from __future__ import unicode_literals from math import ceil from django.db import IntegrityError, connection, models from django.db.models.sql.constants import GET_ITERATOR_CHUNK_SIZE from django.test import TestCase, skipIfDBFeature, skipUnlessDBFeature from django.utils.six.moves import range from .models import ( A, M, MR, R, S, T, Avatar, Base, Child, HiddenUser, HiddenUserProfile, M2MFrom, M2MTo, MRNull, Parent, RChild, User, create_a, get_default_r, ) class OnDeleteTests(TestCase): def setUp(self): self.DEFAULT = get_default_r() def test_auto(self): a = create_a('auto') a.auto.delete() self.assertFalse(A.objects.filter(name='auto').exists()) def test_auto_nullable(self): a = create_a('auto_nullable') a.auto_nullable.delete() self.assertFalse(A.objects.filter(name='auto_nullable').exists()) def test_setvalue(self): a = create_a('setvalue') a.setvalue.delete() a = A.objects.get(pk=a.pk) self.assertEqual(self.DEFAULT, a.setvalue) def test_setnull(self): a = create_a('setnull') a.setnull.delete() a = A.objects.get(pk=a.pk) self.assertEqual(None, a.setnull) def test_setdefault(self): a = create_a('setdefault') a.setdefault.delete() a = A.objects.get(pk=a.pk) self.assertEqual(self.DEFAULT, a.setdefault) def test_setdefault_none(self): a = create_a('setdefault_none') a.setdefault_none.delete() a = A.objects.get(pk=a.pk) self.assertEqual(None, a.setdefault_none) def test_cascade(self): a = create_a('cascade') a.cascade.delete() self.assertFalse(A.objects.filter(name='cascade').exists()) def test_cascade_nullable(self): a = create_a('cascade_nullable') a.cascade_nullable.delete() self.assertFalse(A.objects.filter(name='cascade_nullable').exists()) def test_protect(self): a = create_a('protect') self.assertRaises(IntegrityError, a.protect.delete) def test_do_nothing(self): # Testing DO_NOTHING is a bit harder: It would raise IntegrityError for a normal model, # so we connect to pre_delete and set the fk to a known value. replacement_r = R.objects.create() def check_do_nothing(sender, **kwargs): obj = kwargs['instance'] obj.donothing_set.update(donothing=replacement_r) models.signals.pre_delete.connect(check_do_nothing) a = create_a('do_nothing') a.donothing.delete() a = A.objects.get(pk=a.pk) self.assertEqual(replacement_r, a.donothing) models.signals.pre_delete.disconnect(check_do_nothing) def test_do_nothing_qscount(self): """ Test that a models.DO_NOTHING relation doesn't trigger a query. """ b = Base.objects.create() with self.assertNumQueries(1): # RelToBase should not be queried. b.delete() self.assertEqual(Base.objects.count(), 0) def test_inheritance_cascade_up(self): child = RChild.objects.create() child.delete() self.assertFalse(R.objects.filter(pk=child.pk).exists()) def test_inheritance_cascade_down(self): child = RChild.objects.create() parent = child.r_ptr parent.delete() self.assertFalse(RChild.objects.filter(pk=child.pk).exists()) def test_cascade_from_child(self): a = create_a('child') a.child.delete() self.assertFalse(A.objects.filter(name='child').exists()) self.assertFalse(R.objects.filter(pk=a.child_id).exists()) def test_cascade_from_parent(self): a = create_a('child') R.objects.get(pk=a.child_id).delete() self.assertFalse(A.objects.filter(name='child').exists()) self.assertFalse(RChild.objects.filter(pk=a.child_id).exists()) def test_setnull_from_child(self): a = create_a('child_setnull') a.child_setnull.delete() self.assertFalse(R.objects.filter(pk=a.child_setnull_id).exists()) a = A.objects.get(pk=a.pk) self.assertEqual(None, a.child_setnull) def test_setnull_from_parent(self): a = create_a('child_setnull') R.objects.get(pk=a.child_setnull_id).delete() self.assertFalse(RChild.objects.filter(pk=a.child_setnull_id).exists()) a = A.objects.get(pk=a.pk) self.assertEqual(None, a.child_setnull) def test_o2o_setnull(self): a = create_a('o2o_setnull') a.o2o_setnull.delete() a = A.objects.get(pk=a.pk) self.assertEqual(None, a.o2o_setnull) class DeletionTests(TestCase): def test_m2m(self): m = M.objects.create() r = R.objects.create() MR.objects.create(m=m, r=r) r.delete() self.assertFalse(MR.objects.exists()) r = R.objects.create() MR.objects.create(m=m, r=r) m.delete() self.assertFalse(MR.objects.exists()) m = M.objects.create() r = R.objects.create() m.m2m.add(r) r.delete() through = M._meta.get_field('m2m').rel.through self.assertFalse(through.objects.exists()) r = R.objects.create() m.m2m.add(r) m.delete() self.assertFalse(through.objects.exists()) m = M.objects.create() r = R.objects.create() MRNull.objects.create(m=m, r=r) r.delete() self.assertFalse(not MRNull.objects.exists()) self.assertFalse(m.m2m_through_null.exists()) def test_bulk(self): s = S.objects.create(r=R.objects.create()) for i in range(2 * GET_ITERATOR_CHUNK_SIZE): T.objects.create(s=s) # 1 (select related `T` instances) # + 1 (select related `U` instances) # + 2 (delete `T` instances in batches) # + 1 (delete `s`) self.assertNumQueries(5, s.delete) self.assertFalse(S.objects.exists()) def test_instance_update(self): deleted = [] related_setnull_sets = [] def pre_delete(sender, **kwargs): obj = kwargs['instance'] deleted.append(obj) if isinstance(obj, R): related_setnull_sets.append(list(a.pk for a in obj.setnull_set.all())) models.signals.pre_delete.connect(pre_delete) a = create_a('update_setnull') a.setnull.delete() a = create_a('update_cascade') a.cascade.delete() for obj in deleted: self.assertEqual(None, obj.pk) for pk_list in related_setnull_sets: for a in A.objects.filter(id__in=pk_list): self.assertEqual(None, a.setnull) models.signals.pre_delete.disconnect(pre_delete) def test_deletion_order(self): pre_delete_order = [] post_delete_order = [] def log_post_delete(sender, **kwargs): pre_delete_order.append((sender, kwargs['instance'].pk)) def log_pre_delete(sender, **kwargs): post_delete_order.append((sender, kwargs['instance'].pk)) models.signals.post_delete.connect(log_post_delete) models.signals.pre_delete.connect(log_pre_delete) r = R.objects.create(pk=1) s1 = S.objects.create(pk=1, r=r) s2 = S.objects.create(pk=2, r=r) T.objects.create(pk=1, s=s1) T.objects.create(pk=2, s=s2) r.delete() self.assertEqual( pre_delete_order, [(T, 2), (T, 1), (S, 2), (S, 1), (R, 1)] ) self.assertEqual( post_delete_order, [(T, 1), (T, 2), (S, 1), (S, 2), (R, 1)] ) models.signals.post_delete.disconnect(log_post_delete) models.signals.pre_delete.disconnect(log_pre_delete) def test_relational_post_delete_signals_happen_before_parent_object(self): deletions = [] def log_post_delete(instance, **kwargs): self.assertTrue(R.objects.filter(pk=instance.r_id)) self.assertIs(type(instance), S) deletions.append(instance.id) r = R.objects.create(pk=1) S.objects.create(pk=1, r=r) models.signals.post_delete.connect(log_post_delete, sender=S) try: r.delete() finally: models.signals.post_delete.disconnect(log_post_delete) self.assertEqual(len(deletions), 1) self.assertEqual(deletions[0], 1) @skipUnlessDBFeature("can_defer_constraint_checks") def test_can_defer_constraint_checks(self): u = User.objects.create( avatar=Avatar.objects.create() ) a = Avatar.objects.get(pk=u.avatar_id) # 1 query to find the users for the avatar. # 1 query to delete the user # 1 query to delete the avatar # The important thing is that when we can defer constraint checks there # is no need to do an UPDATE on User.avatar to null it out. # Attach a signal to make sure we will not do fast_deletes. calls = [] def noop(*args, **kwargs): calls.append('') models.signals.post_delete.connect(noop, sender=User) self.assertNumQueries(3, a.delete) self.assertFalse(User.objects.exists()) self.assertFalse(Avatar.objects.exists()) self.assertEqual(len(calls), 1) models.signals.post_delete.disconnect(noop, sender=User) @skipIfDBFeature("can_defer_constraint_checks") def test_cannot_defer_constraint_checks(self): u = User.objects.create( avatar=Avatar.objects.create() ) # Attach a signal to make sure we will not do fast_deletes. calls = [] def noop(*args, **kwargs): calls.append('') models.signals.post_delete.connect(noop, sender=User) a = Avatar.objects.get(pk=u.avatar_id) # The below doesn't make sense... Why do we need to null out # user.avatar if we are going to delete the user immediately after it, # and there are no more cascades. # 1 query to find the users for the avatar. # 1 query to delete the user # 1 query to null out user.avatar, because we can't defer the constraint # 1 query to delete the avatar self.assertNumQueries(4, a.delete) self.assertFalse(User.objects.exists()) self.assertFalse(Avatar.objects.exists()) self.assertEqual(len(calls), 1) models.signals.post_delete.disconnect(noop, sender=User) def test_hidden_related(self): r = R.objects.create() h = HiddenUser.objects.create(r=r) HiddenUserProfile.objects.create(user=h) r.delete() self.assertEqual(HiddenUserProfile.objects.count(), 