added ruff code reivew

examples/gui/viewer3d/camera_discovery.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import contextlib
+import logging
 import os
 import sys
 from dataclasses import dataclass
@@ -11,6 +12,8 @@ import cv2
 
 DEFAULT_MAX_CAMERA_INDEX = 10
 
+logger = logging.getLogger(__name__)
+
 
 @dataclass(frozen=True)
 class CameraInfo:
@@ -62,8 +65,14 @@ def _suppress_opencv_noise():
         if set_level is not None and prev_level is not None:
             try:
                 set_level(prev_level)
-            except Exception:
-                pass
+            except Exception as exc:
+                # Best-effort: a failure only leaves OpenCV probe noise suppressed,
+                # but report it so a stuck log level is diagnosable.
+                logger.warning(
+                    "camera discovery: could not restore OpenCV log level %r: %s",
+                    prev_level,
+                    exc,
+                )
 
 
 def _backend_candidates() -> list[tuple[str, int]]:
@@ -115,9 +124,21 @@ def list_cameras(max_index: int = DEFAULT_MAX_CAMERA_INDEX) -> list[CameraInfo]:
     backends = _backend_candidates()
 
     with _suppress_opencv_noise():
-        for index in range(0, max_index + 1):
+        for index in range(max_index + 1):
             for backend_name, backend_api in backends:
-                info = _try_open(index, backend_name, backend_api)
+                try:
+                    info = _try_open(index, backend_name, backend_api)
+                except Exception as exc:
+                    # Same hazard as the SDK enumerator: an escaping error for one
+                    # backend would abort the whole probe and hide every other
+                    # camera. Skip that candidate and keep going.
+                    logger.warning(
+                        "camera discovery: probing index %d via %s failed: %s",
+                        index,
+                        backend_name,
+                        exc,
+                    )
+                    continue
                 if info is None:
                     continue
                 if index in seen_indices: