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.

Asked By: Denise Mauldin

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Source

Answers:

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.

Answered By: Denise Mauldin

I was getting this warning when i used objects.all() in my view.py

profile_list = Profile.objects.all()
paginator = Paginator(profile_list, 25)

to fix this i changed my code to :

profile_list = Profile.objects.get_queryset().order_by('id')
paginator = Paginator(profile_list, 25)
Answered By: Rajiv Sharma

Another option is to add OrderingFilter

http://www.django-rest-framework.org/api-guide/filtering/#orderingfilter

Answered By: Michael Benin

Let me give an answer updated to new developments…

https://code.djangoproject.com/ticket/6089

The default ordering of the User model has been removed in Django. If you found yourself at this page because of an upgrade, it’s very likely connected to this change.

There are 2 versions of this problem you might be dealing with.

  1. your own model does not have a default ordering in its Meta (see accepted answer)
  2. you are using a model from an app you are using as a dependency which does not have a default ordering

Since literally the Django User model itself does not adhere to ordering, it’s very clear that the second scenario cannot be resolved by asking the maintainers of those dependencies to put in a default ordering. Okay, so now you either have to override the model being used for whatever your doing (sometimes a good idea, but not good for addressing such a minor issue).

So you’re left with addressing it on the view level. You also want to do something that will play nicely with any ordering filter class you have applied. For that, set the view’s ordering parameter.

class Reviewers(ListView):
    model = User
    paginate_by = 50
    ordering = ['username']

Also see Is there Django List View model sort?

Answered By: AlanSE

Including this didn’t work for me.

class Meta:
   ordering = ['-id']

But changing get_queryset(self) and sorting the list with .order_by(‘id’) did. Maybe worked because I’m using filters, I don’t know

class MyView(viewsets.ModelViewSet):
    queryset = MyModel.objects.all()
    serializer_class = MySerializerSerializer

    def get_queryset(self):
        user = self.request.user
        return MyModel.objects.filter(owner=user).order_by('id')
Answered By: Malinoski

Update the model meta class instead.

class UsefulModel(models.Model):
    
    class Meta:
        ordering='-created' # for example

you can still override the ordering from the view attribute ‘ordering’ As advised by AlanSE previously.

class UsefulView(ListView):
    ordering = ['-created']
Answered By: Ahmed Shehab

In my case, I had to add order_by('id') instead of ordering.

class IntakeCaseViewSet(viewsets.ModelViewSet):
    schema = None
    queryset = IntakeCase.objects.all().order_by('id')

Ordering needs to be in the model using Class Meta (not View).

Answered By: Paul Schreiber

In my case, it expected a tuple and that tuple has to contain a comma even when you are parsing just an item in it.

     class Meta:
      ordering = ('-name',)
Answered By: SanRaph