'NoneType' object has no attribute 'refresh_from_task' Error when manually running task instance #19477

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1. potiuk

   added

   kind:bugThis is a clearly a bugThis is a clearly a bug

   area:core

   on Nov 8, 2021
2. potiuk commented on Nov 8, 2021

   

   potiuk

   on Nov 8, 2021

   MemberAuthor

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   Copied from discussion:
   here is some code examples:

   from datetime import datetime
   
   from airflow.operators.python_operator import PythonOperator
   from airflow import DAG
   
   with DAG('a_dag',  schedule_interval=None, default_args={'start_date': datetime(2018, 1, 1, 0, 0, 0)}) as dag:
       def success(*args, **kwargs):
           print('ok')
   
       some_task = PythonOperator(task_id='some_tasks', python_callable=success)
   

   and with new task

   from datetime import datetime
   
   from airflow.operators.python_operator import PythonOperator
   from airflow import DAG
   
   with DAG('a_dag',  schedule_interval=None, default_args={'start_date': datetime(2018, 1, 1, 0, 0, 0)}) as dag:
       def success(*args, **kwargs):
           print('ok')
   
       some_task = PythonOperator(task_id='some_tasks', python_callable=success)
       new_task = PythonOperator(task_id='new_task', python_callable=success)
   and steps to reproduce:
   

   1. Define "a_dag" with "some_tasks".
   2. Create dag run (manually or by schedule)
   3. Add "new_task" into dag, deploy code
   4. Select "new_task" in UI and press "Run" button
3. potiuk commented on Nov 8, 2021

   

   potiuk

   on Nov 8, 2021

   MemberAuthor

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   cc: @a-pertsev
4. potiuk

   added a commit that references this issue on Nov 8, 2021

   Do not crash with stacktrace when task instance is missing

   ...

   This issue will close once commit cb77afe is merged into the 'main' branch.

   cb77afe
5. potiuk

   closed this as completedin #19478on Nov 8, 2021
6. potiuk

   added a commit that references this issue on Nov 8, 2021

   Do not crash with stacktrace when task instance is missing (#19478)

   ...

   This issue will close once commit 51d61a9 is merged into the 'main' branch.

   51d61a9
7. a-pertsev commented on Nov 11, 2021

   

   a-pertsev

   on Nov 11, 2021

   Last edited by a-pertsev

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   @potiuk as i can see in #19478, attempt of running newly created task will cause redirect with error message.
   In previous versions airflow was creating and running new task instance - imho it is more preferable behaviour, beacause it is what user expects airflow to do
8. potiuk commented on Nov 11, 2021

   

   potiuk

   on Nov 11, 2021

   Last edited by potiuk

   MemberAuthor

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   I am afraid it is not possible now because of how DAG serializatiion works (and I think this is correct behaviour to be honest). But you can raise a feature request for that (with justification etc.)