Improve VM options overrides

flake.lock

@@ -95,11 +95,11 @@
     },
     "impermanence": {
       "locked": {
-        "lastModified": 1644541943,
-        "narHash": "sha256-bMiRtPs3xh8S3duX7JiWLZdUZi7RwktpXGhykCdCroE=",
+        "lastModified": 1644585928,
+        "narHash": "sha256-jOnLRLnzFI/YHE53bHgz/9QjR4Qt6dgIXLnTZOf5oLc=",
         "owner": "devplayer0",
         "repo": "impermanence",
-        "rev": "4bfa7f8b6844be7172264c1f7c11ac0c89027f79",
+        "rev": "47809005570ee4d5b504e382309f5b6dcc5999e5",
         "type": "github"
       },
       "original": {
@@ -177,11 +177,11 @@
     },
     "nixpkgs-stable": {
       "locked": {
-        "lastModified": 1644193793,
-        "narHash": "sha256-ggCI5LCXwkUJQwjpkr9qDFbQMiK3JvAfeNR4Uy0ny5Q=",
+        "lastModified": 1644472683,
+        "narHash": "sha256-sP6iM4NksOYO6NFfTJ96cg+ClPnq6cdY30xKA1iYtyU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "521e4d7d13b09bc0a21976b9d19abd197d4e3b1e",
+        "rev": "7adc9c14ec74b27358a8df9b973087e351425a79",
         "type": "github"
       },
       "original": {

modules/tmproot.nix

@@ -1,7 +1,7 @@
 { lib, pkgs, inputs, config, ... }@args:
   let
     inherit (lib) any concatStringsSep mkIf mkDefault mkMerge mkVMOverride;
-    inherit (lib.my) mkOpt mkBoolOpt mkVMOverride';
+    inherit (lib.my) mkOpt mkBoolOpt mkVMOverride' dummyOption;
 
     cfg = config.my.tmproot;
 
@@ -63,6 +63,11 @@
       ];
     };
 
+    # Forward declare options that won't exist until the VM module is actually imported
+    options.virtualisation = {
+      diskImage = dummyOption;
+    };
+
     config = mkMerge [
       (mkIf cfg.enable {
         assertions = [
@@ -88,8 +93,7 @@
 
         fileSystems."/" = rootDef;
 
-        # If we need to override any VM-specific options that the modules system won't know about this early
-        my.asDevVM.config.virtualisation = {
+        virtualisation = {
           diskImage = "./.vms/${config.system.name}-persist.qcow2";
         };
       })

util.nix

@@ -13,4 +13,5 @@
       example = true;
     };
     mkVMOverride' = mkOverride 9;
+    dummyOption = mkOption {};
   }