Python Django Rest Framework UnorderedObjectListWarning

Question

I upgraded from Django 1.10.4 to 1.11.1 and all of a sudden I'm getting a ton of these messages when I run my tests:

lib/python3.5/site-packages/rest_framework/pagination.py:208:
UnorderedObjectListWarning: 
Pagination may yield inconsistent results with an unordered object_list: 
<QuerySet [<Group: Requester>]>
paginator = self.django_paginator_class(queryset, page_size)

I've traced that back to the Django Pagination module: https://github.com/django/django/blob/master/django/core/paginator.py#L100

It seems to be related to my queryset code:

return get_user_model().objects.filter(id=self.request.user.id)

How can I find more details on this warning? It seems to be that I need to add a order_by(id) on the end of every filter, but I can't seem to find which code needs the order_by added (because the warning doesn't return a stack trace and so it happens randomly during my test run).

Thanks!

Edit:

So by using @KlausD. verbosity tip, I looked at a test causing this error:

response = self.client.get('/api/orders/')

This goes to OrderViewSet but none of the things in get_queryset cause it and nothing in serializer class causes it. I have other tests that use the same code to get /api/orders and those don't cause it.... What does DRF do after get_queryset?

https://github.com/encode/django-rest-framework/blob/master/rest_framework/pagination.py#L166

If I put a traceback into pagination then I get a whole bunch of stuff related to django rest framework but nothing that points back to which of my queries is triggering the order warning.

Answer 1

So in order to fix this I had to find all of the all, offset, filter, and limit clauses and add a order_by clause to them. Some I fixed by adding a default ordering:

class Meta:
   ordering = ['-id']

In the ViewSets for Django Rest Framework (app/apiviews.py) I had to update all of the get_queryset methods as adding a default ordering didn't seem to work.

Hope this helps someone else. :)