Stop dag processor from warning on every file path normalized for stats (#71091)

* Stop dag processor from warning on every file path normalized for stats

* Apply suggestions from code review

Co-authored-by: Ephraim Anierobi <splendidzigy24@gmail.com>

---------

Co-authored-by: Ephraim Anierobi <splendidzigy24@gmail.com>

Author: bujjibabukatta

airflow-core/src/airflow/dag_processing/manager.py

@@ -155,7 +155,7 @@ def presence_key(self) -> tuple[str, Path]:
     @property
     def normalized_file_path_for_stats(self) -> str:
         """Return the relative file path normalized for use in stats tags."""
-        return normalize_name_for_stats(str(self.rel_path))
+        return normalize_name_for_stats(str(self.rel_path), log_warning=False)
 
 
 def _config_int_factory(section: str, key: str):

airflow-core/tests/unit/dag_processing/test_manager.py

@@ -3802,3 +3802,20 @@ def test_get_team_names_batches_and_caches(self, mock_get_team_names):
         # Two bundles resolved in a single batched query; the repeat call is served from cache.
         mock_get_team_names.assert_called_once()
         assert manager._bundle_name_to_team_name == {"bundle_a": "team_alpha", "bundle_b": "team_alpha"}
+
+
+def test_normalized_file_path_for_stats_does_not_warn(caplog):
+    """
+    rel_path always contains "/" for any nested DAG file, so normalizing it for stats
+    always requires substitution -- this must not log a warning on every DAG file, every
+    processing cycle.
+    """
+    dag_file_info = DagFileInfo(
+        bundle_name="testing", bundle_path=TEST_DAGS_FOLDER, rel_path=Path("dags/test/test_dag.py")
+    )
+
+    with caplog.at_level(logging.WARNING, logger="airflow._shared.observability.metrics.stats"):
+        result = dag_file_info.normalized_file_path_for_stats
+
+    assert result == "dags_test_test_dag.py"
+    assert caplog.entries == []