raycarter opened a new issue, #40620:
URL: https://github.com/apache/airflow/issues/40620

   ### Apache Airflow version
   
   2.9.2
   
   ### If "Other Airflow 2 version" selected, which one?
   
   _No response_
   
   ### What happened?
   
   We need to use BranchPythonOperator and dynamic task mapping in a DAG to 
meet our requirements. The BranchPythonOperator controls whether dynamic 
mapping is needed, and there is a task (branch_2_task) following the dynamic 
task mapping that must be executed regardless of whether the dynamic task 
mapping runs (it can be skipped by receiving an empty list). As shown in the 
diagram 1, the trigger_rule for branch_2_task needs to be set to none_failed. 
   
   diagram 1:
   
![image](https://github.com/apache/airflow/assets/2765326/5d12e4d8-365a-40ef-b554-09a5729fecbc)
   
   If it is set to all_success, the task branch_2_task will also be skipped if 
the dynamic mapping is skipped due to an empty list (diagram 2). 
   
   diagram 2:
   
![image](https://github.com/apache/airflow/assets/2765326/f063a815-2976-44d8-8006-fa80ebaae687)
   
   However, when BranchPythonOperator triggers the branch_1 task, the task 
branch_2_task on the other branch also gets executed (diagram 3). 
   
   diagram 3:
   
![image](https://github.com/apache/airflow/assets/2765326/31a2c2e6-112f-42c5-b8d0-4911bed161f7)
   
   The potential bug could be that Airflow does not check if a task is on the 
executing branch but only checks the trigger_rule.
   
   Could you fix this?
   
   ### What you think should happen instead?
   
   The task branch_2_task has trigger_rule none_failed to be executed even if 
the dynamic task mapping before it is skipped. If the other branch is executed, 
the task branch_2_task must be skipped because the branch should be skipped.
   
   ### How to reproduce
   
   - Airflow 2.9.2
   - the demo DAG is here: 
https://gist.github.com/raycarter/75e896d600adec0563545fc58e3795d2
     - use parameters condition1 = 2, mapping_count = 0 to reproduce diagram 1
     - use parameters condition1 = 1, mapping_count = 0 to reproduce diagram 3
     - change trigger_rule of branch_2_task to all_success, use parameters 
condition1 = 2, mapping_count = 0 to reproduce diagram 2 
   
   ### Operating System
   
   Ubuntu
   
   ### Versions of Apache Airflow Providers
   
   _No response_
   
   ### Deployment
   
   Other
   
   ### Deployment details
   
   _No response_
   
   ### Anything else?
   
   _No response_
   
   ### Are you willing to submit PR?
   
   - [ ] Yes I am willing to submit a PR!
   
   ### Code of Conduct
   
   - [X] I agree to follow this project's [Code of 
Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)
   


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