In some circumstance I like to run firefox as an other user. The way I used to do this was:
$ xhost +local:
$ sudo -u other-user firefox
However since my latest xubuntu upgrade which made firefox a snap application this no longer works. I get the following diagnostic
/user.slice/user-1003.slice/session-c2.scope is not a snap cgroup
That sounds like a problem that potentially affects all snaps, not just firefox. Could you file a bug against snapd and share the link here?
sudo doesn’t really set up a whole session, thus there’s no session bus, and no way to create a transient scope which is mandatory for application tracking, completing the sandbox and providing refresh app awareness. Especially on a fully cgroup v2 system, the only way device filtering can be implemented without breaking your session is using a separate cgroup (i.e. the transient scope).
perhaps using pkexec instead of sudo could work here (iirc it integrates wit logind so it might spawn enough of a session) ?
pkexec --user <username> <command>
No, that doesn’t work either:
$ pkexec --user <username> firefox
`/user.slice/user-1003.slice/session-c2.scope is not a snap cgroup`