally cleared the global ZONEINFO_STRONG_CACHE variable (and inducing `ZoneInfo` to create a new strong cache) on calls to a subclass's `clear_cache()`. This would not affect guaranteed behavior, but it's still not the right thing to do (and it caused reference leaks).
pablogsal
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Aug 17, 2020
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I can confirm that this works:
❯ ./python -m test test_zoneinfo -R :
0:00:00 load avg: 7.77 Run tests sequentially
0:00:00 load avg: 7.77 [1/1] test_zoneinfo
beginning 9 repetitions
123456789
.........
== Tests result: SUCCESS ==
1 test OK.
Total duration: 10.0 sec
Tests result: SUCCESS
and the fix LGTM
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Thanks @pganssle for the PR, and @pablogsal for merging it 🌮🎉.. I'm working now to backport this PR to: 3.9. |
miss-islington
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Aug 17, 2020
* Fix refleak in C module __init_subclass__ This was leaking a reference to the weak cache dictionary for every ZoneInfo subclass created. * Fix refleak in ZoneInfo subclass's clear_cache The previous version of the code accidentally cleared the global ZONEINFO_STRONG_CACHE variable (and inducing `ZoneInfo` to create a new strong cache) on calls to a subclass's `clear_cache()`. This would not affect guaranteed behavior, but it's still not the right thing to do (and it caused reference leaks). (cherry picked from commit c3dd7e4) Co-authored-by: Paul Ganssle <[email protected]>
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GH-21912 is a backport of this pull request to the 3.9 branch. |
miss-islington
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* Fix refleak in C module __init_subclass__ This was leaking a reference to the weak cache dictionary for every ZoneInfo subclass created. * Fix refleak in ZoneInfo subclass's clear_cache The previous version of the code accidentally cleared the global ZONEINFO_STRONG_CACHE variable (and inducing `ZoneInfo` to create a new strong cache) on calls to a subclass's `clear_cache()`. This would not affect guaranteed behavior, but it's still not the right thing to do (and it caused reference leaks). (cherry picked from commit c3dd7e4) Co-authored-by: Paul Ganssle <[email protected]>
shihai1991
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Aug 20, 2020
* Fix refleak in C module __init_subclass__ This was leaking a reference to the weak cache dictionary for every ZoneInfo subclass created. * Fix refleak in ZoneInfo subclass's clear_cache The previous version of the code accidentally cleared the global ZONEINFO_STRONG_CACHE variable (and inducing `ZoneInfo` to create a new strong cache) on calls to a subclass's `clear_cache()`. This would not affect guaranteed behavior, but it's still not the right thing to do (and it caused reference leaks).
xzy3
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Oct 18, 2020
* Fix refleak in C module __init_subclass__ This was leaking a reference to the weak cache dictionary for every ZoneInfo subclass created. * Fix refleak in ZoneInfo subclass's clear_cache The previous version of the code accidentally cleared the global ZONEINFO_STRONG_CACHE variable (and inducing `ZoneInfo` to create a new strong cache) on calls to a subclass's `clear_cache()`. This would not affect guaranteed behavior, but it's still not the right thing to do (and it caused reference leaks).
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There are two refleaks related to subclassing the C implementation of
ZoneInfo:__init_subclass__leaks a reference to the subclass's weak cache.ZoneinfoSubclass.clear_cache()incidentally setszoneinfo.ZoneInfo's pointer to its strong cache toNULL, thus leaking the old strong cache (and forcingZoneInfoto create a new one).This fixes both of these issues.
https://bugs.python.org/issue41568