update/flake-upload: set correct remote-program for macOS targets

pkgs/clan-cli/clan_lib/machines/update.py

@@ -52,12 +52,12 @@ def upload_sources(machine: Machine, ssh: Host, force_fetch_local: bool) -> str:
     remote_url_base = ssh.target
     remote_program_params = ""
     # MacOS doesn't come with a proper login shell for ssh and therefore doesn't have nix in $PATH as it doesn't source /etc/profile
-    if machine._class_ == "darwin":
-        remote_program_params = "?remote-program=bash -lc 'exec nix-daemon --stdio'"
 
     if not has_path_inputs and not force_fetch_local:
         # Just copy the flake to the remote machine, we can substitute other inputs there.
         path = flake_data["path"]
+        if machine._class_ == "darwin":
+            remote_program_params = "?remote-program=bash -lc 'exec nix-daemon --stdio'"
         remote_url = f"ssh-ng://{remote_url_base}{remote_program_params}"
         cmd = nix_command(
             [
@@ -83,6 +83,10 @@ def upload_sources(machine: Machine, ssh: Host, force_fetch_local: bool) -> str:
     # Don't use ssh-ng here. It makes `flake archive` fail, despite root@..., with:
     #   cannot add path '/nix/store/...' because it lacks a signature by a trusted key
     # The issue is the missing `--no-check-sigs` option in `nix flake archive`.
+    if machine._class_ == "darwin":
+        remote_program_params = (
+            "?remote-program=bash -lc 'exec nix-store --serve --write'"
+        )
     remote_url = f"ssh://{remote_url_base}{remote_program_params}"
     cmd = nix_command(
         [