[1.11.x] Fixed #28109 -- Corrected the stack level of unordered queryset pagination warnings.

Refs #26290.

Thanks Tim for the review.

Backport of c0f12a098c from master

django/core/paginator.py

@@ -109,7 +109,8 @@ class Paginator(object):
             warnings.warn(
                 'Pagination may yield inconsistent results with an unordered '
                 'object_list: {!r}'.format(self.object_list),
-                UnorderedObjectListWarning
+                UnorderedObjectListWarning,
+                stacklevel=3
             )
 
 

docs/releases/1.11.1.txt

@@ -49,3 +49,6 @@ Bugfixes
 * Fixed a regression where ``CheckboxSelectMultiple``, ``NullBooleanSelect``,
   ``RadioSelect``, ``SelectMultiple``, and ``Select`` localized option values
   (:ticket:`28075`).
+
+* Corrected the stack level of unordered queryset pagination warnings
+  (:ticket:`28109`).

tests/pagination/tests.py

@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 
 import unittest
+import warnings
 from datetime import datetime
 
 from django.core.paginator import (
@@ -321,12 +322,20 @@ class ModelPaginationTests(TestCase):
         self.assertIsInstance(p.object_list, list)
 
     def test_paginating_unordered_queryset_raises_warning(self):
-        msg = (
+        with warnings.catch_warnings(record=True) as warns:
+            # Prevent the RuntimeWarning subclass from appearing as an
+            # exception due to the warnings.simplefilter() in runtests.py.
+            warnings.filterwarnings('always', category=UnorderedObjectListWarning)
+            Paginator(Article.objects.all(), 5)
+        self.assertEqual(len(warns), 1)
+        warning = warns[0]
+        self.assertEqual(str(warning.message), (
             "Pagination may yield inconsistent results with an unordered "
             "object_list: <QuerySet [<Article: Article 1>, "
             "<Article: Article 2>, <Article: Article 3>, <Article: Article 4>, "
             "<Article: Article 5>, <Article: Article 6>, <Article: Article 7>, "
             "<Article: Article 8>, <Article: Article 9>]>"
-        )
-        with self.assertRaisesMessage(UnorderedObjectListWarning, msg):
-            Paginator(Article.objects.all(), 5)
+        ))
+        # The warning points at the Paginator caller (i.e. the stacklevel
+        # is appropriate).
+        self.assertEqual(warning.filename, __file__)