Bug#1123020: tmux session does not survive logout

[Johannes Schauer Marin Rodrigues]

Package: gnome-session
Severity: normal

Hello Gnome maintainers,

steps to reproduce:

 * in gnome, start gnome-terminal
 * start tmux
 * detach from tmux (ctrl+B, D)
 * log out of gnome
 * log in to gnome with gdm
 * start gnome-terminal
 * run "tmux attach"

It will not find any sessions. I think this is unexpected behaviour. I raised
the issue today in #debian-devel IRC channel and a user reported an anecdote
that they were trying to be smart and ran "apt upgrade" inside tmux and then
logged out for safety. This killed their tmux session. I think it should be
expected that if programs like tmux or screen are started, they persist across
logins.

systemd/logind is currently built with -Ddefault-kill-user-processes=false to
enable exactly this use-case. Indeed when on the same machine I log in via a
tty, start tmux, detach, log out and then log in again, my tmux session is
still intact. Only when started under gnome is my tmux session not kept.

I'm a sway user and am also not affected by this issue.

I think that there should be no difference in the behaviour of tmux independent
on whether it's started in gnome, on a tty, via ssh or otherwise.

Please re-assign this bug as needed as I am not very familiar with the
Gnome ecosystem and the issue might be elsewhere.

Thank you for maintaining gnome in Debian!

cheers, josch