grayver opened a new issue #11347: URL: https://github.com/apache/airflow/issues/11347
**Apache Airflow version**: 1.10.12 **Environment**: - **Cloud provider or hardware configuration**: Amazon EC2 instance, 4 CPU cores, 8GB RAM - **OS** (e.g. from /etc/os-release): Ubuntu 18.04.5 LTS (Bionic Beaver) - **Kernel** (e.g. `uname -a`): Linux ip-XX-XX-XX-XX.ec2.internal 5.4.0-1025-aws #25~18.04.1-Ubuntu SMP Fri Sep 11 12:03:04 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux - **Install tools**: Ansible Airflow role (https://github.com/idealista/airflow-role) **What happened**: I've made a combination of example DAGs from Airflow documentation (Branching section and Trigger Rules section): <details><summary>branching_dag.py</summary> ```python from airflow.models import DAG from airflow.operators.dummy_operator import DummyOperator from airflow.operators.bash_operator import BashOperator from airflow.operators.python_operator import BranchPythonOperator from airflow.utils.dates import days_ago from airflow.utils.trigger_rule import TriggerRule dag = DAG( dag_id='branching_dag', schedule_interval=None, start_date=days_ago(1) ) run_this_first = DummyOperator(task_id='run_this_first', dag=dag) branching = BranchPythonOperator( task_id='branching', dag=dag, python_callable=lambda: 'branch_a' ) branch_a = DummyOperator(task_id='branch_a', dag=dag) follow_branch_a = BashOperator(task_id='follow_branch_a', dag=dag, bash_command='sleep 30s') branch_b = DummyOperator(task_id='branch_b', dag=dag) join = DummyOperator(task_id='join', dag=dag, trigger_rule=TriggerRule.NONE_FAILED_OR_SKIPPED) run_this_first >> branching branching >> branch_a >> follow_branch_a >> join branching >> join branching >> branch_b >> join ``` </details> Here is original image from Branching section of documentation:  and here is image from Trigger Rules section:  According to DAG graph whichever branch would be selected, `join` task should be executed anyway. But I'm getting this:  So, `join` task is skipped right after `branch_a` is selected. **What you expected to happen**: According to documentation (Branching section): > Paths of the branching task are branch_a, join and branch_b. Since join is a downstream task of branch_a, it will be excluded from the skipped tasks when branch_a is returned by the Python callable. and from Trigger rules section: > The join task will be triggered as soon as branch_false has been skipped (a valid completion state) and follow_branch_a has succeeded. Because skipped tasks will not cascade through none_failed_or_skipped. But it's not fulfilled in practice. ---------------------------------------------------------------- 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: [email protected]
