Major QDBus regression in Qt6 with potential impact on KDE

[Bartosz Golaszewski]

On Fri, Dec 16, 2022 at 3:27 PM Albert Astals Cid <aacid at kde.org> wrote:
>
> El dijous, 15 de desembre de 2022, a les 19:55:59 (CET), Bartosz Golaszewski
> va escriure:
> > Hi!
> >
> > I'm working on a piece of software that extensively uses QDBus. The
> > project is based on Qt5. I'm trying to upgrade it to Qt6 but have
> > encountered an issue with QDBus that's described in detail in my
> > official bug report[1]. The report includes a link to a github repo
> > with reproducible examples.
> >
> > Short version is: it's impossible to connect to the InterfacesAdded or
> > InterfacesRemoved signals (and potentially to any signals that have
> > slightly more complex arguments) on the system bus with QDBus in Qt6
> > (unless one enables QDBUS_DEBUG=1 in which case it's possible). I
> > suspect some timing issue/race condition but don't know Qt enough to
> > debug it.
> >
> > While my project is not related to KDE, I thought I'd bring it to your
> > attention (as KDE is scheduled to upgrade to Qt6). This bug definitely
> > affects KDE as for instance the networkmanager-qt project subscribes
> > for the InterfacesAdded signal of NetworkManager's paths and will no
> > longer work with Qt6.
> >
> > Has anyone in the KDE community encountered this bug yet? How does KDE
> > deal with blockers like this? Seems like Qt is not eager to fix it on
> > their side.
>
> Remember Qt is Free Software, if you are blocked by it, you seem like a good
> person to try to fix it :)
>

Oh I tried and failed. :(

So instead I thought I'd find a) paying clients, b) projects with some
serious stake in QDBus that could help and report it to them in hope
of finding help. :)

Bart