Celery: Results returned from group have task_name=None

[keisetsu]

When I try to access the taskname from a result that has come from group, None is returned

Python(s): 3.3.6, 3.4.2
celery: 3.1.17

proj/celery.py

from celery import Celery

app = Celery('proj',
             broker='amqp://',
             backend='amqp://',
             include=['proj.tasks'])

# Optional configuration, see the application user guide.
app.conf.update(
    CELERY_TASK_RESULT_EXPIRES=3600,
)

if __name__ == '__main__':
    app.start()

proj/tasks.py

from proj.celery import app

@app.task
def add(x, y):
    return x + y


@app.task
def mul(x, y):
    return x * y

run_add.py

from celery import group

from proj import tasks

import logging

log = logging.getLogger(__name__)
logging.basicConfig(level=logging.DEBUG)

results = group([
    tasks.mul.s(4,4),
    tasks.add.s(3,3)
]).delay()

while results.waiting():
    pass

if results.successful():
    for result in results:
        log.info('ID: {}, name: {}'.format(result.task_id, result.task_name))

Result:

INFO:__main__:ID: c2fa4f30-0691-41ee-8f7b-e7dcbf32d09a, name: None
INFO:__main__:ID: f545bfa0-2ad7-40b3-9d05-561d4c1eba7e, name: None

[kstratis]

Same thing seems to also be happening with chains too.
There's also a stackoverflow post about it:

Get the task_name from AsyncResult when submitting chains in celery

[ask]

task_name is a local field, it's not used for anything anymore and I guess it should be removed completely.

The result sent does not actually have a name field, it was used at some point to serialize the backend with the result when using pickle, but that is accomplished differently now.

[joshma]

@ask is there no way to grab the task_name now? We have an endpoint used to expose task data to the web, and we'd like to, given an AsyncResult, log the name of the task.