segfault using PyQt6 version 6.10.1

[Dmitry Shachnev]

Hi all,

On Sun, Dec 21, 2025 at 09:55:49PM +0100, Federico Bruni wrote:
> Hello
>
> Frescobaldi, an application using PyQt6, has recently hit a serious bug
> (causing a crash) which can be easily reproduced with PyQt 6.10.1,
> while version 6.10.0 works fine. In this link you can find some stack
> traces:
> https://github.com/frescobaldi/frescobaldi/issues/2126
>
> I noticed - unless I've done something wrong - that PyQt6 6.10.1 is
> using Qt 6.10.0 while PyQt6 6.10.0 is using Qt 6.10.1. Perhaps the bug
> we've found has been fixed already in Qt 6.10.1, but PyQt 6.10.1 is not
> using the last Qt6 version for some reasons.

Similar crashes (in QtWaylandClient::QWaylandClipboard::setMimeData) were
reported in Debian:

- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1123850
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1123860

And in Debian the Qt version is still 6.9.2, so it looks like a regression
in PyQt or SIP, not in Qt.

According to the reporter, downgrading PyQt from v6.10.1 to v6.10.0 helps.

PyQt v6.10.0 was built using SIP v6.14.0.
PyQt v6.10.1 was built using SIP v6.15.0 + commit 79da3321082f17d5 backported.

--
Dmitry Shachnev