Commit 161e26c2 authored by Anssi Kääriäinen's avatar Anssi Kääriäinen
Browse files

[1.6.x] Fixed #20955 -- select_related regression 

In cases where the same connection (from model A to model B along the
same field) was needed multiple times in a select_related query, the
join setup code mistakenly reused an existing join.

Backpatch of 8d65b608.

Conflicts:

	django/db/models/sql/compiler.py
	tests/queries/tests.py
parent 69a4594c

django/db/models/sql/compiler.py

+2 −3
Original line number Diff line number Diff line
@@ -687,8 +687,7 @@ class SQLCompiler(object): 
                # Use True here because we are looking at the _reverse_ side of

                # the relation, which is always nullable.

                new_nullable = True

                table = model._meta.db_table

                self.fill_related_selections(model._meta, table, cur_depth+1,

                self.fill_related_selections(model._meta, alias, cur_depth + 1,

                                             next, restricted, new_nullable)



    def deferred_to_columns(self):

tests/queries/models.py

+26 −0
Original line number Diff line number Diff line
@@ -497,3 +497,29 @@ class OrderItem(models.Model): 


    def __str__(self):

        return '%s' % self.pk



class BaseUser(models.Model):

    pass



@python_2_unicode_compatible

class Task(models.Model):

    title = models.CharField(max_length=10)

    owner = models.ForeignKey(BaseUser, related_name='owner')

    creator = models.ForeignKey(BaseUser, related_name='creator')



    def __str__(self):

        return self.title



@python_2_unicode_compatible

class Staff(models.Model):

    name = models.CharField(max_length=10)



    def __str__(self):

        return self.name



@python_2_unicode_compatible

class StaffUser(BaseUser):

    staff = models.OneToOneField(Staff, related_name='user')



    def __str__(self):

        return self.staff

tests/queries/tests.py

+21 −1
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ from .models import ( 
    OneToOneCategory, NullableName, ProxyCategory, SingleObject, RelatedObject,

    ModelA, ModelB, ModelC, ModelD, Responsibility, Job, JobResponsibilities,

    BaseA, FK1, Identifier, Program, Channel, Page, Paragraph, Chapter, Book,

    MyObject, Order, OrderItem)

    MyObject, Order, OrderItem, Task, Staff, StaffUser)





class BaseQuerysetTest(TestCase):
@@ -2943,3 +2943,23 @@ class RelatedLookupTypeTests(TestCase): 
        self.assertQuerysetEqual(

            ObjectB.objects.filter(objecta__in=[wrong_type]),

            [ob], lambda x: x)



class Ticket20955Tests(TestCase):

    def test_ticket_20955(self):

        jack = Staff.objects.create(name='jackstaff')

        jackstaff = StaffUser.objects.create(staff=jack)

        jill = Staff.objects.create(name='jillstaff')

        jillstaff = StaffUser.objects.create(staff=jill)

        task = Task.objects.create(creator=jackstaff, owner=jillstaff, title="task")

        task_get = Task.objects.get(pk=task.pk)

        # Load data so that assertNumQueries doesn't complain about the get

        # version's queries.

        task_get.creator.staffuser.staff

        task_get.owner.staffuser.staff

        task_select_related = Task.objects.select_related(

            'creator__staffuser__staff', 'owner__staffuser__staff').get(pk=task.pk)

        with self.assertNumQueries(0):

            self.assertEqual(task_select_related.creator.staffuser.staff,

                             task_get.creator.staffuser.staff)

            self.assertEqual(task_select_related.owner.staffuser.staff,

                             task_get.owner.staffuser.staff)