impermanence: link home profile during system activation

services/impermanence.nix

@@ -64,4 +64,19 @@ in
       ];
     users = listToAttrs (map persistUser config.machine.administrators);
   };
+
+  # link current home manager profile if it exists
+  # impermanence mounts come after system activation during boot
+  # we check the persistent location and link to the expected mount point
+  system.activationScripts.profile-init.text = concatStrings (
+    map (
+      user:
+      with user; # bash
+      ''
+        if [[ -d /persist/home/${name}/.local/state/nix/profiles/profile ]]; then
+          ln -sfn /home/${name}/.local/state/nix/profiles/profile /home/${name}/.nix-profile
+        fi
+      ''
+    ) config.machine.administrators
+  );
 }