django/tests/delete_regress/tests.py

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import datetime
from django.db import connection, models, transaction
from django.test import TestCase, TransactionTestCase, skipUnlessDBFeature
from .models import (
Award, AwardNote, Book, Child, Eaten, Email, File, Food, FooFile,
FooFileProxy, FooImage, FooPhoto, House, Image, Item, Location, Login,
OrderedPerson, OrgUnit, Person, Photo, PlayedWith, PlayedWithNote, Policy,
Researcher, Toy, Version,
)
# Can't run this test under SQLite, because you can't
# get two connections to an in-memory database.
@skipUnlessDBFeature('test_db_allows_multiple_connections')
class DeleteLockingTest(TransactionTestCase):
available_apps = ['delete_regress']
def setUp(self):
# Create a second connection to the default database
self.conn2 = connection.copy()
self.conn2.set_autocommit(False)
def tearDown(self):
# Close down the second connection.
self.conn2.rollback()
self.conn2.close()
def test_concurrent_delete(self):
"""Concurrent deletes don't collide and lock the database (#9479)."""
with transaction.atomic():
Book.objects.create(id=1, pagecount=100)
Book.objects.create(id=2, pagecount=200)
Book.objects.create(id=3, pagecount=300)
with transaction.atomic():
# Start a transaction on the main connection.
self.assertEqual(3, Book.objects.count())
# Delete something using another database connection.
with self.conn2.cursor() as cursor2:
cursor2.execute("DELETE from delete_regress_book WHERE id = 1")
self.conn2.commit()
# In the same transaction on the main connection, perform a
# queryset delete that covers the object deleted with the other
# connection. This causes an infinite loop under MySQL InnoDB
# unless we keep track of already deleted objects.
Book.objects.filter(pagecount__lt=250).delete()
self.assertEqual(1, Book.objects.count())
class DeleteCascadeTests(TestCase):
def test_generic_relation_cascade(self):
"""
Django cascades deletes through generic-related objects to their
reverse relations.
"""
person = Person.objects.create(name='Nelson Mandela')
award = Award.objects.create(name='Nobel', content_object=person)
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AwardNote.objects.create(note='a peace prize',
award=award)
self.assertEqual(AwardNote.objects.count(), 1)
person.delete()
self.assertEqual(Award.objects.count(), 0)
# first two asserts are just sanity checks, this is the kicker:
self.assertEqual(AwardNote.objects.count(), 0)
def test_fk_to_m2m_through(self):
"""
If an M2M relationship has an explicitly-specified through model, and
some other model has an FK to that through model, deletion is cascaded
from one of the participants in the M2M, to the through model, to its
related model.
"""
juan = Child.objects.create(name='Juan')
paints = Toy.objects.create(name='Paints')
played = PlayedWith.objects.create(child=juan, toy=paints,
date=datetime.date.today())
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PlayedWithNote.objects.create(played=played,
note='the next Jackson Pollock')
self.assertEqual(PlayedWithNote.objects.count(), 1)
paints.delete()
self.assertEqual(PlayedWith.objects.count(), 0)
# first two asserts just sanity checks, this is the kicker:
self.assertEqual(PlayedWithNote.objects.count(), 0)
def test_15776(self):
policy = Policy.objects.create(pk=1, policy_number="1234")
version = Version.objects.create(policy=policy)
location = Location.objects.create(version=version)
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Item.objects.create(version=version, location=location)
policy.delete()
class DeleteCascadeTransactionTests(TransactionTestCase):
available_apps = ['delete_regress']
def test_inheritance(self):
"""
Auto-created many-to-many through tables referencing a parent model are
correctly found by the delete cascade when a child of that parent is
deleted.
Refs #14896.
"""
r = Researcher.objects.create()
email = Email.objects.create(
label="office-email", email_address="carl@science.edu"
)
r.contacts.add(email)
email.delete()
def test_to_field(self):
"""
Cascade deletion works with ForeignKey.to_field set to non-PK.
"""
apple = Food.objects.create(name="apple")
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Eaten.objects.create(food=apple, meal="lunch")
apple.delete()
self.assertFalse(Food.objects.exists())
self.assertFalse(Eaten.objects.exists())
class LargeDeleteTests(TestCase):
def test_large_deletes(self):
"Regression for #13309 -- if the number of objects > chunk size, deletion still occurs"
for x in range(300):
Book.objects.create(pagecount=x + 100)
# attach a signal to make sure we will not fast-delete
def noop(*args, **kwargs):
pass
models.signals.post_delete.connect(noop, sender=Book)
Book.objects.all().delete()
models.signals.post_delete.disconnect(noop, sender=Book)
self.assertEqual(Book.objects.count(), 0)
class ProxyDeleteTest(TestCase):
"""
Tests on_delete behavior for proxy models.
See #16128.
"""
def create_image(self):
"""Return an Image referenced by both a FooImage and a FooFile."""
# Create an Image
test_image = Image()
test_image.save()
foo_image = FooImage(my_image=test_image)
foo_image.save()
# Get the Image instance as a File
test_file = File.objects.get(pk=test_image.pk)
foo_file = FooFile(my_file=test_file)
foo_file.save()
return test_image
def test_delete_proxy(self):
"""
Deleting the *proxy* instance bubbles through to its non-proxy and
*all* referring objects are deleted.
