KevinYang21 opened a new issue #8989:
URL: https://github.com/apache/airflow/issues/8989


   **Description**
   In `airflow backfill`, `-I` is available so that the task instance of the 
first DAG run will ignore depends_on_past setting. It is a bit confusing from 
its name that it is a concept only for backfill jobs. For scheduled jobs, this 
behavior is on by default. However, one case we've been seeing a lot is that 
when new tasks with `depends_on_past=True` was added, it will not be scheduled 
until its previous TI is marked as success. This is because when we are 
checking the taks deps, we consider a task instance the first task instance 
only when it's from the first DAG run of the DAG(roughly), 
[code](https://github.com/apache/airflow/blob/master/airflow/ti_deps/deps/prev_dagrun_dep.py#L46-L65).
   
   Proposed new behavior: 
   
   **Use case / motivation**
   So that after adding new task, people don't need to remember manually 
marking the previous TI as success before getting the new task running.
   
   <!-- What do you want to happen?
   Add a new property `ignore_first_depends_on_past` in BaseOperator and 
control its value through a config entry. If it is true, then first task 
instance of a task will not respect `depends_on_past` setting. A task instance 
will be considered as the first task instance of a task when there is not task 
instance in the DB with an execution_date earlier than it.
   
   Or, making it the default behavior.
   
   -->
   
   **Related Issues**
   No
   


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