Major QDBus regression in Qt6 with potential impact on KDE

[Bartosz Golaszewski]

On Fri, Dec 16, 2022 at 10:39 PM Albert Astals Cid <aacid at kde.org> wrote:
>
> El divendres, 16 de desembre de 2022, a les 16:20:29 (CET), Bartosz
> Golaszewski va escriure:
> > On Fri, Dec 16, 2022 at 4:05 PM Albert Astals Cid <aacid at kde.org> wrote:
> > > El divendres, 16 de desembre de 2022, a les 15:45:17 (CET), Bartosz
> > >
> > > Golaszewski va escriure:
> > > > 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. :)
> > >
> > > Fair enough :)
> > >
> > > As a suggestion next time attach the code, don't put it in comments (and
> > > provide a full buildable example, yours doesn't have a buildsystem), makes
> > > me super sad that i have to copy and paste and i was almost super close
> > > to not even bothering trying it.
> >
> > What are you talking about, there's a link to my github repo at the
> > bottom and it includes requirements.txt for python and a .pro file for
> > Qt.
>
> For those that are not put off by his somewhat agressive manners and still want
> to invest their spare time to help him, the link to github repo is hidden in
> the "here" word of the "The examples I posted are available here." in a 250
> lines comment.
>

Albert,

Sorry, it was not my intention to come off as "aggressive". Sometimes
written communication doesn't correctly convey emotions, especially if
English is a second language.

Bart