[5.2.x] Fixed #36290 -- Made TupleIn() lookup discard tuples containing None.

Just like the In() lookup discards of None members TupleIn() should
discard tuples containing any None as NULL != NULL in SQL and the
framework expects such queries to be elided under some circumstances.

Refs #31667, #36116.

Thanks Basptise Mispelon for bisecting the regression to 626d77e.

Backport of f7f38f3a0b44d8c6d14344dae66b6ce52cd77b55 from main

django/db/models/fields/tuple_lookups.py

@@ -318,6 +318,10 @@ class TupleIn(TupleLookupMixin, In):
         lhs = self.lhs
 
         for vals in rhs:
+            # Remove any tuple containing None from the list as NULL is never
+            # equal to anything.
+            if any(val is None for val in vals):
+                continue
             result.append(
                 Tuple(
                     *[
@@ -327,6 +331,9 @@ class TupleIn(TupleLookupMixin, In):
                 )
             )
 
+        if not result:
+            raise EmptyResultSet
+
         return compiler.compile(Tuple(*result))
 
     def get_fallback_sql(self, compiler, connection):
@@ -342,9 +349,15 @@ class TupleIn(TupleLookupMixin, In):
         lhs = self.lhs
 
         for vals in rhs:
+            # Remove any tuple containing None from the list as NULL is never
+            # equal to anything.
+            if any(val is None for val in vals):
+                continue
             lookups = [Exact(col, val) for col, val in zip(lhs, vals)]
             root.children.append(WhereNode(lookups, connector=AND))
 
+        if not root.children:
+            raise EmptyResultSet
         return root.as_sql(compiler, connection)
 
 

docs/releases/5.2.1.txt

@@ -12,3 +12,6 @@ Bugfixes
 * Fixed a regression in Django 5.2 that caused a crash when annotating
   aggregate expressions over query that uses explicit grouping by transforms
   followed by field references (:ticket:`36292`).
+
+* Fixed a regression in Django 5.2 that caused unnecessary queries when
+  prefetching nullable foreign key relationships (:ticket:`36290`).

tests/composite_pk/test_filter.py

@@ -206,6 +206,13 @@ class CompositePKFilterTests(TestCase):
             [self.comment_1],
         )
 
+    def test_filter_by_pk_in_none(self):
+        with self.assertNumQueries(0):
+            self.assertSequenceEqual(
+                Comment.objects.filter(pk__in=[(None, 1), (1, None)]),
+                [],
+            )
+
     def test_filter_comments_by_user_and_order_by_pk_asc(self):
         self.assertSequenceEqual(
             Comment.objects.filter(user=self.user_1).order_by("pk"),

tests/foreign_object/models/person.py

@@ -84,7 +84,7 @@ class Friendship(models.Model):
     )
     from_friend_id = models.IntegerField()
     to_friend_country_id = models.IntegerField()
-    to_friend_id = models.IntegerField()
+    to_friend_id = models.IntegerField(null=True)
 
     # Relation Fields
     from_friend = models.ForeignObject(

tests/foreign_object/tests.py

@@ -297,6 +297,19 @@ class MultiColumnFKTests(TestCase):
             self.assertEqual(friendships[0].to_friend, self.george)
             self.assertEqual(friendships[1].to_friend, self.sam)
 
+    def test_prefetch_foreignobject_null_hidden_forward_skipped(self):
+        fiendship = Friendship.objects.create(
+            from_friend_country=self.usa,
+            from_friend_id=self.bob.id,
+            to_friend_country_id=self.usa.id,
+            to_friend_id=None,
+        )
+        with self.assertNumQueries(1):
+            self.assertEqual(
+                Friendship.objects.prefetch_related("to_friend").get(),
+                fiendship,
+            )
+
     def test_prefetch_foreignobject_reverse(self):
         Membership.objects.create(
             membership_country=self.usa, person=self.bob, group=self.cia