Troubles with declaring wayland-only session

Hi!

I was trying to set my NixOS Wayland only and I think I broke some things. Here is my config:

  services = {
    displayManager = {
      defaultSession = "plasma";
      sddm = {
        enable = true;
        wayland.enable = true;
      };
    };

When I run “nixos-rebuild switch --flake /etc/nixos#default” There is this error:

[root@dell-3:/home/kazimierzkrauze]# nixos-rebuild switch --flake /etc/nixos#default
building the system configuration...
evaluation warning: xdg-desktop-portal 1.17 reworked how portal implementations are loaded, you
                    should either set `xdg.portal.config` or `xdg.portal.configPackages`
                    to specify which portal backend to use for the requested interface.

                    https://github.com/flatpak/xdg-desktop-portal/blob/37a6f7c8b8e08b9861f05e172cd4e0d07a832c4d/doc/portals.conf.rst.in

                    If you simply want to keep the behaviour in < 1.17, which uses the first
                    portal implementation found in lexicographical order, use the following:

                    xdg.portal.config.common.default = "*";
error:
       … while calling the 'head' builtin
         at /nix/store/8fwsiv0hd7nw1brkvka0jf1frk3m7qkr-source/lib/attrsets.nix:1574:11:
         1573|         || pred here (elemAt values 1) (head values) then
         1574|           head values
             |           ^
         1575|         else

       … while evaluating the attribute 'value'
         at /nix/store/8fwsiv0hd7nw1brkvka0jf1frk3m7qkr-source/lib/modules.nix:846:9:
          845|     in warnDeprecation opt //
          846|       { value = addErrorContext "while evaluating the option `${showOption loc}':" value;
             |         ^
          847|         inherit (res.defsFinal') highestPrio;

       … while evaluating the option `system.build.toplevel':

       … while evaluating definitions from `/nix/store/8fwsiv0hd7nw1brkvka0jf1frk3m7qkr-source/nixos/modules/system/activation/top-level.nix':

       … while evaluating the option `system.systemBuilderArgs':

       … while evaluating definitions from `/nix/store/8fwsiv0hd7nw1brkvka0jf1frk3m7qkr-source/nixos/modules/system/activation/activatable-system.nix':

       … while evaluating the option `system.activationScripts.etc.text':

       … while evaluating definitions from `/nix/store/8fwsiv0hd7nw1brkvka0jf1frk3m7qkr-source/nixos/modules/system/etc/etc-activation.nix':

       … while evaluating definitions from `/nix/store/8fwsiv0hd7nw1brkvka0jf1frk3m7qkr-source/nixos/modules/system/etc/etc.nix':

       … while evaluating the option `environment.etc."sddm.conf".source':

       … while evaluating definitions from `/nix/store/8fwsiv0hd7nw1brkvka0jf1frk3m7qkr-source/nixos/modules/services/display-managers/sddm.nix':

       … while evaluating the option `services.displayManager.defaultSession':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: Default graphical session, 'plasma', not found.
       Valid names for 'services.displayManager.defaultSession' are:

[root@dell-3:/home/kazimierzkrauze]#

What bums me is why there aren’t any valid names suggested?

Can you guys help me?

Did you enable plasma?

No… Thank you, that worked:)