potiuk commented on issue #26200:
URL: https://github.com/apache/airflow/issues/26200#issuecomment-1250260900

   Hmmm I think everything is as expected. 
   
   1) when you manually set task on 10.00  to "skipped" - it will be skipped 
without taking "depends_on_past" into account. "Depends_on_past" only prevents 
the tasks from RUNNING when the same task in previous instance is not 
"succeeded" or "skipped". But when you manually force it to "skip" this is not 
done. If you would like it to "wait" for previous task to run, you would have 
to have a new state "waiting for skipping" or smth. I.e. you would like to have 
a state when we know that the task should be skipped immediately when it is 
eligible to run. Airfow has no such state and it's quite doubtful if it will 
ever have one
   
   2) Then the task at 11.00 will only look at the "last previous", not "all 
previous" tasks and it will see tha the previous task is skipped, so it will 
run immediately.
   
   All is fine, as expected and perfectly reflects the current state of Airflow 
implementation, so this is not a bug.
   
   What you likely would like to get instead is a new feature for example 
"depend_on_all_past_not_runnning" or similar, where you should check if there 
is ANY past task that is currently not "completed" and "queued" or "running". 
But I think this one is not needed. It is quite a bit more complex to 
implemented, I think and  it might be a bit more "predictable" in terms of 
execution sequence, but probably much better, simpler and something that you 
can implement even now, is to assign a separate pool for your task with size = 
1. This will make sure that only one task instance can run at a time. This is 
PROBABLY what you really want to achieve. There is no guarantee on sequence of 
execution - so if you run 5 of those instances one after the other then, they 
will execute in a "random" sequence, but In most cases of scheduled run, they 
should run in a proper sequence as past task will be already running while the 
future task is scheduled.
   
   Converting to a discussion.
   
   
   


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