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Pass the scheduler's session to set_state when processing executor events #73810

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Pass the scheduler's session to set_state when processing executor events #73810

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5a6622f
Pass the scheduler's session to set_state when processing executor ev…
namanjain24-sudo Sep 15, 2026
cf2bac6
Key the executor-events transaction test by TaskInstanceUuid
namanjain24-sudo Oct 5, 2026
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2 changes: 1 addition & 1 deletion airflow-core/src/airflow/jobs/scheduler_job_runner.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1663,7 +1663,7 @@ def process_executor_events(
task = dag.get_task(ti.task_id)
except Exception:
cls.logger().exception("Marking task instance %s as %s", ti, state)
ti.set_state(state)
ti.set_state(state, session=session)
continue
ti.task = task
if task.has_on_retry_callback or task.has_on_failure_callback:
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35 changes: 35 additions & 0 deletions airflow-core/tests/unit/jobs/test_scheduler_job.py
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Original file line number Diff line number Diff line change
Expand Up @@ -825,6 +825,41 @@ def test_executor_event_diagnostic_distinguishes_locked_row_from_nonprocessable_
else:
scalars.assert_not_called()

def test_process_executor_events_sets_state_in_callers_transaction(self, dag_maker):
"""
Setting a task instance's state must not commit the caller's transaction.

``settings.Session`` is scoped, so ``ti.set_state()`` without ``session`` resolved to the
scheduler's own session and ``create_session()`` committed and closed it on exit. That released
the scheduler's row locks mid-batch and detached the task instances still to be processed, so
changes made to them afterwards were never written.

This covers the Dag-not-found path: the Dag can't be loaded, so the task instance is marked
with the executor's reported state directly, without a session it would otherwise resolve to
the scheduler's own scoped session and commit early.
"""
session = settings.Session()
with dag_maker(dag_id="test_executor_events_callers_transaction", fileloc="/test_path1/"):
task1 = EmptyOperator(task_id="test_task", retries=2)
ti1 = dag_maker.create_dagrun().get_task_instance(task1.task_id)
ti1.state = TaskInstanceState.QUEUED
session.merge(ti1)
session.commit()

executor = MockExecutor(do_update=False)
job_runner = SchedulerJobRunner(Job(), executors=[executor])
job_runner.scheduler_dag_bag = mock.MagicMock()
job_runner.scheduler_dag_bag.get_dag_for_run.side_effect = Exception("failed")
executor.event_buffer[TaskInstanceUuid(ti1.id)] = State.FAILED, None

job_runner._process_executor_events(executor=executor, session=session)
ti1.refresh_from_db(session=session)
assert ti1.state == TaskInstanceState.FAILED
session.rollback()

ti1.refresh_from_db(session=session)
assert ti1.state == TaskInstanceState.QUEUED

@mock.patch("airflow.jobs.scheduler_job_runner.TaskCallbackRequest")
@mock.patch("airflow._shared.observability.metrics.stats._get_backend")
def test_process_executor_events_with_no_callback(self, mock_get_backend, mock_task_callback, dag_maker):
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