retsilla opened a new issue, #49714: URL: https://github.com/apache/airflow/issues/49714
### Apache Airflow version 3.0.0 ### If "Other Airflow 2 version" selected, which one? _No response_ ### What happened? When dynamically creating task groups and creating a task to consume combined results, the input received by the consuming task is `None` rather than a list of combined results. ### What you think should happen instead? According to the [example in docs](https://airflow.apache.org/docs/apache-airflow/stable/authoring-and-scheduling/dynamic-task-mapping.html#depending-on-a-mapped-task-group-s-output) and behaviour in previous versions of Airflow the result passed to the consuming tasks should be a combined list of results from the task group instances. ### How to reproduce DAG derived from the [example in the docs](https://airflow.apache.org/docs/apache-airflow/stable/authoring-and-scheduling/dynamic-task-mapping.html#depending-on-a-mapped-task-group-s-output): ```python from datetime import datetime from airflow.sdk import DAG, task, task_group with DAG( dag_id="dynamic_task_group_dag", start_date=datetime(2025, 1, 1), schedule=None, ): @task_group def add_one_and_double(value: int): @task def add_one(value: int): return value + 1 @task def double(value: int): return value * 2 new_value = add_one(value) return double(new_value) @task def consumer(values: list[int]): print(f"New values are: {values}") results = add_one_and_double.expand(value=[1, 2, 3]) consumer(results) # Should receive [4, 6, 8] but gets null ```  Logs of `consumer` task showing null was received: ``` [2025-04-24, 13:14:50] INFO - DAG bundles loaded: dags-folder: source="airflow.dag_processing.bundles.manager.DagBundlesManager" [2025-04-24, 13:14:50] INFO - Filling up the DagBag from /home/airflow/dags/dynamic_task_group_dag.py: source="airflow.models.dagbag.DagBag" [2025-04-24, 13:14:50] INFO - Done. Returned value was: None: source="airflow.task.operators.airflow.providers.standard.decorators.python._PythonDecoratedOperator" [2025-04-24, 13:14:50] INFO - New values are: None: chan="stdout": source="task" ``` ### Operating System Debian GNU/Linux 12 ### Versions of Apache Airflow Providers _No response_ ### Deployment Docker-Compose ### Deployment details _No response_ ### Anything else? _No response_ ### Are you willing to submit PR? - [ ] Yes I am willing to submit a PR! ### Code of Conduct - [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
