Ticket #14325: fix_genericforeignkey_comparison_and_add_regressiontest.diff

django/contrib/contenttypes/generic.py

@@ -49 +49 @@
         # Convenience function using get_model avoids a circular import when
         # using this model
         ContentType = get_model("contenttypes", "contenttype")
-        if obj:
+        if obj is not None:
              return ContentType.objects.db_manager(obj._state.db).get_for_model(obj)
-        elif id:
+        elif id is not None:
              return ContentType.objects.db_manager(using).get_for_id(id)
         else:
             # This should never happen. I love comments like this, don't you?

tests/regressiontests/generic_relations_regress/models.py

@@ -4 +4 @@
 
 __all__ = ('Link', 'Place', 'Restaurant', 'Person', 'Address', 
            'CharLink', 'TextLink', 'OddRelation1', 'OddRelation2', 
-           'Contact', 'Organization', 'Note')
+           'Contact', 'Organization', 'Note', 'Meeting')
 
 class Link(models.Model):
     content_type = models.ForeignKey(ContentType)
@@ -77 +77 @@
     name = models.CharField(max_length=255)
     contacts = models.ManyToManyField(Contact, related_name='organizations')
 
+class Meeting(models.Model):
+    name = models.CharField(max_length=100)
+
+    def __len__(self):
+        return 0
+

tests/regressiontests/generic_relations_regress/tests.py

@@ -70 +70 @@
             Q(notes__note__icontains=r'other note'))
         self.assertTrue(org_contact in qs)
 
+    def test_not_null_comparison(self):
+        """
+        Tests if an object which is logical False can be assigned to a
+        GenericForeignKey
 
+        Tests for bug http://code.djangoproject.com/ticket/14325
+        """
+        meeting = Meeting.objects.create(name='empty meeting')
+        link = Link(content_object=meeting)