nixos/uwsm: set default for waylandCompositors (#474174)

nixos/modules/programs/wayland/hyprland.nix

@@ -89,6 +89,9 @@ in
           configPackages = lib.mkDefault [ cfg.package ];
         };
 
+        # To make the Hyprland session available in DM
+        services.displayManager.sessionPackages = [ cfg.package ];
+
         systemd = lib.mkIf cfg.systemd.setPath.enable {
           user.extraConfig = ''
             DefaultEnvironment="PATH=/run/wrappers/bin:/etc/profiles/per-user/%u/bin:/nix/var/nix/profiles/default/bin:/run/current-system/sw/bin:$PATH"
@@ -98,18 +101,6 @@ in
 
       (lib.mkIf (cfg.withUWSM) {
         programs.uwsm.enable = true;
-        # Configure UWSM to launch Hyprland from a display manager like SDDM
-        programs.uwsm.waylandCompositors = {
-          hyprland = {
-            prettyName = "Hyprland";
-            comment = "Hyprland compositor managed by UWSM";
-            binPath = "/run/current-system/sw/bin/start-hyprland";
-          };
-        };
-      })
-      (lib.mkIf (!cfg.withUWSM) {
-        # To make a vanilla Hyprland session available in DM
-        services.displayManager.sessionPackages = [ cfg.package ];
       })
 
       (import ./wayland-session.nix {

nixos/modules/programs/wayland/uwsm.nix

@@ -107,33 +107,39 @@ in
           binPath = "/run/current-system/sw/bin/sway";
         };
       '';
+      default = { };
     };
   };
 
-  config = lib.mkIf cfg.enable {
-    environment.systemPackages = [ cfg.package ];
-    systemd.packages = [ cfg.package ];
-    environment.pathsToLink = [ "/share/uwsm" ];
+  config = lib.mkIf cfg.enable (
+    lib.mkMerge [
+      {
+        environment.systemPackages = [ cfg.package ];
+        systemd.packages = [ cfg.package ];
+        environment.pathsToLink = [ "/share/uwsm" ];
 
-    # UWSM recommends dbus broker for better compatibility
-    services.dbus.implementation = "broker";
+        # UWSM recommends dbus broker for better compatibility
+        services.dbus.implementation = "broker";
 
-    services.displayManager = {
-      enable = true;
-      sessionPackages = lib.mapAttrsToList (
-        name: value:
-        mk_uwsm_desktop_entry {
-          inherit name;
-          inherit (value)
-            prettyName
-            comment
-            binPath
-            extraArgs
-            ;
-        }
-      ) cfg.waylandCompositors;
-    };
-  };
+        services.displayManager.enable = true;
+      }
+
+      (lib.mkIf (cfg.waylandCompositors != { }) {
+        services.displayManager.sessionPackages = lib.mapAttrsToList (
+          name: value:
+          mk_uwsm_desktop_entry {
+            inherit name;
+            inherit (value)
+              prettyName
+              comment
+              binPath
+              extraArgs
+              ;
+          }
+        ) cfg.waylandCompositors;
+      })
+    ]
+  );
 
   meta.maintainers = with lib.maintainers; [
     johnrtitor

pkgs/by-name/hy/hyprland/package.nix

@@ -194,7 +194,7 @@ customStdenv.mkDerivation (finalAttrs: {
     "NO_XWAYLAND" = !enableXWayland;
     "NO_SYSTEMD" = !withSystemd;
     "CMAKE_DISABLE_PRECOMPILE_HEADERS" = true;
-    "NO_UWSM" = true;
+    "NO_UWSM" = !withSystemd;
     "NO_HYPRPM" = true;
     "TRACY_ENABLE" = false;
   };