DagBundle Import Error Detected but Not Displayed in UI

[carlos54]

Apache Airflow version

Other Airflow 2/3 version (please specify below)

If "Other Airflow 2/3 version" selected, which one?

3.1.4

What happened?

Description : The Dag Processor correctly identifies and logs an import error within a DAG file, but the corresponding error message and Stack Trace are not visible in the Airflow User Interface (no "import Errors" tab).

DAG File Processing Stats
Bundle File Path PID Current Duration # DAGs # Errors Last Duration Last Run At
-------- ---------------------------------- ----- ------------------ -------- ---------- --------------- -------------------
sandbox sandbox_dag005_dataset_producer.py 1 0 0.26s 2025-12-10T11:38:29
sandbox sandbox_dag_demo.py 0 1 0.21s 2025-12-10T11:38:29

Error in log dag processor log file are correctly catch :

{"timestamp":"2025-12-10T11:33:23.270722Z","level":"error","event":"AirflowException(\"Task Policy validation failed for 'DO_DATASET':\\n[DATASET OUTLETS] Dataset URI 'event_data01_dispo' in
 task 'DO_DATASET' must start with 'sandbox_'.\")","logger":"airflow.models.dagbag.DagBag","filename":"dagbag.py","lineno":556,"error_detail":[{"exc_type":"AirflowException","exc_value":"Tas
k Policy validation failed for 'DO_DATASET':\n[DATASET OUTLETS] Dataset URI 'event_data01_dispo' in task 'DO_DATASET' must start with 'sandbox_'.","exc_notes":[],"syntax_error":null,"is_caus
e":false,"frames":[{"filename":"/usr/local/lib/python3.12/site-packages/airflow/models/dagbag.py","lineno":552,"name":"bag_dag"},{"filename":"/usr/local/lib/python3.12/site-packages/airflow/settings.py","lineno":183,"name":"task_policy"},{"filename":"/usr/local/lib/python3.12/site-packages/pluggy/_hooks.py","lineno":512,"name":"__call__"},{"filename":"/usr/local/lib/python3.12/site-packages/pluggy/_manager.py","lineno":120,"name":"_hookexec"},{"filename":"/usr/local/lib/python3.12/site-packages/pluggy/_callers.py","lineno":167,"name":"_multicall"},{"filename":"/usr/local/lib/python3.12/site-packages/pluggy/_callers.py","lineno":121,"name":"_multicall"},{"filename":"/opt/airflow/config/cluster_policy.py","lineno":173,"name":"task_policy"}],"is_group":false,"exceptions":[]}]}

This prevents developers from quickly identifying the source of the failure, especially those caused by the cluster_policy.

What you think should happen instead?

The "Import Errors" view in the Airflow UI should be display .

How to reproduce

The dag_processor ariflow.cfg: dag_bundle_config_list: '{{ .Values.DAGS.bundle_list }}' dag_bundle_storage_path: '/dags/airflow/bundles' refresh_interval: 60 bundle_refresh_check_interval : 15 print_stats_interval: 60 parsing_processes: 2 dag_file_processor_timeout: 60 min_file_process_interval: 30 stale_dag_threshold : 300

Operating System

redhat/ubi9:9.6

Versions of Apache Airflow Providers

apache-airflow==3.1.4
structlog==25.5.0
psycopg2-binary==2.9.11
asyncpg==0.31.0
apache-airflow-providers-fab==3.0.3
apache-airflow-providers-redis==4.4.0
apache-airflow-providers-git==0.1.0
apache-airflow-providers-cncf-kubernetes==10.11.0
flask-limiter==3.12
redis==5.3.1
authlib==1.6.5
PyJWT==2.10.1
cryptography==42.0.8
requests==2.32.5

Deployment

Official Apache Airflow Helm Chart

Deployment details

No response

Anything else?

No response

Are you willing to submit PR?

• [x] Yes I am willing to submit a PR!

Code of Conduct

• [x] I agree to follow this project's Code of Conduct