[2.0.x] Fixed #28722 -- Made QuerySet.reverse() affect nulls_first/nulls_last.

Backport of 21a3a29dc9 from master

AUTHORS

@@ -790,6 +790,7 @@ answer newbie questions, and generally made Django that much better:
     Tomáš Kopeček <permonik@m6.cz>
     Tome Cvitan <tome@cvitan.com>
     Tomek Paczkowski <tomek@hauru.eu>
+    Tomer Chachamu
     Tommy Beadle <tbeadle@gmail.com>
     Tore Lundqvist <tore.lundqvist@gmail.com>
     torne-django@wolfpuppy.org.uk

django/db/models/expressions.py

@@ -1144,6 +1144,9 @@ class OrderBy(BaseExpression):
 
     def reverse_ordering(self):
         self.descending = not self.descending
+        if self.nulls_first or self.nulls_last:
+            self.nulls_first = not self.nulls_first
+            self.nulls_last = not self.nulls_last
         return self
 
     def asc(self):

docs/releases/1.11.7.txt

@@ -13,3 +13,6 @@ Bugfixes
   argument is a callable that returns ``None`` (:ticket:`28601`).
 
 * Fixed the Basque ``DATE_FORMAT`` string (:ticket:`28710`).
+
+* Made ``QuerySet.reverse()`` affect ``nulls_first`` and ``nulls_last``
+  (:ticket:`28722`).

tests/ordering/tests.py

@@ -92,24 +92,28 @@ class OrderingTests(TestCase):
         with self.assertRaisesMessage(ValueError, msg):
             Article.objects.order_by(F("author").desc(nulls_last=True, nulls_first=True))
 
+    def assertQuerysetEqualReversible(self, queryset, sequence):
+        self.assertSequenceEqual(queryset, sequence)
+        self.assertSequenceEqual(queryset.reverse(), list(reversed(sequence)))
+
     def test_order_by_nulls_last(self):
         Article.objects.filter(headline="Article 3").update(author=self.author_1)
         Article.objects.filter(headline="Article 4").update(author=self.author_2)
         # asc and desc are chainable with nulls_last.
-        self.assertSequenceEqual(
-            Article.objects.order_by(F("author").desc(nulls_last=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(F("author").desc(nulls_last=True), 'headline'),
             [self.a4, self.a3, self.a1, self.a2],
         )
-        self.assertSequenceEqual(
-            Article.objects.order_by(F("author").asc(nulls_last=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(F("author").asc(nulls_last=True), 'headline'),
             [self.a3, self.a4, self.a1, self.a2],
         )
-        self.assertSequenceEqual(
-            Article.objects.order_by(Upper("author__name").desc(nulls_last=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(Upper("author__name").desc(nulls_last=True), 'headline'),
             [self.a4, self.a3, self.a1, self.a2],
         )
-        self.assertSequenceEqual(
-            Article.objects.order_by(Upper("author__name").asc(nulls_last=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(Upper("author__name").asc(nulls_last=True), 'headline'),
             [self.a3, self.a4, self.a1, self.a2],
         )
 
@@ -117,20 +121,20 @@ class OrderingTests(TestCase):
         Article.objects.filter(headline="Article 3").update(author=self.author_1)
         Article.objects.filter(headline="Article 4").update(author=self.author_2)
         # asc and desc are chainable with nulls_first.
-        self.assertSequenceEqual(
-            Article.objects.order_by(F("author").asc(nulls_first=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(F("author").asc(nulls_first=True), 'headline'),
             [self.a1, self.a2, self.a3, self.a4],
         )
-        self.assertSequenceEqual(
-            Article.objects.order_by(F("author").desc(nulls_first=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(F("author").desc(nulls_first=True), 'headline'),
             [self.a1, self.a2, self.a4, self.a3],
         )
-        self.assertSequenceEqual(
-            Article.objects.order_by(Upper("author__name").asc(nulls_first=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(Upper("author__name").asc(nulls_first=True), 'headline'),
             [self.a1, self.a2, self.a3, self.a4],
         )
-        self.assertSequenceEqual(
-            Article.objects.order_by(Upper("author__name").desc(nulls_first=True)),
+        self.assertQuerysetEqualReversible(
+            Article.objects.order_by(Upper("author__name").desc(nulls_first=True), 'headline'),
             [self.a1, self.a2, self.a4, self.a3],
         )