0) def test_large_delete(self): TEST_SIZE = 2000 objs = [Avatar() for i in range(0, TEST_SIZE)] Avatar.objects.bulk_create(objs) # Calculate the number of queries needed. batch_size = connection.ops.bulk_batch_size(['pk'], objs) # The related fetches are done in batches. batches = int(ceil(float(len(objs)) / batch_size)) # One query for Avatar.objects.all() and then one related fast delete for # each batch. fetches_to_mem = 1 + batches # The Avatar objects are going to be deleted in batches of GET_ITERATOR_CHUNK_SIZE queries = fetches_to_mem + TEST_SIZE // GET_ITERATOR_CHUNK_SIZE self.assertNumQueries(queries, Avatar.objects.all().delete) self.assertFalse(Avatar.objects.exists()) def test_large_delete_related(self): TEST_SIZE = 2000 s = S.objects.create(r=R.objects.create()) for i in range(TEST_SIZE): T.objects.create(s=s) batch_size = max(connection.ops.bulk_batch_size(['pk'], range(TEST_SIZE)), 1) # TEST_SIZE // batch_size (select related `T` instances) # + 1 (select related `U` instances) # + TEST_SIZE // GET_ITERATOR_CHUNK_SIZE (delete `T` instances in batches) # + 1 (delete `s`) expected_num_queries = (ceil(TEST_SIZE // batch_size) + ceil(TEST_SIZE // GET_ITERATOR_CHUNK_SIZE) + 2) self.assertNumQueries(expected_num_queries, s.delete) self.assertFalse(S.objects.exists()) self.assertFalse(T.objects.exists()) def test_delete_with_keeping_parents(self): child = RChild.objects.create() parent_id = child.r_ptr_id child.delete(keep_parents=True) self.assertFalse(RChild.objects.filter(id=child.id).exists()) self.assertTrue(R.objects.filter(id=parent_id).exists()) class FastDeleteTests(TestCase): def test_fast_delete_fk(self): u = User.objects.create( avatar=Avatar.objects.create() ) a = Avatar.objects.get(pk=u.avatar_id) # 1 query to fast-delete the user # 1 query to delete the avatar self.assertNumQueries(2, a.delete) self.assertFalse(User.objects.exists()) self.assertFalse(Avatar.objects.exists()) def test_fast_delete_m2m(self): t = M2MTo.objects.create() f = M2MFrom.objects.create() f.m2m.add(t) # 1 to delete f, 1 to fast-delete m2m for f self.assertNumQueries(2, f.delete) def test_fast_delete_revm2m(self): t = M2MTo.objects.create() f = M2MFrom.objects.create() f.m2m.add(t) # 1 to delete t, 1 to fast-delete t's m_set self.assertNumQueries(2, f.delete) def test_fast_delete_qs(self): u1 = User.objects.create() u2 = User.objects.create() self.assertNumQueries(1, User.objects.filter(pk=u1.pk).delete) self.assertEqual(User.objects.count(), 1) self.assertTrue(User.objects.filter(pk=u2.pk).exists()) def test_fast_delete_joined_qs(self): a = Avatar.objects.create(desc='a') User.objects.create(avatar=a) u2 = User.objects.create() expected_queries = 1 if connection.features.update_can_self_select else 2 self.assertNumQueries(expected_queries, User.objects.filter(avatar__desc='a').delete) self.assertEqual(User.objects.count(), 1) self.assertTrue(User.objects.filter(pk=u2.pk).exists()) def test_fast_delete_inheritance(self): c = Child.objects.create() p = Parent.objects.create() # 1 for self, 1 for parent # However, this doesn't work as child.parent access creates a query, # and this means we will be generating extra queries (a lot for large # querysets). This is not a fast-delete problem. # self.assertNumQueries(2, c.delete) c.delete() self.assertFalse(Child.objects.exists()) self.assertEqual(Parent.objects.count(), 1) self.assertEqual(Parent.objects.filter(pk=p.pk).count(), 1) # 1 for self delete, 1 for fast delete of empty "child" qs. self.assertNumQueries(2, p.delete) self.assertFalse(Parent.objects.exists()) # 1 for self delete, 1 for fast delete of empty "child" qs. c = Child.objects.create() p = c.parent_ptr self.assertNumQueries(2, p.delete) self.assertFalse(Parent.objects.exists()) self.assertFalse(Child.objects.exists()) def test_fast_delete_large_batch(self): User.objects.bulk_create(User() for i in range(0, 2000)) # No problems here - we aren't going to cascade, so we will fast # delete the objects in a single query. self.assertNumQueries(1, User.objects.all().delete) a = Avatar.objects.create(desc='a') User.objects.bulk_create(User(avatar=a) for i in range(0, 2000)) # We don't hit parameter amount limits for a, so just one query for # that + fast delete of the related objs. self.assertNumQueries(2, a.delete) self.assertEqual(User.objects.count(), 0)