nixos-rebuild-ng: fix printing

print user info (diffs) into stderr, add back missing newline

pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py

@@ -540,7 +540,7 @@ def list_generations(profile: Profile) -> list[GenerationJson]:
 
 def diff_closures(current_config: Path, new_config: Path, target_host: Remote | None = None):
     print(
-        f"<<< {current_config}"
+        f"<<< {current_config}\n"
         f">>> {new_config}",
         file=sys.stderr
     )
@@ -554,6 +554,7 @@ def diff_closures(current_config: Path, new_config: Path, target_host: Remote |
             new_config,
         ],
         remote=target_host,
+        stdout=sys.stderr
     )
 
 

pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py

@@ -1,3 +1,4 @@
+import sys
 import textwrap
 import uuid
 from pathlib import Path
@@ -568,7 +569,8 @@ def test_diff_closures(mock_run: Mock) -> None:
             Path("/run/current-system"),
             Path("/nix/var/nix/profiles/system"),
         ],
-        remote=None
+        remote=None,
+        stdout=sys.stderr
     )