refactor review-plan safety and validation

src/vlm/scanner.py

@@ -155,6 +155,29 @@ def _discover_video_paths(root: Path, video_extensions: list[str]) -> list[Path]
         return _discover_video_paths_recursive(root, video_extensions)
 
 
+def _log_find_nonzero_exit(returncode: int, stderr_text: str, discovered_count: int) -> None:
+    """Log the explicit contract for non-zero `find` exits.
+
+    Contract: if `find` emits partial stdout before failing, keep those paths and
+    continue with a warning. If no paths were emitted, return an empty result and
+    log that scan discovery was incomplete.
+    """
+    stderr_suffix = f": {stderr_text}" if stderr_text else ""
+    if discovered_count > 0:
+        logger.warning(
+            "find exited with code %s; using %s partial scan result(s)%s",
+            returncode,
+            discovered_count,
+            stderr_suffix,
+        )
+    else:
+        logger.warning(
+            "find exited with code %s and produced no scan results%s",
+            returncode,
+            stderr_suffix,
+        )
+
+
 def _discover_video_paths_with_find(root: Path, video_extensions: list[str]) -> list[Path]:
     """Discover matching video files using the system `find` command."""
     normalized_extensions = [ext.lower() for ext in video_extensions if ext]
@@ -175,11 +198,6 @@ def _discover_video_paths_with_find(root: Path, video_extensions: list[str]) ->
     )
     stdout, stderr = process.communicate()
 
-    if process.returncode != 0:
-        stderr_text = stderr.decode(errors="replace").strip()
-        if stderr_text:
-            logger.warning(f"find reported issues while scanning: {stderr_text}")
-
     discovered_paths: list[Path] = []
     for path_bytes in stdout.split(b"\0"):
         if not path_bytes:
@@ -189,6 +207,10 @@ def _discover_video_paths_with_find(root: Path, video_extensions: list[str]) ->
             continue
         discovered_paths.append(file_path)
 
+    if process.returncode != 0:
+        stderr_text = stderr.decode(errors="replace").strip()
+        _log_find_nonzero_exit(process.returncode, stderr_text, len(discovered_paths))
+
     return discovered_paths