greetd's tuigreet needs `/var/cache/tuigreet`

[wucke13]

Describe the bug

tuigreet requires /var/cache/tuigreet in order to store persistent information about the last session and user for the --remember* flags.

Steps To Reproduce

{pkgs, ... }: {
  services.greetd = {
    enable = true;
    settings = {
      default_session = {
          command = ''
            ${pkgs.greetd.tuigreet}/bin/tuigreet \
              --sessions /run/current-system/sw/share/wayland-sessions/:/run/current-system/sw/share/xsessions/ \
              --remember \
              --remember-user-session \
              --user-menu \
              --power-shutdown /run/current-system/systemd/bin/systemctl poweroff \
              --power-reboot /run/current-system/systemd/bin/systemctl reboot
          '';
        };
    };
  };
}

Expected behavior

tuigreet remembers the session I picked.

Additional context

Basically the same as tuigreet/tuigreet#33 .

My hotfix so far:

{... }: {
  systemd.tmpfiles.rules = [
    "d '/var/cache/tuigreet' - greeter greeter - -"
  ];
}

Notify maintainers

@luc65r
@ivar

Metadata

 - system: `"x86_64-linux"`
 - host os: `Linux 6.1.41, NixOS, 23.05 (Stoat), 23.05.20230808.7828754`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.13.3`
 - nixpkgs: `/etc/nix/inputs/nixpkgs`

[katexochen]

Pinging @queezle as greetd module maintainer.

I'm not sure about the best way to fix this. Maybe we can add CacheDirectory=tuigreet to the systemd unit of the greed module?