xscreensaver-settings fails to start on some window managers: X_SetInputFocus fails with BadMatch
We've had a report in Debian that xscreensaver-settings fails to start under some (but not all) X11 window managers as a result of what it seems might be a GDK/GTK error-handling issue.
To reproduce
- Boot debian-installer 12 alpha in a virtual machine
- At the menu, deselect the default GNOME desktop and choose XFCE instead (to rule out any Wayland involvement)
- Boot the installed system
- Install the
mwm
package - Log out from XFCE
- Log back in, choosing mwm in the lightdm menu
- Right-click on the background, Debian -> Applications -> Shells -> bash
- Run
xscreensaver-settings
I confirm that running xscreensaver-settings in XFCE does not exhibit this bug, but running it in mwm does.
Some relevant package versions for the versions I tested:
- libgtk-3-0 3.24.36-3 (in upstream terms this is basically 3.24.36-33-g5554113c from the gtk-3-24 branch, with fba09dbf applied as a patch)
- mwm 2.3.8-3
- xscreensaver 6.06+dfsg1-2
- xserver-xorg-core 2:21.1.7-1
The failing command can be run under a debugger with:
$ sudo apt install gdb
$ DEBUGINFOD_URLS=https://debuginfod.debian.net gdb `command -v xscreensaver-settings`