"""
self.create_image()
Image.objects.all().delete()
# An Image deletion == File deletion
self.assertEqual(len(Image.objects.all()), 0)
self.assertEqual(len(File.objects.all()), 0)
# The Image deletion cascaded and *all* references to it are deleted.
self.assertEqual(len(FooImage.objects.all()), 0)
self.assertEqual(len(FooFile.objects.all()), 0)
def test_delete_proxy_of_proxy(self):
"""
Deleting a proxy-of-proxy instance should bubble through to its proxy
and non-proxy parents, deleting *all* referring objects.
"""
test_image = self.create_image()
# Get the Image as a Photo
test_photo = Photo.objects.get(pk=test_image.pk)
foo_photo = FooPhoto(my_photo=test_photo)
foo_photo.save()
Photo.objects.all().delete()
# A Photo deletion == Image deletion == File deletion
self.assertEqual(len(Photo.objects.all()), 0)
self.assertEqual(len(Image.objects.all()), 0)
self.assertEqual(len(File.objects.all()), 0)
# The Photo deletion should have cascaded and deleted *all*
# references to it.
self.assertEqual(len(FooPhoto.objects.all()), 0)
self.assertEqual(len(FooFile.objects.all()), 0)
self.assertEqual(len(FooImage.objects.all()), 0)
def test_delete_concrete_parent(self):
"""
Deleting an instance of a concrete model should also delete objects
referencing its proxy subclass.
"""
self.create_image()
File.objects.all().delete()
# A File deletion == Image deletion
self.assertEqual(len(File.objects.all()), 0)
self.assertEqual(len(Image.objects.all()), 0)
# The File deletion should have cascaded and deleted *all* references
# to it.
self.assertEqual(len(FooFile.objects.all()), 0)
self.assertEqual(len(FooImage.objects.all()), 0)
def test_delete_proxy_pair(self):
"""
If a pair of proxy models are linked by an FK from one concrete parent
to the other, deleting one proxy model cascade-deletes the other, and
the deletion happens in the right order (not triggering an
IntegrityError on databases unable to defer integrity checks).
Refs #17918.
"""
# Create an Image (proxy of File) and FooFileProxy (proxy of FooFile,
# which has an FK to File)
image = Image.objects.create()
as_file = File.objects.get(pk=image.pk)
FooFileProxy.objects.create(my_file=as_file)
Image.objects.all().delete()
self.assertEqual(len(FooFileProxy.objects.all()), 0)
def test_19187_values(self):
with self.assertRaises(TypeError):
Image.objects.values().delete()
with self.assertRaises(TypeError):
Image.objects.values_list().delete()
class Ticket19102Tests(TestCase):
"""
Test different queries which alter the SELECT clause of the query. We
also must be using a subquery for the deletion (that is, the original
query has a join in it). The deletion should be done as "fast-path"
deletion (that is, just one query for the .delete() call).
Note that .values() is not tested here on purpose. .values().delete()
doesn't work for non fast-path deletes at all.
"""
def setUp(self):
self.o1 = OrgUnit.objects.create(name='o1')
self.o2 = OrgUnit.objects.create(name='o2')
self.l1 = Login.objects.create(description='l1', orgunit=self.o1)
self.l2 = Login.objects.create(description='l2', orgunit=self.o2)
@skipUnlessDBFeature("update_can_self_select")
def test_ticket_19102_annotate(self):
with self.assertNumQueries(1):
Login.objects.order_by('description').filter(
orgunit__name__isnull=False
).annotate(
n=models.Count('description')
).filter(
n=1, pk=self.l1.pk
).delete()
self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())
@skipUnlessDBFeature("update_can_self_select")
def test_ticket_19102_extra(self):
with self.assertNumQueries(1):
Login.objects.order_by('description').filter(
orgunit__name__isnull=False
).extra(
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select={'extraf': '1'}
).filter(
pk=self.l1.pk
).delete()
self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())
@skipUnlessDBFeature("update_can_self_select")
@skipUnlessDBFeature('can_distinct_on_fields')
def test_ticket_19102_distinct_on(self):
# Both Login objs should have same description so that only the one
# having smaller PK will be deleted.
Login.objects.update(description='description')
with self.assertNumQueries(1):
Login.objects.distinct('description').order_by('pk').filter(
orgunit__name__isnull=False
).delete()
# Assumed that l1 which is created first has smaller PK.
self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())
@skipUnlessDBFeature("update_can_self_select")
def test_ticket_19102_select_related(self):
with self.assertNumQueries(1):
Login.objects.filter(
pk=self.l1.pk
).filter(
orgunit__name__isnull=False
).order_by(
'description'
).select_related('orgunit').delete()
self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())
@skipUnlessDBFeature("update_can_self_select")
def test_ticket_19102_defer(self):
with self.assertNumQueries(1):
Login.objects.filter(
pk=self.l1.pk
).filter(
orgunit__name__isnull=False
).order_by(
'description'
).only('id').delete()
self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())
class OrderedDeleteTests(TestCase):
def test_meta_ordered_delete(self):
# When a subquery is performed by deletion code, the subquery must be
# cleared of all ordering. There was a but that caused _meta ordering
# to be used. Refs #19720.
h = House.objects.create(address='Foo')
OrderedPerson.objects.create(name='Jack', lives_in=h)
OrderedPerson.objects.create(name='Bob', lives_in=h)
OrderedPerson.objects.filter(lives_in__address='Foo').delete()
self.assertEqual(OrderedPerson.objects.count(), 0)