link_error in send_task not working as documented

[andreynovikov]

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Related Issues and Possible Duplicates

Related Issues

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Possible Duplicates

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Description

Error handler, as it is described in https://docs.celeryq.dev/en/stable/userguide/calling.html#linking-callbacks-errbacks does not work for the following code:

headers = {...}
link = signature(process_step_result, options={'headers': headers})
link_error = signature(process_step_error, options={'headers': headers})
app.send_task(step.action.task, link=link, link_error=link_error, headers=headers)

When I use error function signature as proposed in documentation I get:

TypeError: process_step_error() missing 2 required positional arguments: 'exc' and 'traceback'

When I switch to older variant:

@app.task
def process_step_error(task_id):
    result = app.AsyncResult(task_id)
    result.get(propagate=False)

I get Never call result.get() within a task error meaning that is is NOT called directly, as also stated in documentation.

When I add allow_join_result:

@app.task
def process_step_error(task_id):
    with allow_join_result():
        result = app.AsyncResult(task_id)
        result.get(propagate=False)

I can reach the result

I use:
Celery v5.4.0
Python 3.12
Redis as transport and results database

Suggestions

Either support for link_error in send_task should be documented separately or implementation fixed.