[QGIS-Developer] qgis4 segfaults with qt6 6.11.0, ok with 6.10.2

[Sylvain POULAIN]

Hello, 

No problem on my side:
QGIS 4.0.2-Norrköping
Libraries
Version de Qt 6.11.0
Version de Python 3.14.4
GDAL version 3.12.4 — Chicoutimi
Version de Proj 9.8.1
Version de la base de données du registre EPSG v12.029 (2025-10-02)
Version de GEOS 3.14.1-CAPI-1.20.5
SFCGAL version 2.2.0
GeographicLib version Pas de support
Version de SQLite 3.53.0
Version de PDAL 2.9.3
Version du client PostgreSQL 18.3
Version de SpatiaLite 5.1.0
Version de QWT 6.3.0
Version de QScintilla2 2.14.1
Version de l'OS Manjaro Linux

echo $XDG_SESSION_TYPE
x11

No crash on opening a qgz/qgs project

Best regards,
---
Sylvain POULAIN 


> Le 13/05/2026 16:23 +04, Greg Troxel via QGIS-Developer <qgis-developer at lists.osgeo.org> a écrit :
> 
>  
> Richard Duivenvoorde <rdmailings at duif.net> writes:
> 
> > I've succesfully compiled and ran QGIS4 with Qt 6.9.2 and 6.10.2 as those are available in Debian Testing.
> 
> 4.0.0 and 4.0.2+18 both work with 6.10.2, except that they fail to find
> the authentication provider.  I suspect the authentication provider
> problem is about some qt6 part not being in pkgsrc yet.
> 
> > I think I've heard there were some issues with opening older project
> > files in QGIS4, but as Qt6.10 is working that is probably not the
> > issue here?
> 
> 4.0.2+18/6.10.2 will open a project file and act normally while
> 4.0.2+18/6.11.0 crashes on the same file.
> 
> Starting without a project file is ok.
> 
> Other complicated qt6-using programs work with 6.11.0 (on
> NetBSD-current), according to others.
> 
> > Can you create an issue maybe, preferably with a gdb trace on a debug
> > build? Hopefully core devs have a clue then?
> 
> I see from Andrea that osgeo4w has 4.0.2 with Qt 6.11.0, but I wonder
> 
>   does it work :-) ?
> 
>   surely that uses some different implementations than on POSIX, so
>   while it's a very helpful data point, I'm not sure what I can
>   conclude.
> 
> I should mention that I'm using X11 (which I've been using since I
> upgraded from X10!), given the "wayland is the answer, what was the
> question" problems in some corners of the GNU/Linux world.
> 
> Has anyone run qgis 4 with 6.11.x on POSIX with X11?
> 
> Overnight, pkgsrc got qt6 6.11.1, changelog "bugfixes".  I am updating
> and will rebuild all and see how it goes.  If still not ok, I'll flip to
> debug builds and build qt6 and qgis again, so gdb can get better
> backtraces, and file an issue.
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