qt: use home.sessionSearchVariables

modules/misc/qt.nix

@@ -170,13 +170,10 @@ in {
       inherit (config.home) profileDirectory;
       qtVersions = with pkgs; [ qt5 qt6 ];
       makeQtPath = prefix:
-        lib.concatStringsSep ":"
         (map (qt: "${profileDirectory}/${qt.qtbase.${prefix}}") qtVersions);
     in {
-      QT_PLUGIN_PATH = "$QT_PLUGIN_PATH\${QT_PLUGIN_PATH:+:}"
-        + (makeQtPath "qtPluginPrefix");
-      QML2_IMPORT_PATH = "$QML2_IMPORT_PATH\${QML2_IMPORT_PATH:+:}"
-        + (makeQtPath "qtQmlPrefix");
+      QT_PLUGIN_PATH = makeQtPath "qtPluginPrefix";
+      QML2_IMPORT_PATH = makeQtPath "qtQmlPrefix";
     };
 
   in lib.mkIf cfg.enable {
@@ -194,19 +191,14 @@ in {
 
     home = {
       sessionVariables = envVars;
-      # home.sessionVariables does not support setting the same environment
-      # variable to different values.
-      # Since some other modules may set the QT_PLUGIN_PATH or QML2_IMPORT_PATH
-      # to their own value, e.g.: fcitx5, we avoid conflicts by setting
-      # the values in home.sessionVariablesExtra instead.
-      sessionVariablesExtra = ''
-        export QT_PLUGIN_PATH=${envVarsExtra.QT_PLUGIN_PATH}
-        export QML2_IMPORT_PATH=${envVarsExtra.QML2_IMPORT_PATH}
-      '';
+      sessionSearchVariables = envVarsExtra;
     };
 
     # Apply theming also to apps started by systemd.
-    systemd.user.sessionVariables = envVars // envVarsExtra;
+    systemd.user.sessionVariables = envVars // {
+      QT_PLUGIN_PATH = lib.concatStringsSep ":" envVarsExtra.QT_PLUGIN_PATH;
+      QML2_IMPORT_PATH = lib.concatStringsSep ":" envVarsExtra.QML2_IMPORT_PATH;
+    };
 
     home.packages = (lib.optionals (cfg.platformTheme != null)
       platformPackages.${cfg.platformTheme} or [ ])

tests/modules/misc/qt/qt-platform-theme-gtk.nix

@@ -6,7 +6,6 @@
       enable = true;
       platformTheme = "gtk";
     };
-    i18n.inputMethod.enabled = "fcitx5";
 
     nmt.script = ''
       assertFileRegex home-path/etc/profile.d/hm-session-vars.sh \