Crash on deleting Element attribute

[serhiy-storchaka]

BPO	25691
Nosy	@scoder, @larryhastings, @vadmium, @serhiy-storchaka
Files	etree_del_attributes.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2015-11-23.07:01:10.423>
created_at = <Date 2015-11-21.17:04:39.640>
labels = ['extension-modules', 'type-crash']
title = 'Crash on deleting Element attribute'
updated_at = <Date 2015-11-23.07:28:15.898>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2015-11-23.07:28:15.898>
actor = 'larry'
assignee = 'none'
closed = True
closed_date = <Date 2015-11-23.07:01:10.423>
closer = 'serhiy.storchaka'
components = ['Extension Modules']
creation = <Date 2015-11-21.17:04:39.640>
creator = 'serhiy.storchaka'
dependencies = []
files = ['41114']
hgrepos = []
issue_num = 25691
keywords = ['patch']
message_count = 5.0
messages = ['255063', '255125', '255129', '255132', '255134']
nosy_count = 6.0
nosy_names = ['scoder', 'larry', 'eli.bendersky', 'python-dev', 'martin.panter', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue25691'
versions = ['Python 3.3', 'Python 3.4', 'Python 3.5']

[serhiy-storchaka]

>>> import xml.etree.ElementTree as ET
>>> e = ET.Element('tag')
>>> del e.tag
Segmentation fault (core dumped)

Proposed patch fixes the crash.

[vadmium]

The patch looks good to me.

This may be a side effect of poor documentation. I guess the documentation at <https://docs.python.org/dev/c-api/typeobj.html#c.PyTypeObject.tp_setattro\> and/or the referenced functions should mention that the they also delete attributes when the name argument is null.

[python-dev]

New changeset 852c9ed9115c by Serhiy Storchaka in branch '3.4':
Issue bpo-25691: Fixed crash on deleting ElementTree.Element attributes.
https://hg.python.org/cpython/rev/852c9ed9115c

New changeset 3a44f06907f1 by Serhiy Storchaka in branch '3.5':
Issue bpo-25691: Fixed crash on deleting ElementTree.Element attributes.
https://hg.python.org/cpython/rev/3a44f06907f1

New changeset 936fcd0ba6b1 by Serhiy Storchaka in branch 'default':
Issue bpo-25691: Fixed crash on deleting ElementTree.Element attributes.
https://hg.python.org/cpython/rev/936fcd0ba6b1

New changeset e3dea2e4f93d by Serhiy Storchaka in branch '2.7':
Issue bpo-25691: Added tests on deleting cElementTree.Element attributes.
https://hg.python.org/cpython/rev/e3dea2e4f93d

[serhiy-storchaka]

Thank you for your review Martin. Opened bpo-25701 for documenting.

Interestingly, 2.7 is free from this bug. It has a check for NULL.

[larryhastings]

This change didn't make it into 3.5.1. It will be released with 3.5.2. I've already updated the Misc/NEWS entry.