Fix DAG-level on_failure_callback not firing

airflow-core/src/airflow/callbacks/callback_requests.py

@@ -22,9 +22,8 @@
 import structlog
 from pydantic import BaseModel, Field, model_validator
 from sqlalchemy import inspect as sa_inspect
-from sqlalchemy.exc import NoInspectionAvailable
+from sqlalchemy.exc import NoInspectionAvailable, SQLAlchemyError
 from sqlalchemy.orm.attributes import set_committed_value
-from sqlalchemy.orm.exc import DetachedInstanceError
 
 from airflow.api_fastapi.execution_api.datamodels import taskinstance as ti_datamodel  # noqa: TC001
 from airflow.utils.state import TaskInstanceState
@@ -116,19 +115,20 @@ def _sanitize_consumed_asset_events(cls, values: Mapping[str, Any]) -> Mapping[s
         except NoInspectionAvailable:
             return values
 
-        # Relationship access may raise DetachedInstanceError; on that path, reload DagRun
-        # from the DB to avoid crashing the scheduler.
+        # Relationship access may raise DetachedInstanceError or other SQLAlchemy
+        # exceptions (e.g. InvalidRequestError when the session is closed); on that
+        # path, reload the DagRun from the DB to avoid crashing the scheduler.
         try:
             events = dag_run.consumed_asset_events
             set_committed_value(
                 dag_run,
                 "consumed_asset_events",
                 list(events) if events is not None else [],
             )
-        except DetachedInstanceError:
+        except SQLAlchemyError:
             log.warning(
-                "DagRunContext encountered DetachedInstanceError while accessing "
-                "consumed_asset_events; reloading DagRun from DB."
+                "DagRunContext failed to access consumed_asset_events; reloading DagRun from DB.",
+                exc_info=True,
             )
             from sqlalchemy import select
             from sqlalchemy.orm import selectinload
@@ -137,8 +137,8 @@ def _sanitize_consumed_asset_events(cls, values: Mapping[str, Any]) -> Mapping[s
             from airflow.models.dagrun import DagRun
             from airflow.utils.session import create_session
 
-            # Defensive guardrail: reload DagRun with eager-loaded relationships on
-            # DetachedInstanceError to recover state without adding DB I/O to the hot path.
+            # Reload DagRun with eager-loaded relationships to recover state
+            # without adding DB I/O to the hot path.
             with create_session() as session:
                 dag_run_reloaded = session.scalar(
                     select(DagRun)

airflow-core/src/airflow/jobs/scheduler_job_runner.py

@@ -2439,6 +2439,12 @@ def _send_dag_callbacks_to_processor(
         callback: DagCallbackRequest | None = None,
     ) -> None:
         if callback:
+            self.log.debug(
+                "Sending %s callback request for dag_id=%s, run_id=%s to DAG Processor",
+                "failure" if callback.is_failure_callback else "success",
+                callback.dag_id,
+                callback.run_id,
+            )
             self.executor.send_callback(callback)
         else:
             self.log.debug("callback is empty")