bug#35068: GDM crashes when it cannot find any .desktop files

[Ludovic Courtès]

Hello,

I used to have a config (when using SLiM) where my system profile did
not contain any window manager, so no .desktop files.  Instead, the WM
would be installed in my profile and ~/.xsession would start it and a
couple of other things.

Unfortunately GDM crashes in that context.  More precisely, after
choosing the user name on the log-in screen, it enters an infinite loop
with an assertion failure:

  gdm_session_set_environment_variable: assertion 'value != NULL' failed

At that point you pretty much have to reboot since it becomes very hard
to type at the console.  (You can try it in a VM.)

The workaround is to add at least one window manager to the system’s
‘packages’ field.

It would be nice to fix it now that GDM is our default log-in manager.

Ludo’.