ashb opened a new pull request, #25995: URL: https://github.com/apache/airflow/pull/25995
This one was a fun one to track down, and was only a problem when the scheduler "expanded" the first mapped task (making it SKIPPED). - The scheduler looks at `add_one` and marks it as SKIPPED. - `unfinished_tis` contains add_one_1, and `_are_premature_tis` changes the state of `add_one__1`, (which just so happens to be a leaf task), and the check on line 584 essentially gets confused, as no one envisaged the states changing! In a reverse of how this normally plays out, if the mini_scheduler in the LocalTaskJob was disabled then this example DAG would deadlock every time. (Since that mini scheduler only operates on a partial DAG it can't ever change the whole DagRun state.) Fixes #25200 Ephraim had the idea of the fix, I just optomized it to not check the (possibly) large list everytime but only when a state was changed. <!-- Thank you for contributing! Please make sure that your code changes are covered with tests. And in case of new features or big changes remember to adjust the documentation. Feel free to ping committers for the review! In case of an existing issue, reference it using one of the following: closes: #ISSUE related: #ISSUE How to write a good git commit message: http://chris.beams.io/posts/git-commit/ --> --- **^ Add meaningful description above** Read the **[Pull Request Guidelines](https://github.com/apache/airflow/blob/main/CONTRIBUTING.rst#pull-request-guidelines)** for more information. In case of fundamental code changes, an Airflow Improvement Proposal ([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvement+Proposals)) is needed. In case of a new dependency, check compliance with the [ASF 3rd Party License Policy](https://www.apache.org/legal/resolved.html#category-x). In case of backwards incompatible changes please leave a note in a newsfragment file, named `{pr_number}.significant.rst` or `{issue_number}.significant.rst`, in [newsfragments](https://github.com/apache/airflow/tree/main/newsfragments). -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
