OpenLineage listener causes DetachedInstanceError in system tests

[alamashir]

Description

Google Cloud system tests (BigQuery, and likely others) fail due to a DetachedInstanceError thrown by the OpenLineage listener in on_dag_run_failed / on_dag_run_success. All operator tasks complete successfully, but the watcher task marks the DAG run as failed because the OpenLineage listener errors out.

Reproduction

Run any Google Cloud BigQuery system test:

export SYSTEM_TESTS_GCP_PROJECT=<your-project>
export SYSTEM_TESTS_ENV_ID=test01
export PYTHONPATH=providers/google/tests:providers/openlineage/tests:$PYTHONPATH

uv run --project providers/google pytest --system \
  providers/google/tests/system/google/cloud/bigquery/example_bigquery_queries.py -xvs --with-db-init

Error

WARNING  airflow.providers.openlineage.plugins.listener:listener.py:971 OpenLineage received exception in method on_dag_run_failed
...
  File ".../openlineage/utils/utils.py", line 756, in <lambda>
    "note": lambda dagrun: getattr(dagrun, "note", None) if AIRFLOW_V_3_2_PLUS else None,
...
sqlalchemy.orm.exc.DetachedInstanceError: Parent instance <DagRun at 0x...> is not bound to a Session;
lazy load operation of attribute 'dag_run_note' cannot proceed

Root Cause

The DagRunInfo._cast_fields() method in providers/openlineage/src/airflow/providers/openlineage/utils/utils.py accesses dagrun.note, which triggers a lazy load of the dag_run_note association proxy on a DagRun instance that is no longer bound to a SQLAlchemy session.

This was likely introduced by #62347 ("feat: Add DagRun note to OL events").

Impact

All system tests with a watcher task fail, even though all actual operator tasks complete successfully. This blocks contributors from getting clean system test results.

Environment

• Airflow main branch (latest)
• Running locally via uv run (not breeze)
• SQLite backend