[New-bugs-announce] [issue40574] segfault causing regression from PEP 573 implementation

[Thomas Caswell]

New submission from Thomas Caswell <tcaswell at gmail.com>:

https://github.com/python/cpython/commit/e1becf46b4e3ba6d7d32ebf4bbd3e0804766a423 causes pyqt5 to segfault an accessing an attribute

To reproduce this:


pip install pyqt5
pip install sip
python -c "import PyQt5.QtCore; PyQt5.QtCore.Qt.Key_Control"  # this segfaults

Setting up faulthandler gives:

jupiter at 23:54  ➤  python -X faulthandler -c "import PyQt5.QtCore; PyQt5.QtCore.Qt.Key_Control"
Fatal Python error: Segmentation fault

Current thread 0x00007f52111cd740 (most recent call first):
<no Python frame>
Segmentation fault (core dumped)

It is likely that this should also be reported to riverbank as a pyqt/sip bug, but I'm starting here.  I apologize for not having a simpler reproducing case.




jupiter at 00:01  ➤ git bisect log
git bisect start
# good: [2d8757758d0d75882fef0fe0e3c74c4756b3e81e] bpo-40286: Remove C implementation of Random.randbytes() (GH-19797)
git bisect good 2d8757758d0d75882fef0fe0e3c74c4756b3e81e
# bad: [d10091aa171250c67a5079abfe26b8b3964ea39a] bpo-40502: Initialize n->n_col_offset (GH-19988)
git bisect bad d10091aa171250c67a5079abfe26b8b3964ea39a
# good: [c3f001461d5794c81cf5f70e08ae5435fe935ceb] bpo-40491: Fix typo in syntax error for numeric literals (GH-19893)
git bisect good c3f001461d5794c81cf5f70e08ae5435fe935ceb
# good: [c21c51235aa8061da6b0593d6f857f42fd92fd8b] bpo-40355: Improve error messages in ast.literal_eval with malformed Dict nodes (GH-19868)
git bisect good c21c51235aa8061da6b0593d6f857f42fd92fd8b
# good: [c1c7d8ead9eb214a6149a43e31a3213c52448877] bpo-40397: Refactor typing._GenericAlias (GH-19719)
git bisect good c1c7d8ead9eb214a6149a43e31a3213c52448877
# bad: [c068b53a0ca6ebf740d98e422569d2f705e54f93] bpo-38787: Update structures.rst docs (PEP 573) (GH-19980)
git bisect bad c068b53a0ca6ebf740d98e422569d2f705e54f93
# good: [4638c6429575bd6de26b12b2af5df74d6568b553] bpo-40334: Error message for invalid default args in function call (GH-19973)
git bisect good 4638c6429575bd6de26b12b2af5df74d6568b553
# bad: [8963a7f1f84a05412178b56629508b660d38861b] bpo-40545: Export _PyErr_GetTopmostException() function (GH-19978)
git bisect bad 8963a7f1f84a05412178b56629508b660d38861b
# bad: [e1becf46b4e3ba6d7d32ebf4bbd3e0804766a423] bpo-38787: C API for module state access from extension methods (PEP 573) (GH-19936)
git bisect bad e1becf46b4e3ba6d7d32ebf4bbd3e0804766a423
# first bad commit: [e1becf46b4e3ba6d7d32ebf4bbd3e0804766a423] bpo-38787: C API for module state access from extension methods (PEP 573) (GH-19936)

----------
components: C API
messages: 368499
nosy: tcaswell
priority: normal
severity: normal
status: open
title: segfault causing regression from PEP 573 implementation
versions: Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40574>
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