nixos-rebuild-ng: error if --upgrade/--upgrade-all is called without --sudo/root

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

@@ -699,6 +699,12 @@ def upgrade_channels(all_channels: bool = False, sudo: bool = False) -> None:
     It will either upgrade just the `nixos` channel (including any channel
     that has a `.update-on-nixos-rebuild` file) or all.
     """
+    if not sudo and os.geteuid() != 0:
+        raise NixOSRebuildError(
+            "if you pass the '--upgrade' or '--upgrade-all' flag, you must "
+            "also pass '--sudo' or run the command as root (e.g., with sudo)"
+        )
+
     for channel_path in Path("/nix/var/nix/profiles/per-user/root/channels/").glob("*"):
         if channel_path.is_dir() and (
             all_channels

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

@@ -836,15 +836,28 @@ def test_switch_to_configuration_with_systemd_run(
     ],
 )
 @patch("pathlib.Path.is_dir", autospec=True, return_value=True)
-def test_upgrade_channels(mock_is_dir: Mock, mock_glob: Mock) -> None:
-    with patch(get_qualified_name(n.run_wrapper, n), autospec=True) as mock_run:
-        n.upgrade_channels(all_channels=False, sudo=True)
+@patch("os.geteuid", autospec=True, return_value=1000)
+@patch(get_qualified_name(n.run_wrapper, n), autospec=True)
+def test_upgrade_channels(
+    mock_run: Mock,
+    mock_geteuid: Mock,
+    mock_is_dir: Mock,
+    mock_glob: Mock,
+) -> None:
+    with pytest.raises(m.NixOSRebuildError) as e:
+        n.upgrade_channels(all_channels=False, sudo=False)
+    assert str(e.value) == (
+        "error: if you pass the '--upgrade' or '--upgrade-all' flag, you must "
+        "also pass '--sudo' or run the command as root (e.g., with sudo)"
+    )
+
+    n.upgrade_channels(all_channels=False, sudo=True)
     mock_run.assert_called_once_with(
         ["nix-channel", "--update", "nixos"], check=False, sudo=True
     )
 
-    with patch(get_qualified_name(n.run_wrapper, n), autospec=True) as mock_run:
-        n.upgrade_channels(all_channels=True, sudo=False)
+    mock_geteuid.return_value = 0
+    n.upgrade_channels(all_channels=True, sudo=False)
     mock_run.assert_has_calls(
         [
             call(["nix-channel", "--update", "nixos"], check=False, sudo=False),