[QGIS-Developer] [Qgis-psc] How to handle upstream Qt fixes

[Nyall Dawson]

On Sat, 4 Sept 2021 at 16:45, Ludovic Hirlimann <lhirlimann at 3liz.com> wrote:
>
> On 9/3/21 00:46, Nyall Dawson wrote:
> > Hi PSC, devs,
> >
> > I'd like to kick start some discussion on how best to handle the
> > situation with upstream Qt and their (lack of) support for Qt 5. As a
> > quick summary of the situation:
> >
> > - Qt Co effectively ended open source support of Qt 5 at the 5.15.2
> > release, and have moved all focus to Qt 6.
> > - While some preliminary work has been done, QGIS doesn't currently
> > support Qt 6 based builds, and likely won't be ready for this for some
> > time (even completely ignoring all the stable API questions a Qt 6
> > build raises entirely!)
>
> Wouldn't it be wiser to devote resources to moving to QT6 and do that
> faster than
> wait on potential unsuported 5x fixes ?

Well, getting QGIS to **build** on Qt 6 is at least another 3-4 weeks
work in my estimates (assuming someone worked full time on this.
Currently it's all done on volunteer time, so I'd estimate it's
another 6 months away at the current pace). And that's just getting it
to build. On the bits that have been ported so far (core + analysis)
we're seeing around 30% of tests failing. There's a LOT of work left
before QGIS will be usable on Qt 6.

Even if we got QGIS working nicely under Qt 6 there's still going to
be many users who are stuck on Qt 5 for the foreseeable future (e.g.
Debian/Ubuntu users), so we do need **some** plans on how to ensure
these users don't get left behind.

Nyall


>
>
> Ludovic
>
> --
> Administrateur Système Chez 3liz
> https://3liz.com solutions libre de Cartographie
> Système d'information Géographique // Developement QGIS
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>