nixos-rebuild-ng: add FLAKE_FLAGS to nix copy (#419594)

pkgs/by-name/ni/nixos-rebuild-ng/package.nix

@@ -15,6 +15,13 @@
   # Very long tmp dirs lead to "too long for Unix domain socket"
   # SSH ControlPath errors. Especially macOS sets long TMPDIR paths.
   withTmpdir ? if stdenv.hostPlatform.isDarwin then "/tmp" else null,
+  # This version is kind of arbitrary, we use some features that were
+  # implemented in newer versions of Nix, but not necessary 2.18.
+  # However, Lix is a fork of Nix 2.18, so this looks like a good version
+  # to cut specific functionality.
+  # ATTN: This currently doesn't disambiguate between Nix and Lix, so using this
+  # in a conditional needs careful checking against both Nix implementations.
+  withNix218 ? lib.versionAtLeast nix.version "2.18",
   # passthru.tests
   nixosTests,
   nixVersions,
@@ -23,13 +30,6 @@
 }:
 let
   executable = if withNgSuffix then "nixos-rebuild-ng" else "nixos-rebuild";
-  # This version is kind of arbitrary, we use some features that were
-  # implemented in newer versions of Nix, but not necessary 2.18.
-  # However, Lix is a fork of Nix 2.18, so this looks like a good version
-  # to cut specific functionality.
-  # ATTN: This currently doesn't disambiguate between Nix and Lix, so using this
-  # in a conditional needs careful checking against both Nix implementations.
-  withNix218 = lib.versionAtLeast nix.version "2.18";
 in
 python3Packages.buildPythonApplication rec {
   pname = "nixos-rebuild-ng";

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

@@ -210,6 +210,7 @@ def copy_closure(
         run_wrapper(
             [
                 "nix",
+                *FLAKE_FLAGS,
                 "copy",
                 *dict_to_flags(copy_flags),
                 "--from",

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

@@ -688,6 +688,8 @@ def test_execute_nix_switch_build_target_host(
             call(
                 [
                     "nix",
+                    "--extra-experimental-features",
+                    "nix-command flakes",
                     "copy",
                     "--from",
                     "ssh://user@build-host",

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

@@ -263,6 +263,8 @@ def test_copy_closure(monkeypatch: MonkeyPatch) -> None:
         mock_run.assert_called_with(
             [
                 "nix",
+                "--extra-experimental-features",
+                "nix-command flakes",
                 "copy",
                 "--copy-flag",
                 "--from",