$DISPLAY is wrong in resurrected session

[zori]

Hi, I've tried both with and without DISPLAY in the update-environment option:

set-option -g update-environment "DISPLAY SSH_ASKPASS SSH_AUTH_SOCK SSH_AGENT_PID SSH_CONNECTION WINDOWID XAUTHORITY"

Either way after rebooting my machine and attaching to a (resurrected) session, the DISPLAY variable is wrong (:0 while it should be :1).

I also use continuum, if that changes anything, with the following settings:

set -g @plugin 'tmux-plugins/tmux-continuum' # Continuous saving of tmux environment. https://github.com/tmux-plugins/tmux-continuum
set -g @continuum-save-interval '20' # Save the current session every 20 minutes
set -g @continuum-boot 'on'
set -g @continuum-restore 'on'

Any known work-arounds?

[chrischen]

Is that env variable updated while your session is running? Because as far as I know this plugin does not persist environment variables (though in my opinion it should).

You can try this plugin but you would have to probably bootstrap the variables back into the environment: #312.

[anindyaspaul]

I am facing the same issue with DISPLAY variable. The variable is updated using the following statement in .tmux.conf file.

set-option -g update-environment 'DISPLAY'

[atifraza]

I also experienced a similar issue with the DISPLAY environment variable although the variable is not being updated as per my knowledge.
The DISPLAY variable is properly set when SSHed into the server. The environment variable is properly set when creating a new tmux session/window/pane.
When the session is resurrected, the DISPLAY environment variable is empty in the resurrected windows/panes.
Although creating new windows/panes in the resurrected session imports the correct value of the environment variable.

[atifraza]

Update:

Apparently, my problem was possibly related to an outdated version of tmux.
I had tmux 1.9 running on a Debian Jessie server. Updating tmux to 2.3 resolved this issue for me.

[rcywongaa]

Issue is still happening. This is causing the resurrected vim's clipboard to not work and also making GUI applications fail

I tried the following to no avail.

run-shell 'DISPLAY=$(cat /proc/$(pgrep -u $USER "^gnome-shell$")/environ | tr "\0" "\n" | grep ^DISPLAY= | cut -d "=" -f 2)'

I believe the problem actually lies in tmux-continuum and not tmux-resurrect. tmux-continuum starts the tmux server before Gnome (or any user GUI). There is no way to know what the correct DISPLAY variable should be. (This is also because tmux is made to work in non-GUI environments as well)

In the end, I just had to remove the line

set -g @continuum-boot 'on'

and the DISPLAY variable was set correctly

[thevinchi]

I landed here while troubleshooting this, and I was determined to keep the continuum-boot functionality. If you're like me and just can't give it up, add the following to your .bashrc:

function tmux_env() {
  local line
  [[ -n $TMUX ]] || return 0
  while IFS= read -r line; do
    [[ ! $line =~ ^- ]] \
      && eval $(printf 'export %s=%q' "${line%%=*}" "${line#*=}") \
      || eval $(printf 'export %s=' "${line#*-}")
  done < <(command tmux showenv)
}

PROMPT_COMMAND="tmux_env${PROMPT_COMMAND:+;$PROMPT_COMMAND}"

This ensures that each time your prompt is generated, the results of tmux showenv are exported into your environment. The first time you attach to a resurrected session, and you land at a prompt, simply press enter and your environment will be loaded into the current pane.

When the tmux-server is started by systemd everything will still be unset in each of your panes when you attach for the first time, but the variables defined with set -g update-environment '...' are actually in the global environment if you run tmux showenv after you attach, but none of the resurrected panes will have them until you press enter.

This also handles unsetting by checking for results from tmux showenv that are prefixed with - to prune variables as needed.

Obviously, this is not perfect, but it works.

[AndisGrossteins]

@thevinchi, you're correct that the issue is caused by tmux-plugins/tmux-continuum.

There's an open issue tmux-plugins/tmux-continuum#127 and some related discussion in PR tmux-plugins/tmux-continuum#107 and a draft PR tmux-plugins/tmux-continuum#128.

If you don't need DISPLAY like on a server, it can be solved by editing the systemd user service:

systemctl edit --full --user tmux.service

Just comment out the Environment=DISPLAY=:0 line and the DISPLAY won't be set next time your user session starts.