Please note that new features which require additional configuration will usually not be considered. We are happy with the feature set of i3 and want to focus in fixing bugs instead. We do accept feature requests, however, and will evaluate whether the added benefit (clearly) outweighs the complexity it adds to i3.

Keep in mind that i3 provides a powerful way to interact with it through its IPC interface: https://i3wm.org/docs/ipc.html.

plasma-workspace also uses BindsTo=graphical-session.target: https://codesearch.debian.net/search?q=BindsTo%3Dgraphical-session

I think we’ll need to switch to starting the i3 session via systemd in order to fulfill this feature request. We can probably use || i3 as a fallback in the i3.desktop Exec= line to make this work on machines without systemd (these days most notably non-Linux systems like FreeBSD).

There is some background info in https://people.debian.org/~mpitt/systemd.conf-2016-graphical-session.pdf, though I’m not sure how relevant it is, given that it’s from 2016.

Pull requests for this change are welcome, but I most likely won’t work on this myself.

Are there any plans on doing this?
Unfortunately I don't really understand how user targets are triggered in systemd, but I've found a repository containing the necessary systemd target and service files, as well as an i3 start script.

Am I right in thinking these could easily be adapted to be included in i3 directly and Exec in the desktop file would be replaced with start-i3 || i3?

As I wrote previously:

Pull requests for this change are welcome, but I most likely won’t work on this myself.

This seems like a related discussion to me: https://pagure.io/i3-sig/Fedora-i3-Spin/issue/50 (see also the linked repo in that issue: https://github.com/alebastr/sway-systemd#session-target).

My very simple workaround is to have these unit files:

~/.config/systemd/user/i3-session.service:

[Unit]
Description=i3 window manager session
PartOf=i3-session.target
Wants=i3-session.target

# this service is started by i3 in its config file
# it's done like this so i3 and its launched child processes
# are not a service itself, but in the regular session scope.
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/true
Restart=on-failure

~/.config/systemd/user/i3-session.target:

# this target is wanted by i3-session.service (started by i3 config file)
[Unit]
Description=i3 Session
Requires=basic.target
BindsTo=graphical-session.target
Before=graphical-session.target

DefaultDependencies=no
RefuseManualStart=yes
RefuseManualStop=yes
Requires=basic.target
StopWhenUnneeded=yes

and finally, just start i3-session.service in your i3 config file:

exec --no-startup-id systemctl start --user i3-session.service

this works very well to start up the graphical session, but launched applications are not cgrouped yet.

the missing part is stopping the graphical session - I couldn't find a reliable way of stopping the graphical-session.target when i3 exits :)

if we had a exec --atexit systemctl stop --user graphical-session.target in i3 it could be enough for the first working version 🐱

Why not provide i3wm as a unit? and start it as part of the graphical-session.target?

Description=A tiling window manager for X11
After=plasma-kcminit.service
PartOf=graphical-session.target
Documentation=man:i3(1)

[Service]
ExecStart=/usr/bin/i3 --replace
ExecReload=/usr/bin/i3-msg restart
Slice=session.slice
Restart=on-failure

[Install]
Alias=plasma-kwin_x11.service
Alias=window-manager.service

^
Here's my unit. I use i3 with Plasma and override plasma-kwin_x11 (similar to using KDEWM=i3 in before systemd was used to start the session).

I think this way i3 is simply started as part of the graphical session.
The advantage being that the wm is also part of the session activation as it's on systemd service.
So for example the compositor can be started after the window-manager.
Any program that should start after i3 should have After=window-manager.service.
Remove the reference for non KDE use of course.

Also possible, but then all in-i3 started programs are part of the i3 service scope (cgroup). I want them to be part of the user slice session scope. One could also do this by having the launchers start new programs with systemd-run in the proper scope.

How would you do that? And with which launcher and config? :)