base: tag generation as auto if built by auto upgrade service

base/default.nix

@@ -46,6 +46,10 @@
 
   system.nixos.tags = lib.optionals (inputs.self.sourceInfo ? dirtyRev) [ "dirty" ];
 
+  specialisation."auto-upgrade".configuration = {
+    system.nixos.tags = [ "auto" ];
+  };
+
   boot.tmp.cleanOnBoot = lib.mkDefault true;
   boot.kernelPackages = lib.mkDefault pkgs.linuxPackages_latest;
 

base/services/auto-upgrade.nix

@@ -13,6 +13,7 @@ in
 
       "--refresh"
       "--no-write-lock-file"
+      "--specialisation auto-upgrade"
       # --update-input is deprecated since nix 2.22, and removed in lix 2.90
       # as such we instead use --override-input combined with --refresh
       # https://git.lix.systems/lix-project/lix/issues/400