return_value is None despite the data is saved in the db

[k4ml]

I'm just following the README's example.

from myapp.tasks import calculate_meaning_of_life
>>> res = calculate_meaning_of_life.enqueue()
>>> res.return_value
Traceback (most recent call last):
  File "/usr/lib/python3.10/code.py", line 90, in runcode
    exec(code, self.locals)
  File "<console>", line 1, in <module>
  File "/home/kamal/git/django-tasks/django_tasks/task.py", line 268, in return_value
    raise ValueError("Task has not finished yet")
ValueError: Task has not finished yet
>>> res.refresh()
>>> res.return_value is None
True
>>> from django_tasks.backends.database.models import DBTaskResult
>>> db_result = DBTaskResult.objects.get(id=res.id)
>>> db_result.return_value
42

I have run just tests and it all passed.

[k4ml]

If we look at tests/tests/test_database_backend.py in test_refresh_result, we can see there's no assert on return_value and if we inspect it, the value is None.

[RealOrangeOne]

This sounds like a very strange bug to me, which I can reproduce. I'll give it a look.

[RealOrangeOne]

Looks like this was wider scope than I thought. The return value was never exposed correctly when using the database backend at all!

This is now fixed with 22d51b3.

[k4ml]

Great! It is fixed now.

>>> from myapp.tasks import calculate_meaning_of_life
>>> res = calculate_meaning_of_life.enqueue()
>>> res.return_value
Traceback (most recent call last):
  File "/usr/lib/python3.10/code.py", line 90, in runcode
    exec(code, self.locals)
  File "<console>", line 1, in <module>
  File "/home/kamal/git/django-tasks/django_tasks/task.py", line 268, in return_value
    raise ValueError("Task has not finished yet")
ValueError: Task has not finished yet
>>> res.refresh()
>>> res.return_value
42