Revert "fix: build closure in build-step instead of on iso"

This reverts commit b23525df78.

installer/artifacts.nix

@@ -20,12 +20,6 @@ let
       targetConfig = self.nixosConfigurations.${hostName}.config;
       targetSystemBuild = targetConfig.system.build;
       diskoScript = targetConfig.system.build.diskoScript;
-      
-      # Build the closure export at build time (not runtime in ISO)
-      closureExport = pkgs.runCommand "closure-export-${hostName}" { } ''
-        mkdir -p $out
-        ${pkgs.nix}/bin/nix-store --export $(${pkgs.nix}/bin/nix-store -qR ${targetSystem}) > $out/closure.nar
-      '';
     in
     nixpkgs.lib.nixosSystem {
       inherit system;
@@ -35,7 +29,6 @@ let
           hostName
           targetSystemBuild
           diskoScript
-          closureExport
           ;
         hostPlatform = system;
       };

installer/auto-install.nix

@@ -1,7 +1,6 @@
 # This module defines a systemd service that automatically installs NixOS to the disk.
 # It is intended to be used in an installation ISO.
-# It expects `targetSystem` (the closure to install), `diskoScript` (the partitioning script),
-# and `closureExport` (the pre-built NAR archive) to be passed as arguments.
+# It expects `targetSystem` (the closure to install) and `diskoScript` (the partitioning script) to be passed as arguments.
 {
   config,
   lib,
@@ -11,7 +10,6 @@
   hostPlatform,
   targetSystemBuild,
   diskoScript,
-  closureExport,
   ...
 }:
 {
@@ -23,12 +21,8 @@
     targetSystemBuild.toplevel
   ];
 
-  # Explicitly include the pre-built closure export and system in the ISO image
+  # Explicitly include the system closure in the ISO image to prevent any need to build or fetch
   isoImage.contents = [
-    {
-      source = closureExport;
-      target = "/closure-export";
-    }
     {
       source = targetSystem;
       target = "/system";
@@ -65,12 +59,27 @@
       echo ">>> Running disko script..."
       ${diskoScript}
 
+<<<<<<< HEAD
       echo ">>> Setting up NixOS..."
       nixos-install \
       --system ${targetSystemBuild.toplevel} \
       --no-root-passwd \
       --no-channel-copy \
       --substituters "" 
+=======
+      echo ">>> Copying system closure to target..."
+      # Copy the entire system closure without substitution
+      nix-store --store /mnt --load-db < <(nix-store --dump-db)
+      nix-copy-closure --to /mnt ${targetSystem} 2>/dev/null || true
+
+      echo ">>> Running nixos-install..."
+      # Install with pre-built closure already in store
+      nixos-install \
+        --no-root-passwd \
+        --root /mnt \
+        --system ${targetSystem} \
+        --option substitute false
+>>>>>>> parent of b23525d (fix: build closure in build-step instead of on iso)
 
       echo ">>> Done. Rebooting."
       systemctl reboot