Starting i3 gives "Cannot open display"

[samsnori]

After installing lidm and enabling it via the systemd service, I get an error "Cannot open display" when I try to login into a i3 session.

When I run startx w/o lidm everything works fine.

Is there anything I need to configure to make this work with i3?

[javalsai]

So apparently the .desktop files in /usr/share/xsessions need the xorg server to be running too. I think the "easiest" way to do that is to just offload that to startx and call the program.

But the i3's .desktop file just contains i3 on the Exec= key, opposed to gnome which contains /usr/bin/gnome-session. And startx seems to require a full path (there's not even a flag for path search that I found).

This can be considered a bug with lidm and now I get why xorg developers want to move away from it even better. I really don't know what the correct approach to this would be. One thing that crosses my mind is to check if the Exec= value is an absolute path to a binary and call startx with that or look the name up in $PATH and pass the found binary to startx. Idk much about xorg, does that look correct?

Also on a sidenote, this will of course be a million times worse in the nix package thanks to modularity but I'll get into that in the future.