Ubuntu
gnome-session package

Desktop snaps don't start at all in Xorg sessions if a Wayland session has been used

Bug #1965113 reported by Daniel van Vugt
10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Snapcraft
Incomplete
Undecided
Unassigned
gnome-session
New
Unknown
gnome-session (Ubuntu)
Triaged
Medium
Unassigned

Bug Description

Firefox 98.0.1-2 snap doesn't start at all in Xorg sessions.

$ /snap/bin/firefox
Error: cannot open display: :0

$ echo $DISPLAY
:0

And other X11 apps still work just fine.

Tags: jammy snap x11
Revision history for this message
Daniel van Vugt (vanvugt) wrote :

The tarball of the same release works just fine:

https://download-installer.cdn.mozilla.net/pub/firefox/releases/98.0.1/linux-x86_64/en-US/firefox-98.0.1.tar.bz2

Revision history for this message
Sebastien Bacher (seb128) wrote :

Could you share the output of

$ snap connections firefox

it's working fine here but could it be that somehow the x11 interface isn't connected for you?

Revision history for this message
Daniel van Vugt (vanvugt) wrote :

And today it just works.

Changed in firefox (Ubuntu):
status: New → Invalid
status: Invalid → New
Revision history for this message
Daniel van Vugt (vanvugt) wrote :

Failing again. It only fails in Xorg sessions after I've launched it in a Wayland session and then logged out.

1. Log into a Wayland session and launch Firefox.
2. Log into a Xorg session and Firefox can't start.

'snap connections firefox' shows as connected?;

  x11 firefox:x11 :x11

Rebooting fixes the problem. I can launch Firefox again.

summary: - Firefox 98.0.1-2 snap doesn't start at all in Xorg sessions
+ Firefox 98.0.1-2 snap doesn't start at all in Xorg sessions if a Wayland
+ session has been used
Revision history for this message
Olivier Tilloy (osomon) wrote : Re: Firefox 98.0.1-2 snap doesn't start at all in Xorg sessions if a Wayland session has been used

That's a known issue, see https://forum.snapcraft.io/t/cannot-open-display-after-session-type-changed-wayland-x11/23838. The problem appears to be partly in gnome-session (https://gitlab.gnome.org/GNOME/gnome-session/-/issues/75), partly in the snapcraft desktop extensions that assume a wayland session if there's a lingering wayland socket (https://github.com/snapcore/snapcraft/blob/main/extensions/desktop/common/desktop-exports#L240).

It is not specific to the firefox snap, and it can be worked around by running the apps with DISABLE_WAYLAND=1.

affects: firefox (Ubuntu) → gnome-session (Ubuntu)
summary: - Firefox 98.0.1-2 snap doesn't start at all in Xorg sessions if a Wayland
- session has been used
+ Desktop snaps don't start at all in Xorg sessions if a Wayland session
+ has been used
Daniel van Vugt (vanvugt)
Changed in gnome-session (Ubuntu):
importance: Undecided → Medium
Sebastien Bacher (seb128)
Changed in gnome-session (Ubuntu):
status: New → Triaged
Revision history for this message
Sergio Schvezov (sergiusens) wrote :

Is there a better way to detect a wayland session?

Changed in snapcraft:
status: New → Incomplete
Revision history for this message
Daniel van Vugt (vanvugt) wrote :

It looks like the presence of environment $WAYLAND_DISPLAY should work.

You can't rely on $DISPLAY to detect X11 because that exists in both Xorg and Wayland sessions thanks to Xwayland.

Bug Watch Updater (bug-watch-updater)
Changed in gnome-session:
status: Unknown → New
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