dheerajturaga commented on code in PR #73746:
URL: https://github.com/apache/airflow/pull/73746#discussion_r4210897199
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airflow-core/docs/core-concepts/dags.rst:
##########
@@ -624,6 +624,59 @@ If you want to see a more advanced use of TaskGroup, you
can look at the ``examp
When using the ``@task_group`` decorator, the decorated-function's
docstring will be used as the TaskGroups tooltip in the UI except when a
``tooltip`` value is explicitly supplied.
+.. _concepts:taskgroup-cycles:
+
+Cyclic TaskGroup dependencies
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. deprecated:: 3.4.0
+ Dags with cyclic TaskGroup dependencies are planned to fail Dag parsing
from Airflow 3.5.
+
+When each TaskGroup is treated as a single unit, a TaskGroup and its siblings
must not depend on each other
+in a cycle. A dependency into or out of any task in a group counts as a
dependency of the whole group. This
+can make a group both upstream and downstream of a sibling, although no
task-level dependency forms a cycle:
+
+.. code-block:: python
+
+ with TaskGroup("group1"):
+ a1 = EmptyOperator(task_id="a1")
+ a2 = EmptyOperator(task_id="a2")
+
+ with TaskGroup("group2"):
+ b1 = EmptyOperator(task_id="b1")
+ b2 = EmptyOperator(task_id="b2")
+
+ a1 >> b1 # group2 depends on group1
+ b2 >> a2 # group1 depends on group2
+
+A path that leaves a TaskGroup and comes back into it also forms a cycle, even
when the tasks inside the
Review Comment:
Agreed, it is intended. dags.rst now has it as its own example, says a
TaskGroup that holds a setup and its teardown must also hold the tasks between
them, and gives the fix (move `work` into `cluster`). The SDK tests pin both
sides: `setup-teardown-around-outside-task` warns with "cluster and work", and
`setup-teardown-in-group` does not warn.
---
Drafted-by: Claude Code (Opus 5.5); reviewed by @dheerajturaga before posting
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