fix: expand seed \n escapes in process_file_updates

expand seed escapes in process_file_updates like echo -e

Signed-off-by: Elena German <elgerman@redhat.com>

Author: elenagerman

scripts/python/tasks/internal/process_file_updates.py

@@ -46,6 +46,8 @@
 PROG = "process_file_updates.py"
 FILE_UPDATES_SECRET_MOUNT_ENV = "FILE_UPDATES_SECRET_MOUNT"
 _REPLACEMENT_EXPRESSION = re.compile(r"^\|([^|\n]*)\|([^|\n]*)\|$")
+_SEED_ESCAPE = re.compile(r"\\([ntr\\])")
+_SEED_ESCAPE_REPLACEMENTS = {"n": "\n", "t": "\t", "r": "\r", "\\": "\\"}
 
 
 def _usage_text() -> str:
@@ -364,6 +366,14 @@ def resolve_target_file(repo_cwd: Path, entry_path: str) -> Path:
     return target_file
 
 
+def _expand_seed_content(seed: str) -> str:
+    """Expand backslash escapes in seed text like bash ``echo -e``."""
+    return _SEED_ESCAPE.sub(
+        lambda match: _SEED_ESCAPE_REPLACEMENTS[match.group(1)],
+        seed,
+    )
+
+
 def seed_target_file(entry: dict[str, Any], target_file: Path, repo_cwd: Path) -> None:
     """Create or overwrite *target_file* when the path entry includes a seed value."""
     seed = entry.get("seed") or ""
@@ -374,6 +384,7 @@ def seed_target_file(entry: dict[str, Any], target_file: Path, repo_cwd: Path) -
         return
     logger.info("seed operation to perform")
     target_file.parent.mkdir(parents=True, exist_ok=True)
+    seed = _expand_seed_content(seed)
     target_file.write_text(
         seed + ("\n" if not seed.endswith("\n") else ""),
         encoding="utf-8",

scripts/python/tasks/internal/test_process_file_updates.py

@@ -5,7 +5,8 @@
 
 - ``replacements``: ``test_run_file_updates_creates_mr``,
   ``test_apply_replacements_for_entry_applies_replacement``
-- ``seed``: ``test_seed_target_file_writes_and_stages``
+- ``seed``: ``test_seed_target_file_writes_and_stages``,
+  ``test_seed_target_file_expands_echo_e_escapes``
 - ``combo``: Tekton only (integration smoke)
 - ``replacements-idempotent``: ``test_run_file_updates_returns_existing_mr``,
   ``test_find_existing_mr_with_same_diff``
@@ -767,6 +768,72 @@ def test_seed_target_file_writes_and_stages(tmp_path: Path) -> None:
     status.assert_called_once_with(repo)
 
 
+def test_seed_target_file_expands_echo_e_escapes(tmp_path: Path) -> None:
+    """E2E-style seeds with literal ``\\n`` expand like bash ``echo -e``."""
+    repo = tmp_path / "repo"
+    repo.mkdir()
+    target = repo / "addons" / "my-addon.yaml"
+    paths_json = json.dumps(
+        [
+            {
+                "path": "addons/my-addon.yaml",
+                "seed": "indexImage: \\nname: my-addon\\nrelatedImages: []",
+            }
+        ]
+    )
+    seed = json.loads(paths_json)[0]["seed"]
+    with (
+        mock.patch.object(process_file_updates.vcs_git, "index_add_commit"),
+        mock.patch.object(
+            process_file_updates.vcs_git,
+            "working_tree_status",
+            return_value="",
+        ),
+    ):
+        process_file_updates.seed_target_file(
+            {"path": "addons/my-addon.yaml", "seed": seed},
+            target,
+            repo,
+        )
+    assert target.read_text(encoding="utf-8") == (
+        "indexImage: \nname: my-addon\nrelatedImages: []\n"
+    )
+
+
+def test_expand_seed_content_preserves_unicode() -> None:
+    """Non-ASCII seed text is not corrupted by escape expansion."""
+    seed = "label: café\\nemoji: 🚀\\tend"
+    assert process_file_updates._expand_seed_content(seed) == "label: café\nemoji: 🚀\tend"
+
+
+def test_expand_seed_content_leaves_unknown_escapes_and_trailing_backslash() -> None:
+    """Unrecognized escapes and trailing backslashes are left unchanged."""
+    assert process_file_updates._expand_seed_content(r"path\x\z") == r"path\x\z"
+    assert process_file_updates._expand_seed_content("trailing\\") == "trailing\\"
+    assert process_file_updates._expand_seed_content(r"keep\\slash") == r"keep\slash"
+
+
+def test_seed_target_file_preserves_unicode_content(tmp_path: Path) -> None:
+    """Seeded files retain arbitrary Unicode after escape expansion."""
+    repo = tmp_path / "repo"
+    repo.mkdir()
+    target = repo / "i18n.yaml"
+    with (
+        mock.patch.object(process_file_updates.vcs_git, "index_add_commit"),
+        mock.patch.object(
+            process_file_updates.vcs_git,
+            "working_tree_status",
+            return_value="",
+        ),
+    ):
+        process_file_updates.seed_target_file(
+            {"path": "i18n.yaml", "seed": "title: café\\nicon: 🚀"},
+            target,
+            repo,
+        )
+    assert target.read_text(encoding="utf-8") == "title: café\nicon: 🚀\n"
+
+
 def test_seed_target_file_propagates_git_add_failure(tmp_path: Path) -> None:
     """``seed-error`` Tekton: git add failure propagates (``main`` maps to Failed)."""
     repo = tmp_path / "repo"