Ticket #12953: 12953_r12557.diff

tests/regressiontests/delete_regress/models.py

@@ -3 +3 @@
 from django.db.models import sql, query
 from django.test import TransactionTestCase
 
+from django.contrib.contenttypes import generic
+from django.contrib.contenttypes.models import ContentType
+
+class Award(models.Model):
+    name = models.CharField(max_length=25)
+    object_id = models.PositiveIntegerField()
+    content_type = models.ForeignKey(ContentType)
+    content_object = generic.GenericForeignKey()
+
+class AwardNote(models.Model):
+    award = models.ForeignKey(Award)
+    note = models.CharField(max_length=100)
+
+class Person(models.Model):
+    name = models.CharField(max_length=25)
+    awards = generic.GenericRelation(Award)
+
 class Book(models.Model):
     pagecount = models.IntegerField()
 

new file tests/regressiontests/delete_regress/tests.py

@@ +1 @@
+from django.test import TestCase
+
+from models import Award, AwardNote, Person
+
+class DeleteCascadeTests(TestCase):
+    def test_generic_relation_cascade(self):
+        """
+        Test that Django cascades deletes through generic-related
+        objects to their reverse relations.
+        
+        This might falsely succeed if the database cascades deletes
+        itself immediately; the postgresql_psycopg2 backend does not
+        give such a false success because ForeignKeys are created with
+        DEFERRABLE INITIALLY DEFERRED, so its internal cascade is
+        delayed until transaction commit.
+
+        """
+        person = Person.objects.create(name='Nelson Mandela')
+        award = Award.objects.create(name='Nobel', content_object=person)
+        note = AwardNote.objects.create(note='a peace prize',
+                                        award=award)
+        self.assertEquals(AwardNote.objects.count(), 1)
+        person.delete()
+        self.assertEquals(Award.objects.count(), 0)
+        # first two asserts are just sanity checks, this is the kicker:
+        self.assertEquals(AwardNote.objects.count(), 0)
+