`ALL_DONE` trigger rule not respected in TaskFlow API for upstream failures

Apache Airflow version

2.3.0

What happened

Hello!

I’m using taskflow api for my dag and was trying to run the last task even if the previous task failed, I used @task(trigger_rule=TriggerRule.ALL_DONE) but i still got the ending task failed too.

The UI confirms that I declared the trigger_rule “all_done”

What you think should happen instead

No response

How to reproduce

This is the whole code

import logging
import pendulum
from airflow.decorators import task, dag
from airflow.utils.trigger_rule import TriggerRule


@dag(
    schedule_interval=None,
    start_date=pendulum.datetime(2021, 5, 10, tz="UTC"),
    catchup=False,
)
def taskflow_trigger():
    @task()
    def first_task():
        return "first_task"

    @task
    def second_task(value):
        return "second_task"

    @task
    def task_to_fail(value):
        data = {"test": 1}
        val = data["not_here"]
        return val

    @task(trigger_rule=TriggerRule.ALL_DONE)
    def end(value):

        return "yes"

    op_1 = first_task()
    op_3 = task_to_fail(op_1)
    op_2 = second_task(op_1)
    end([op_3, op_2])

taskflow_trigger = taskflow_trigger()

Operating System

"Debian GNU/Linux 11 (bullseye)

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

• I agree to follow this project’s Code of Conduct

[uranusjr]

Since an XCom push can never be None[^1], we can probably just set the value to None in this case. Combining this with #24401, we probably need to do some additional checks in XComArg.resolve() to take account the current task’s trigger rule, and resolve to None when appropriate.

[^1]: A design decision I didn’t agree with but that ship sailed long ago.

[ashb]

Duplicate of #24338 (It’s the same underlying cause)