Commit c58755d8 authored by Brian King's avatar Brian King Committed by Tim Graham
Browse files

[1.8.x] Fixed #24912 -- Fixed prefetch_related failure for UUIDField primary keys 

This resolves a problem on databases besides PostgreSQL when using
prefetch_related with a source model that uses a UUID primary key.

Backport of bfb5b715 from master
parent 062ce508

django/db/models/fields/related.py

+4 −1
Original line number Diff line number Diff line
@@ -954,7 +954,10 @@ def create_many_related_manager(superclass, rel): 
                    getattr(result, '_prefetch_related_val_%s' % f.attname)

                    for f in fk.local_related_fields

                ),

                lambda inst: tuple(getattr(inst, f.attname) for f in fk.foreign_related_fields),

                lambda inst: tuple(

                    f.get_db_prep_value(getattr(inst, f.attname), connection)

                    for f in fk.foreign_related_fields

                ),

                False,

                self.prefetch_cache_name,

            )

docs/releases/1.8.3.txt

+3 −0
Original line number Diff line number Diff line
@@ -66,3 +66,6 @@ Bugfixes 
* Provided better backwards compatibility for the ``verbosity`` argument in

  ``optparse`` management commands by casting it to an integer

  (:ticket:`24769`).



* Fixed ``prefetch_related()`` on databases other than PostgreSQL for models

  using UUID primary keys (:ticket:`24912`).

tests/prefetch_related/models.py

+17 −0
Original line number Diff line number Diff line 
import uuid



from django.contrib.contenttypes.fields import (

    GenericForeignKey, GenericRelation,

)
@@ -257,3 +259,18 @@ class Author2(models.Model): 


    class Meta:

        ordering = ['id']





# Models for many-to-many with UUID pk test:



class Pet(models.Model):

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)

    name = models.CharField(max_length=20)

    people = models.ManyToManyField(Person, related_name='pets')





class Flea(models.Model):

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)

    current_room = models.ForeignKey(Room, related_name='fleas', null=True)

    pets_visited = models.ManyToManyField(Pet, related_name='fleas_hosted')

    people_visited = models.ManyToManyField(Person, related_name='fleas_hosted')

tests/prefetch_related/test_uuid.py

0 → 100644
+95 −0
Original line number Diff line number Diff line 
from __future__ import unicode_literals



from django.test import TestCase



from .models import Flea, House, Person, Pet, Room





class UUIDPrefetchRelated(TestCase):



    def test_prefetch_related_from_uuid_model(self):

        Pet.objects.create(name='Fifi').people.add(

            Person.objects.create(name='Ellen'),

            Person.objects.create(name='George'),

        )



        with self.assertNumQueries(2):

            pet = Pet.objects.prefetch_related('people').get(name='Fifi')

        with self.assertNumQueries(0):

            self.assertEqual(2, len(pet.people.all()))



    def test_prefetch_related_to_uuid_model(self):

        Person.objects.create(name='Bella').pets.add(

            Pet.objects.create(name='Socks'),

            Pet.objects.create(name='Coffee'),

        )



        with self.assertNumQueries(2):

            person = Person.objects.prefetch_related('pets').get(name='Bella')

        with self.assertNumQueries(0):

            self.assertEqual(2, len(person.pets.all()))



    def test_prefetch_related_from_uuid_model_to_uuid_model(self):

        fleas = [Flea.objects.create() for i in range(3)]

        Pet.objects.create(name='Fifi').fleas_hosted.add(*fleas)

        Pet.objects.create(name='Bobo').fleas_hosted.add(*fleas)



        with self.assertNumQueries(2):

            pet = Pet.objects.prefetch_related('fleas_hosted').get(name='Fifi')

        with self.assertNumQueries(0):

            self.assertEqual(3, len(pet.fleas_hosted.all()))



        with self.assertNumQueries(2):

            flea = Flea.objects.prefetch_related('pets_visited').get(pk=fleas[0].pk)

        with self.assertNumQueries(0):

            self.assertEqual(2, len(flea.pets_visited.all()))





class UUIDPrefetchRelatedLookups(TestCase):



    @classmethod

    def setUpTestData(cls):

        house = House.objects.create(name='Redwood', address='Arcata')

        room = Room.objects.create(name='Racoon', house=house)

        fleas = [Flea.objects.create(current_room=room) for i in range(3)]

        pet = Pet.objects.create(name='Spooky')

        pet.fleas_hosted.add(*fleas)

        person = Person.objects.create(name='Bob')

        person.houses.add(house)

        person.pets.add(pet)

        person.fleas_hosted.add(*fleas)



    def test_from_uuid_pk_lookup_uuid_pk_integer_pk(self):

        # From uuid-pk model, prefetch <uuid-pk model>.<integer-pk model>:

        with self.assertNumQueries(4):

            spooky = Pet.objects.prefetch_related('fleas_hosted__current_room__house').get(name='Spooky')

        with self.assertNumQueries(0):

            self.assertEqual('Racoon', spooky.fleas_hosted.all()[0].current_room.name)



    def test_from_uuid_pk_lookup_integer_pk2_uuid_pk2(self):

        # From uuid-pk model, prefetch <integer-pk model>.<integer-pk model>.<uuid-pk model>.<uuid-pk model>:

        with self.assertNumQueries(5):

            spooky = Pet.objects.prefetch_related('people__houses__rooms__fleas').get(name='Spooky')

        with self.assertNumQueries(0):

            self.assertEqual(3, len(spooky.people.all()[0].houses.all()[0].rooms.all()[0].fleas.all()))



    def test_from_integer_pk_lookup_uuid_pk_integer_pk(self):

        # From integer-pk model, prefetch <uuid-pk model>.<integer-pk model>:

        with self.assertNumQueries(3):

            racoon = Room.objects.prefetch_related('fleas__people_visited').get(name='Racoon')

        with self.assertNumQueries(0):

            self.assertEqual('Bob', racoon.fleas.all()[0].people_visited.all()[0].name)



    def test_from_integer_pk_lookup_integer_pk_uuid_pk(self):

        # From integer-pk model, prefetch <integer-pk model>.<uuid-pk model>:

        with self.assertNumQueries(3):

            redwood = House.objects.prefetch_related('rooms__fleas').get(name='Redwood')

        with self.assertNumQueries(0):

            self.assertEqual(3, len(redwood.rooms.all()[0].fleas.all()))



    def test_from_integer_pk_lookup_integer_pk_uuid_pk_uuid_pk(self):

        # From integer-pk model, prefetch <integer-pk model>.<uuid-pk model>.<uuid-pk model>:

        with self.assertNumQueries(4):

            redwood = House.objects.prefetch_related('rooms__fleas__pets_visited').get(name='Redwood')

        with self.assertNumQueries(0):

            self.assertEqual('Spooky', redwood.rooms.all()[0].fleas.all()[0].pets_visited.all()[0].name)