Label in front of TaskGroup breaks task dependencies

[cb149]

Apache Airflow version: 2.1.0

What happened:

Using a Label infront of a TaskGroup breaks task dependencies, as tasks before the TaskGroup will now point to the last task in the TaskGroup.

What you expected to happen:

Task dependencies with or without Labels should be the same (and preferably the Label should be visible outside of the TaskGroup).
Behavior without a Label is as follows:

with TaskGroup("tg1", tooltip="Tasks related to task group") as tg1:
        DummyOperator(task_id="b") >> DummyOperator(task_id="c")

DummyOperator(task_id="a") >> tg1

How to reproduce it:

with TaskGroup("tg1", tooltip="Tasks related to task group") as tg1:
        DummyOperator(task_id="b") >> DummyOperator(task_id="c")

    DummyOperator(task_id="a") >> Label("testlabel") >> tg1

[boring-cyborg]

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[bbovenzi]

I was able to replicate. It seems to be an issue with selecting the wrong target_id for a label. It should pick the first one in a group but instead it picks the last one.

See here

[kaxil]

@bbovenzi Do we have a fix for this?