Bug#1100765: gnome-shell: `g_variant_get_string: assertion 'value != NULL' failed`

[Paul Menzel]

Package: gnome-shell
Version: 47.3-1
Severity: normal


Dear Debian folks,


Due to a regression [1], I downgraded from unstable to testing, and put 
*gnome-shell* on hold.

     run0 apt-mark hold gnome-shell

Now after working again, the user reported again the GNOME fail screen:

     Mär 18 11:27:41 laptop gnome-shell[973]: Running GNOME Shell (using 
mutter 47.4) as a Wayland display server
     Mär 18 11:27:42 laptop gnome-shell[973]: Thread 'KMS thread' will 
be using high priority scheduling
     Mär 18 11:27:42 laptop gnome-shell[973]: Device '/dev/dri/card0' 
prefers shadow buffer
     Mär 18 11:27:42 laptop gnome-shell[973]: Added device 
'/dev/dri/card0' (i915) using atomic mode setting.
     Mär 18 11:27:42 laptop gnome-shell[973]: Failed to initialize 
accelerated iGPU/dGPU framebuffer sharing: KMS CRTC doesn't support GBM 
format
     Mär 18 11:27:42 laptop gnome-shell[973]: Created gbm renderer for 
'/dev/dri/card0'
     Mär 18 11:27:42 laptop gnome-shell[973]: GPU /dev/dri/card0 
selected primary from builtin panel presence
     Mär 18 11:27:42 laptop gnome-shell[973]: Obtained a high priority 
EGL context
     Mär 18 11:27:43 laptop gnome-shell[973]: g_variant_get_string: 
assertion 'value != NULL' failed
     Mär 18 11:27:43 laptop gnome-shell[973]: == Stack trace for context 
0x56071af654b0 ==
     Mär 18 11:27:43 laptop gnome-shell[973]: The mapping function given 
to g_settings_get_mapped() for key 'overlay-key' in schema 
'org.gnome.mutter' returned FALSE when given a NULL value.
     Mär 18 11:27:43 laptop systemd-coredump[1013]: [🡕] Process 973 
(gnome-shell) of user 1001 dumped core.

                     laptop                          Stack trace of 
thread 973:
                     laptop                          #0 
0x00007ff395afd8ac n/a (n/a + 0x0)
                     laptop                          ELF object binary 
architecture: AMD x86-64
     Mär 18 11:27:43 laptop systemd[812]: 
org.gnome.Shell at wayland.service: Main process exited, code=dumped, 
status=5/TRAP
     Mär 18 11:27:43 laptop systemd[812]: 
org.gnome.Shell at wayland.service: Failed with result 'core-dump'.
     Mär 18 11:27:43 laptop systemd[812]: Failed to start 
org.gnome.Shell at wayland.service - GNOME Shell on Wayland.
     Mär 18 11:27:43 laptop systemd[812]: 
org.gnome.Shell at wayland.service: Consumed 817ms CPU time, 135.7M memory 
peak.

(The same with X11.)

Looking at the dpkg logs, *mutter-common* seems to have been upgraded to 
48~rc-4, that entered testing on March 14th.

Upgrading to the stack in the suite *unstable*, fixed the issue in the 
mean time, but it looks like more dependencies need to be denoted to 
prevent such a problem in the future.


Kind regards,

Paul


[1]: https://gitlab.gnome.org/GNOME/mutter/-/issues/3954