Plasma Wayland

[bkchr]

Motivation for this change

Adds support for starting Plasma under Wayland. However, it still requires the following patch to get it shown in SDDM:

diff --git a/nixos/modules/services/x11/display-managers/sddm.nix b/nixos/modules/services/x11/display-managers/sddm.nix
index 426b899586f..66e481bc6f5 100644
--- a/nixos/modules/services/x11/display-managers/sddm.nix
+++ b/nixos/modules/services/x11/display-managers/sddm.nix
@@ -58,6 +58,8 @@ let
 
     [Wayland]
     EnableHidpi=${if cfg.enableHidpi then "true" else "false"}
+    SessionCommand=${lib.getBin pkgs.sddm}/share/sddm/scripts/wayland-session
+    SessionDir=/etc/wayland
 
     ${optionalString cfg.autoLogin.enable ''
     [Autologin]
@@ -262,10 +264,21 @@ in
       home = "/var/lib/sddm";
       group = "sddm";
       uid = config.ids.uids.sddm;
+      extraGroups = [ "video" ];
     };
 
     environment.etc."sddm.conf".source = cfgFile;
 
+    environment.etc."wayland/plasma-wayland.desktop".text = ''
+      [Desktop Entry]
+      Encoding=UTF-8
+      Type=Application
+      Exec=/run/current-system/sw/bin/dbus-run-session ${lib.getBin pkgs.plasma-workspace}/bin/startplasmacompositor
+      TryExec=${lib.getBin pkgs.plasma-workspace}/bin/startplasmacompositor
+      DesktopNames=KDE
+      Name=Plasma-wayland
+    '';
+
     users.groups.sddm.gid = config.ids.gids.sddm;
 
     environment.systemPackages = [ sddm ];

CC @worldofpeace @adisbladis @peterhoeg

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Fits CONTRIBUTING.md.

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