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https://issues.apache.org/jira/browse/AIRFLOW-6170?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Bjorn Olsen updated AIRFLOW-6170:
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Issue Type: Bug (was: Improvement)
> BranchPythonOperator does not do XCom push of returned value
> ------------------------------------------------------------
>
> Key: AIRFLOW-6170
> URL: https://issues.apache.org/jira/browse/AIRFLOW-6170
> Project: Apache Airflow
> Issue Type: Bug
> Components: operators
> Affects Versions: 1.10.6
> Reporter: Bjorn Olsen
> Assignee: Bjorn Olsen
> Priority: Minor
>
> BranchPythonOperator subclasses PythonOperator and this means that after it
> has selected a branch we get a message like this:
> [2019-12-04 08:39:59,960] \{python_operator.py:114} INFO - Done. Returned
> value was: chosen_task
>
> This returned value is from the execute() method. A user would expect the
> returned value from this to be pushed to an XCOM but this does not happen due
> to no return value from the BranchPythonOperator's execute method.
>
>
> {code:java}
> def execute(self, context: Dict):
> branch = super().execute(context)
> self.skip_all_except(context['ti'], branch)
> {code}
>
> If we do an XCOM push of the result then we can use the decision made by
> BranchPythonOperator in downstream tasks.
> Eg consider this dependency chain:
> get >> branch >> [ create, update ]>> join >> execute
> The 'execute' task might need to know whether the 'branch' decided to create
> a new thing to run, or whether to use the existing one from the 'get'.
> Without an XCOM push from the branch return value, it is difficult to pick up
> the correct value later on.
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