AttributeError attempting to flush m2m cache

[sirdodger]

I am running a Django 2.2.11 (but I also tested with 2.2.15) installation with django-waffle 1.0.0, and I am getting a failure in the m2m signal. As far as I can tell from the docs, that should be allowed?

File "/usr/local/lib/python3.5/dist-packages/waffle/signals.py", line 11, in flag_membership_changed
    instance.flush()
AttributeError: 'User' object has no attribute 'flush'

I can replicate it with a clean installation.

[k4rl85]

I bumped on the same issue.
After some digging i found a problem in the signal receiver flag_membership_changed.

This issue is caused by how m2m_changed retrieve the instance. The code except to receive always an instance of model Flag but this is not guarantee from m2m_changed signal.

More info here
https://docs.djangoproject.com/en/dev/ref/signals/#m2m-changed