[Answered ]-How does Celery handle task failures within a chain?

I believe the following snippet is the closest thing to describing this.

“When you call retry it will send a new message, using the same task-id, and it will take care to make sure the message is delivered to the same queue as the originating task.

When a task is retried this is also recorded as a task state, so that you can track the progress of the task using the result instance (see States).”

I believe where it state that the task state is tracked best describes what you are looking for.

I also know this based on first hand experience