fix(api): return cleanly on lock contention in clean_dataset_queries_task

Re-raise LockError after printing a skip message caused false task
failures for normal lock contention. Return instead to exit cleanly.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

api/schedule/clean_dataset_queries_task.py

@@ -88,14 +88,17 @@ def clean_dataset_queries_task() -> None:
 
     except LockError:
         end_at = time.perf_counter()
-        logger.exception("clean_dataset_queries_task: acquire task lock failed, skip current execution")
+        logger.warning(
+            "clean_dataset_queries_task: lock already held, skip current execution"
+        )
         click.echo(
             click.style(
-                f"clean_dataset_queries_task: skipped (lock already held), latency: {end_at - start_at:.2f}s",
+                f"clean_dataset_queries_task: skipped (lock already held), "
+                f"latency: {end_at - start_at:.2f}s",
                 fg="yellow",
             )
         )
-        raise
+        return
     except Exception:
         end_at = time.perf_counter()
         logger.exception("clean_dataset_queries_task failed")

api/tests/unit_tests/schedule/test_clean_dataset_queries_task.py

@@ -58,8 +58,8 @@ class TestCleanDatasetQueriesTask:
     @patch("schedule.clean_dataset_queries_task.db")
     @patch("schedule.clean_dataset_queries_task.dify_config")
     def test_lock_held_skips(self, mock_cfg, mock_db, mock_redis):
-        """When the Redis lock is already held, the task raises LockError and
+        """When the Redis lock is already held, the task exits cleanly without
-        makes no database calls."""
+        database calls or raising an error."""
         mock_cfg.CLEAN_DATASET_QUERIES_RETENTION_DAYS = 60
         mock_cfg.PLAN_SANDBOX_CLEAN_DAY_SETTING = 30
 
@@ -71,8 +71,7 @@ class TestCleanDatasetQueriesTask:
         session = MagicMock()
         mock_db.session = session
 
-        with pytest.raises(LockError):
+        clean_dataset_queries_task()
-            clean_dataset_queries_task()
 
         session.scalars.assert_not_called()
         session.execute.assert_not_called()