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ASF GitHub Bot commented on AIRFLOW-5391: ----------------------------------------- yuqian90 commented on pull request #8992: URL: https://github.com/apache/airflow/pull/8992#issuecomment-650531210 > @yuqian90 tests are failing, can you take a look please Hi @kaxil thank you. I looked into it. I think `tests/operators/test_latest_only_operator.py:test_run` is the only one related to my change. The reason `test_latest_only_operator.py:test_run` fails in this PR but not in master is that master has another commit https://github.com/apache/airflow/pull/5970. So I cherry-picked https://github.com/apache/airflow/pull/5970 into my PR as well. `test_latest_only_operator.py:test_run` should now pass. ``` XCom.set( key=XCOM_SKIPMIXIN_KEY, value={XCOM_SKIPMIXIN_SKIPPED: [d.task_id for d in tasks]}, task_id=task_id, > dag_id=dag_run.dag_id, execution_date=dag_run.execution_date, session=session ) E AttributeError: 'NoneType' object has no attribute 'dag_id' ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org > Clearing a task skipped by BranchPythonOperator will cause the task to execute > ------------------------------------------------------------------------------ > > Key: AIRFLOW-5391 > URL: https://issues.apache.org/jira/browse/AIRFLOW-5391 > Project: Apache Airflow > Issue Type: Bug > Components: operators > Affects Versions: 1.10.4 > Reporter: Qian Yu > Assignee: Qian Yu > Priority: Major > Fix For: 2.0.0 > > > I tried this on 1.10.3 and 1.10.4, both have this issue: > E.g. in this example from the doc, branch_a executed, branch_false was > skipped because of branching condition. However if someone Clear > branch_false, it'll cause branch_false to execute. > !https://airflow.apache.org/_images/branch_good.png! > This behaviour is understandable given how BranchPythonOperator is > implemented. BranchPythonOperator does not store its decision anywhere. It > skips its own downstream tasks in the branch at runtime. So there's currently > no way for branch_false to know it should be skipped without rerunning the > branching task. > This is obviously counter-intuitive from the user's perspective. In this > example, users would not expect branch_false to execute when they clear it > because the branching task should have skipped it. > There are a few ways to improve this: > Option 1): Make downstream tasks skipped by BranchPythonOperator not > clearable without also clearing the upstream BranchPythonOperator. In this > example, if someone clears branch_false without clearing branching, the Clear > action should just fail with an error telling the user he needs to clear the > branching task as well. > Option 2): Make BranchPythonOperator store the result of its skip condition > somewhere. Make downstream tasks check for this stored decision and skip > themselves if they should have been skipped by the condition. This probably > means the decision of BranchPythonOperator needs to be stored in the db. > > [kevcampb|https://blog.diffractive.io/author/kevcampb/] attempted a > workaround and on this blog. And he acknowledged his workaround is not > perfect and a better permanent fix is needed: > [https://blog.diffractive.io/2018/08/07/replacement-shortcircuitoperator-for-airflow/] > -- This message was sent by Atlassian Jira (v8.3.4#803005)