vars: improve messaging

nixosModules/clanCore/vars/interface.nix

@@ -228,7 +228,7 @@ in
                       description = ''
                         Whether the file should be deployed to the target machine.
 
-                        Enable this if the generated file is only used as an input to other generators.
+                        Disable this if the generated file is only used as an input to other generators.
                       '';
                       type = bool;
                       default = true;

nixosModules/clanCore/vars/public/in_repo.nix

@@ -30,7 +30,9 @@ in
           readFile file.config.path
         else
           # if the file is not found, we want to downgrade the priority, to allow overriding via mkDefault
-          mkOptionDefault (throw "File not found: ${file.config.path}")
+          mkOptionDefault (
+            throw "Please run `clan vars generate ${config.clan.core.settings.machine.name}` as file was not found: ${file.config.path}"
+          )
       );
     };
   };