[Qgis-psc] Qt6 status

[Mathieu Pellerin]

With regards to the timeline question raised by Marco in this thread, I'd
like to add a +1 to the idea of postponing QGIS 4.0. At the very least, I
think we should make a conscious decision about it sooner than later :)

While we should all be very proud of the regular release interval
discipline we've shown in recent years, I think several factors warrant at
least seriously considering delaying QGIS 4.0.

Like Matthias, I believe the fact that a Qt6-based development environment
not adding a *considerable* amount of time spent building not having been
unlocked yet means most of our developers are still on Qt5. On my end, I
did try to switch to a Qt6-only development environment during the last
freeze period, only to find myself going back to Qt5 to retain an
acceptable build wait time. While we have had Qt6-based CI testing going on
for a while and being improved week after week, I would feel really
insecure shipping QGIS 4.0 with Qt6 libraries when most devs have not spent
a fair amount of time running Qt6 builds (both as part of their development
as well as mapping production environments). We're also a few weeks away
from bug fixing, and we risk entering it with developers still fixing bugs
against Qt5 libraries (because it's that much more efficient).

On top of what has been raised above, something less crucial but that is
still worth factoring in: we had a couple of interesting changes we wanted
to push into QGIS 4.0 which at the moment are increasingly at risk of not
making it into an October release date. For example, at this moment in
time, I'm certain the icons set revamp proposition can't be achieved in
time. It'd be good to hear the status of other important changes like the
welcome screen revamp.

Beyond that, thanks for the status updates and ongoing efforts to all
involved! Keen to hear what others have to say about this.

Mathieu



On Fri, Aug 22, 2025 at 10:30 PM Matthias Kuhn via QGIS-PSC <
qgis-psc at lists.osgeo.org> wrote:

> Hi all,
>
> Nice to see the progress on the ci front, thanks Nyall.
> The Qt6 packages for Windows and macOS are also ready to be tested as well
> (thanks Jürgen).
>
> I suspect many developers do most of their work with Qt5 (because it's
> more efficient looking at the build times) and therefore most testing by
> core developers and technical people is done on Qt5 builds.
> One thing that could help is to change the default to BUILD_WITH_QT6 as
> soon as possible and collect some low hanging fruits.
>
> With the feature freeze less than 3 weeks in front of us and the release
> in about two months, I think it's a good point to check if we are on track
> with the timeline or if we want to consider an adjustment as pointed out by
> Marco earlier in this thread.
>
> Cheers
> Matthias
>
> On Fri, Aug 22, 2025 at 9:11 AM Alessandro Pasotti via QGIS-PSC <
> qgis-psc at lists.osgeo.org> wrote:
>
>> I am currently on vacation but I will have a look next week.
>>
>> Kind regards
>>
>> --
>> Alessandro Pasotti
>> QCooperative:  www.qcooperative.net
>> ItOpen:   www.itopen.it
>>
>> Il gio 21 ago 2025, 11:22 Marco Bernasocchi via QGIS-PSC <
>> qgis-psc at lists.osgeo.org> ha scritto:
>>
>>> Thanks Nyall for the work and answer.
>>> on the other two points,
>>>
>>> - having some solution for the extremely slow sip build times on qt6
>>>
>>> Martin, do you have an ETA for David's grant https://github.com/qgis/QGIS-Enhancement-Proposals/pull/338
>>>
>>> - porting the ogc server ci to qt6
>>> Alessandro, would that be something you'd be willing/would have time ressources to take over since you worked a lot on the server in the past?
>>>
>>>
>>> it would be great if we can move all this forward so we can come closer to a qgis 4.0.
>>>
>>> I'd also would like to re ask if we should start preparing for a 1(x?) month delay for the freeze? And remember that there are funding available.
>>>
>>> Cheers
>>>
>>> Marco
>>>
>>>
>>> On Fri, 8 Aug 2025 at 05:22, Nyall Dawson <nyall.dawson at gmail.com>
>>> wrote:
>>>
>>>> On Fri, 8 Aug 2025 at 04:11, Marco Bernasocchi <marco at qgis.org> wrote:
>>>> >
>>>> > Hi all,
>>>> > I was just pointed to this mail
>>>> >
>>>> https://lists.osgeo.org/pipermail/qgis-developer/2025-July/067716.html
>>>> > and noticed that Nyall mentions some still needed work.
>>>> >
>>>> > @Nyall, do you think the freeze in 5 weeks is realistic? Do we need
>>>> to plan/prepare something different?
>>>> >
>>>> > Please, all developer involved in moving to Qt6, that the psc still
>>>> has reserved funding for this.
>>>>
>>>>  - porting the Ubuntu ci infrastructure to qt6, including the database
>>>> server based tests
>>>>
>>>> I'm currently working on this -- see
>>>> https://github.com/qgis/QGIS/pull/62809
>>>>
>>>> Nyall
>>>>
>>>>
>>>>
>>>> >
>>>> > Cheers Marco
>>>> >
>>>> > --
>>>> > Marco Bernasocchi
>>>> >
>>>> > QGIS.org Chair
>>>> > OSGEO.org VP Europe
>>>> > OPENGIS.ch CEO
>>>> > http://berna.io
>>>>
>>>
>>>
>>> --
>>> Marco Bernasocchi
>>>
>>> QGIS.org Chair
>>> OSGEO.org VP Europe
>>> OPENGIS.ch CEO
>>> http://berna.io
>>> _______________________________________________
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>>> QGIS-PSC at lists.osgeo.org
>>> https://lists.osgeo.org/mailman/listinfo/qgis-psc
>>>
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