Refs #18682 -- Edited explanation in stale content type deletion.

Follow up to 8db889ea.

django/contrib/contenttypes/management.py

@@ -154,22 +154,20 @@ def update_contenttypes(app_config, verbosity=2, interactive=True, using=DEFAULT
                 for obj_type, objs in collector.data.items():
                     if objs == {ct}:
                         continue
-                    ct_info.append('    - %s object%s of type %s.%s:' % (
+                    ct_info.append('    - %s %s object(s)' % (
                         len(objs),
-                        's' if len(objs) != 1 else '',
-                        obj_type._meta.app_label,
-                        obj_type._meta.model_name)
-                    )
+                        obj_type._meta.label,
+                    ))
 
             content_type_display = '\n'.join(ct_info)
             print("""Some content types in your database are stale and can be deleted.
-Any objects that depend on these content types will then also be deleted.
-The content types, and the dependent objects that would be deleted, are:
+Any objects that depend on these content types will also be deleted.
+The content types and dependent objects that would be deleted are:
 
 %s
 
-This list does not include data that might be in your database
-outside of Django's models.
+This list doesn't include any cascade deletions to data outside of Django's
+models (uncommon).
 
 Are you sure you want to delete these content types?
 If you're unsure, answer 'no'.
@@ -191,7 +189,6 @@ If you're unsure, answer 'no'.
 class NoFastDeleteCollector(Collector):
     def can_fast_delete(self, *args, **kwargs):
         """
-        We always want to load the objects into memory so that we can display
-        them to the user when asking confirmation.
+        Always load related objects to display them when showing confirmation.
         """
         return False

docs/releases/1.11.txt

@@ -87,10 +87,9 @@ Minor features
 :mod:`django.contrib.contenttypes`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-* When stale content types are detected during a management command, there is
-  now an expansive list of objects that will be deleted. Previously, only
-  the content type objects themselves were listed, even if there were objects
-  with foreign keys towards the content types that would be deleted also.
+* When stale content types are detected after the ``migrate`` command, there's
+  now a list of related objects such as ``auth.Permission``\s that will also be
+  deleted. Previously, only the content types were listed.
 
 :mod:`django.contrib.gis`
 ~~~~~~~~~~~~~~~~~~~~~~~~~

tests/contenttypes_tests/models.py

@@ -131,6 +131,7 @@ class Post(models.Model):
 class ModelWithNullFKToSite(models.Model):
     title = models.CharField(max_length=200)
     site = models.ForeignKey(Site, null=True, on_delete=models.CASCADE)
+    post = models.ForeignKey(Post, null=True, on_delete=models.CASCADE)
 
     def __str__(self):
         return self.title

tests/contenttypes_tests/tests.py

@@ -389,21 +389,27 @@ class UpdateContentTypesTests(TestCase):
     def test_interactive_true_with_dependent_objects(self):
         """
         interactive mode of update_contenttypes() (the default) should delete
-        stale contenttypes and warn of dependent objects
+        stale contenttypes and warn of dependent objects.
         """
-        Post.objects.create(title='post', content_type=self.content_type)
+        post = Post.objects.create(title='post', content_type=self.content_type)
+        # A related object is needed to show that a custom collector with
+        # can_fast_delete=False is needed.
+        ModelWithNullFKToSite.objects.create(post=post)
         contenttypes_management.input = lambda x: force_str("yes")
         with captured_stdout() as stdout:
             contenttypes_management.update_contenttypes(self.app_config)
         self.assertEqual(Post.objects.count(), 0)
-        self.assertIn("1 object of type contenttypes_tests.post:", stdout.getvalue())
-        self.assertIn("Deleting stale content type", stdout.getvalue())
+        output = stdout.getvalue()
+        self.assertIn('- Content type for contenttypes_tests.Fake', output)
+        self.assertIn('- 1 contenttypes_tests.Post object(s)', output)
+        self.assertIn('- 1 contenttypes_tests.ModelWithNullFKToSite', output)
+        self.assertIn('Deleting stale content type', output)
         self.assertEqual(ContentType.objects.count(), self.before_count)
 
     def test_interactive_true_without_dependent_objects(self):
         """
         interactive mode of update_contenttypes() (the default) should delete
-        stale contenttypes and inform there are no dependent objects
+        stale contenttypes even if there aren't any dependent objects.
         """
         contenttypes_management.input = lambda x: force_str("yes")
         with captured_stdout() as stdout: