Compositor handoff - switching compositor at runtime

[KAGEYAM4]

https://www.phoronix.com/news/Qt-6.6-QtWayland-Handoffs

Would it possible to support this where i can switch between Hyprland and KDE?

Edit: is it on hold because, most toolkit does not support surviving crash ?

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I wasn't even able to have dolphin survive the crash. Am i doing something wrong? Steps ->

1. wl-restart Hyprland
2. nohup dolphin &
3. btop++ and SIGKILL to Hyprland
   Compositor restart but dolphin died.

Do you know how to crash KDE, so i can test wether something is wrong with Hyprland or not.

[Ferdi265]

Yes, most toolkits don't support this yet. Qt5/6 supports compositor restarts if QT_WAYLAND_RECONNECT=1 is set in the environment. For more details, see the wl-restart man page and also The KDE docs on 'Restarting'.

Depending on what theming you use, surviving compositor crashes might also not work. QGnomePlatform theming for Qt apps previously caused compositor reconnect to break (due to use of GTK), but it seems that is no longer the case.

From my personal experience, Qt does pretty well at surviving crashes, Firefox at least tries to restart and displays the "firefox crashed" window, but other apps don't fare so well.

Switching between two different compositors with wl-restart could technically work, but would require integration in wl-restart (i.e., a way for you to change the run command between restarts).

[Ferdi265]

Do you know how to crash KDE, so i can test wether something is wrong with Hyprland or not.

the easiest way is to call killall -ILL kwin_wayland

[KAGEYAM4]

Yes, most toolkits don't support this yet. Qt5/6 supports compositor restarts if QT_WAYLAND_RECONNECT=1 is set in the environment. For more details, see the wl-restart man page and also The KDE docs on 'Restarting'.

QT_WAYLAND_RECONNECT=1 worked, i grossed over Toolkit support and didn't see this. It works now in Hyprland and KDE.

[Ferdi265]

Great! Should we leave this issue open as a tracking issue for switching compositor at runtime, or do you want to open a new issue for that?

[KAGEYAM4]

Great! Should we leave this issue open as a tracking issue for switching compositor at runtime, or do you want to open a new issue for that?

Lets keep this one, i have edited the title to be more descriptive.