Package: libclutter-gtk-1.0-0
Version: 1.8.4-4
Package: gnome-session-common
Version: 3.30.1-2
In short: When running a mate session the environment-variable CLUTTER_BACKEND=x11 is set. This variable survives a logout and relogin into the GNOME wayland-session, which doesn't override it. The
result is a bunch of not launchable clutter-gtk applications.
To reproduce the issue:
* Install debian 10.3.0 with gnome and mate environment
* Optional:
* Login into GNOME (wayland) Session
* Run `env | grep -Ei 'x11|wayland'`
XDG_SESSION_TYPE=wayland
WAYLAND_DISPLAY=wayland-0
* Note: CLUTTER_BACKEND is not set
* Launch `gnome-control-center` via graphical environment or console
* Works fine
* Logout
* Login into MATE session
* `env | grep -Ei 'x11|wayland'`
CLUTTER_BACKEND=x11
XDG_SESSION_TYPE=x11
* `sudo grep -Ri CLUTTER_BACKEND /etc/`
/etc/X11/Xsession.d/99mate-environment: export CLUTTER_BACKEND=x11
* Logout
* Login into GNOME (wayland) session
* `env | grep -Ei 'x11|wayland'`
CLUTTER_BACKEND=x11 # <- survived!
XDG_SESSION_TYPE=wayland
WAYLAND_DISPLAY=wayland-0
* Launch `gnome-control-center` via graphical environment or console
* Observe it doesn't startup
(gnome-control-center:4399): Clutter-Gtk-ERROR **: 12:23:42.914: ***
Unsupported backend.
* In fact all of the following apps terminate the same way
* `compgen -c | while read cmd; do [ -n "$(which $cmd)" ] && ldd $(which $cmd)
| grep -q clutter-gtk && echo $cmd; done`
cheese
totem
evolution
gnome-control-center
gnome-contacts
cheese
totem
evolution
gnome-control-center
gnome-contacts
gnome-nibbles
swell-foop
lightsoff
quadrapassel
* Now launch `CLUTTER_BACKEND=wayland gnome-control-center`
* Works fine
So I suppose the surviving of session-variables is the core issue here. In case of it beeng rather a feature than a bug, I suppose gnome should set CLUTTER_BACKEND explicitly aswell. Or maybe
clutter-gtk shall respect this constellation of CLUTTER_BACKEND and GDK_WAYLAND_DISPLAY?
