Hello Simon, That issue looks very similar indeed. I will keep an eye on that ticket.
Thanks for your reply. Jose El domingo, 9 de abril de 2017, 1:58:55 (UTC+1), Simon Charette escribió: > > Hello Jose, > > I wouldn't be surprised if this was caused by a Django bug with prefetches > doing > weird things when the same model is referenced through different > relations[0]. > > Simon > > [0] https://code.djangoproject.com/ticket/26318 > > Le samedi 4 mars 2017 13:36:20 UTC-5, Jose Kilo a écrit : >> >> Hi all, >> >> I'm trying to use an annotated queryset inside a Prefetch object. For >> some reason I'm not getting the expected result. >> This is a simplified version of my models and query. >> >> >> class User(models.Model): >> >> following = models.ManyToManyField('User', related_name='followers', >> through='Follow') >> >> >> class Follow(models.Model): >> >> following = models.ForeignKey(User, on_delete=models.CASCADE, >> related_name='_followed') >> followed = models.ForeignKey(User, on_delete=models.CASCADE, >> related_name='_following') >> >> >> def test(): >> >> User.objects.all().delete() >> >> user_1 = User.objects.create() >> user_2 = User.objects.create() >> >> Follow.objects.create(following=user_1, followed=user_2) >> >> queryset = ( >> User.objects.all() >> .prefetch_related( >> Prefetch( >> 'followers', to_attr='prefetched_annotated_followers', >> queryset=(User.objects.all().annotate( >> followers_count=Count('followers', distinct=True), >> )) >> ), >> Prefetch( >> 'followers', to_attr='prefetched_followers', >> queryset=User.objects.all() >> ), >> ) >> ) >> >> user = queryset.last() >> print(list(user.followers.all())) # [<User: User object>] >> print(user.prefetched_followers) # [<User: User object>] >> print(user.prefetched_annotated_followers) # [] >> >> return queryset >> >> >> Why the last result is empty ? >> >> Just in case, I added 'prefetched_followers' to compare both results. If >> I remove it, 'prefetched_annotated_followers' still doesn't get anything. >> > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/b1f8a006-2de0-45da-b51f-6775da2d0de5%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
