[GitHub] [airflow] turbaszek edited a comment on pull request #10349: infer multiple_output from return type annotation

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turbaszek edited a comment on pull request #10349:
URL: https://github.com/apache/airflow/pull/10349#issuecomment-674477268


   Thanks @AndersonReyes for taking interest in this issue! This looks good but we need to adjust this logic of XCom storage:
   https://github.com/apache/airflow/blob/382c1011b6bcebd22760e2f98419281ef1a09d1b/airflow/operators/python.py#L243-L254
   
   Also the crucial part of this change is allowing users to reference those returned values before executing a task. For example this should work:
   ```python
   @task
   def task1() -> Tuple[str, int]:
       return "magic", 42
   
   
   @task 
   def task2(a: str, b: int) -> None:
       pass
   
   
   a, b = task1()
   task2(a, b)
   ```
   
   And this means that we have to implement some smart `__iter__` for `XComArg` class because that's the return type of `task1()` invocation.  Otherwise we get this:
   ```
       a, b = task2()
   ValueError: too many values to unpack (expected 2)
   ```
   
   
   


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