[New-bugs-announce] [issue37261] test_io leaks references on AMD64 Fedora Rawhide Refleaks 3.8
STINNER Victor
report at bugs.python.org
Wed Jun 12 21:43:10 EDT 2019
New submission from STINNER Victor <vstinner at redhat.com>:
test_io leaks references on AMD64 Fedora Rawhide Refleaks 3.8:
https://buildbot.python.org/all/#/builders/229/builds/10
test_io leaked [23208, 23204, 23208] references, sum=69620
test_io leaked [7657, 7655, 7657] memory blocks, sum=22969
The issue has been introduced by my change:
commit c15a682603a47f5aef5025f6a2e3babb699273d6
Author: Victor Stinner <vstinner at redhat.com>
Date: Thu Jun 13 00:23:49 2019 +0200
bpo-37223: test_io: silence destructor errors (GH-14031)
* bpo-18748: Fix _pyio.IOBase destructor (closed case) (GH-13952)
_pyio.IOBase destructor now does nothing if getting the closed
attribute fails to better mimick _io.IOBase finalizer.
(cherry picked from commit 4f6f7c5a611905fb6b81671547f268c226bc646a)
* bpo-37223: test_io: silence destructor errors (GH-13954)
Implement also MockNonBlockWriterIO.seek() method.
(cherry picked from commit b589cef9c4dada2fb84ce0fae5040ecf16d9d5ef)
* bpo-37223, test_io: silence last 'Exception ignored in:' (GH-14029)
Use catch_unraisable_exception() to ignore 'Exception ignored in:'
error when the internal BufferedWriter of the BufferedRWPair is
destroyed. The C implementation doesn't give access to the
internal BufferedWriter, so just ignore the warning instead.
(cherry picked from commit 913fa1c8245d1cde6edb4254f4fb965cc91786ef)
It seems like the root issue is the usage of catch_unraisable_exception() in test_io.
class catch_unraisable_exception:
def __init__(self):
self.unraisable = None
self._old_hook = None
def _hook(self, unraisable):
self.unraisable = unraisable
def __enter__(self):
self._old_hook = sys.unraisablehook
sys.unraisablehook = self._hook
return self
def __exit__(self, *exc_info):
# Clear the unraisable exception to explicitly break a reference cycle
del self.unraisable
sys.unraisablehook = self._old_hook
*Sometimes* "del self.unraisable" of __exit__() triggers a new unraisable exception which calls again the _hook() method which sets again the unraisable attribute.
catch_unraisable_exception resurects _io.BufferedWriter objects, and then "del self.unraisable" calls again their finalizer: iobase_finalize() is called again, and iobase_finalize() calls PyErr_WriteUnraisable() on close() failure.
----------
messages: 345449
nosy: vstinner
priority: normal
severity: normal
status: open
title: test_io leaks references on AMD64 Fedora Rawhide Refleaks 3.8
versions: Python 3.8
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<https://bugs.python.org/issue37261>
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