Ticket #17838: fix_and_test_ticket17838.diff

django/contrib/contenttypes/generic.py

@@ -92 +92 @@
             if ct_id is None:
                 return None
             else:
-                return (getattr(obj, self.fk_field),
-                        self.get_content_type(id=ct_id,
-                                              using=obj._state.db).model_class())
+                return (obj.__class__._meta.pk.get_prep_value(getattr(obj, self.fk_field)),\
+                        self.get_content_type(id=ct_id, using=obj._state.db).model_class())
 
         return (ret_val,
                 lambda obj: (obj._get_pk_val(), obj.__class__),

tests/modeltests/prefetch_related/models.py

@@ -125 +125 @@
     tags = generic.GenericRelation(TaggedItem)
 
 
+class Comment(models.Model):
+    comment = models.TextField()
+
+    # Content-object field
+    content_type   = models.ForeignKey(ContentType)
+    object_pk      = models.TextField()
+    content_object = generic.GenericForeignKey(ct_field="content_type", fk_field="object_pk")
+
+
 ## Models for lookup ordering tests
 
 

tests/modeltests/prefetch_related/tests.py

@@ -5 +5 @@
 
 from .models import (Author, Book, Reader, Qualification, Teacher, Department,
     TaggedItem, Bookmark, AuthorAddress, FavoriteAuthors, AuthorWithAge,
-    BookWithYear, Person, House, Room, Employee)
+    BookWithYear, Person, House, Room, Employee, Comment)
 
 
 class PrefetchRelatedTests(TestCase):
@@ -254 +254 @@
             qs = TaggedItem.objects.prefetch_related('content_object')
             list(qs)
 
+    def test_prefetch_GFK_nonint_pk(self):
+        Comment.objects.create(comment="awesome", content_object=self.book1)
+
+        # 1 for Comment table, 1 for Book table
+        with self.assertNumQueries(2):
+            qs = Comment.objects.prefetch_related('content_object')
+            [c.content_object for c in qs]
+
     def test_traverse_GFK(self):
         """
         Test that we can traverse a 'content_object' with prefetch_related() and

tests/regressiontests/comment_tests/tests/model_tests.py

@@ -49 +49 @@
         author_comments = list(Comment.objects.for_model(Author.objects.get(pk=1)))
         self.assertEqual(article_comments, [c1, c3])
         self.assertEqual(author_comments, [c2])
+
+    def testPrefetchRelated(self):
+        c1, c2, c3, c4 = self.createSomeComments()
+        # one for comments, one for Articles, one for Author
+        with self.assertNumQueries(3):
+            qs = Comment.objects.prefetch_related('content_object')
+            [c.content_object for c in qs]