nixos/plasma5: fix mismatch between nix and module system

In https://github.com/NixOS/nixpkgs/pull/254071, a mismatch between usage of
the Nix language and the NixOS module system was introduced. By merging the
kwin_wayland wrapper attrset into the mkIf representation, the former was
effectively ignored.
As a result, the capability wrapper for kwin_wayland stopped being installed,
leading to realtime scheduling being disabled. The issue was not detected
because the behavioral change is very subtle.

By consistently using language-level constructs, this mismatch is resolved.
The capability wrapper is thus installed again and realtime scheduling is
restored.

1 files changed, 2 insertions, 2 deletions

diff --git a/nixos/modules/services/x11/desktop-managers/plasma5.nix b/nixos/modules/services/x11/desktop-managers/plasma5.nix
index 282a34f6b01..7beac35d449 100644
--- a/nixos/modules/services/x11/desktop-managers/plasma5.nix
+++ b/nixos/modules/services/x11/desktop-managers/plasma5.nix
@@ -29,7 +29,7 @@ let
   libsForQt5 = pkgs.plasma5Packages;
   inherit (libsForQt5) kdeGear kdeFrameworks plasma5;
   inherit (lib)
-    getBin optionalString literalExpression
+    getBin optionalAttrs optionalString literalExpression
     mkRemovedOptionModule mkRenamedOptionModule
     mkDefault mkIf mkMerge mkOption mkPackageOptionMD types;
 
@@ -178,7 +178,7 @@ in
           capabilities = "cap_sys_nice+ep";
           source = "${getBin plasma5.kwin}/bin/kwin_wayland";
         };
-      } // mkIf (!cfg.runUsingSystemd) {
+      } // optionalAttrs (!cfg.runUsingSystemd) {
         start_kdeinit = {
           setuid = true;
           owner = "root";