[3.2.x] Fixed #32717 -- Fixed filtering of querysets combined with the | operator.

Address a long standing bug in a Where.add optimization to discard
equal nodes that was surfaced by implementing equality for Lookup
instances in bbf141bcdc.

Thanks Shaheed Haque for the report.

Backport of b81c7562fc from main

django/utils/tree.py

@@ -90,7 +90,7 @@ class Node:
         If `squash` is False the data is prepared and added as a child to
         this tree without further logic.
         """
-        if data in self.children:
+        if self.connector == conn_type and data in self.children:
             return data
         if not squash:
             self.children.append(data)

docs/releases/3.2.3.txt

@@ -10,3 +10,6 @@ Bugfixes
 ========
 
 * Prepared for ``mysqlclient`` > 2.0.3 support (:ticket:`32732`).
+
+* Fixed a regression in Django 3.2 that caused the incorrect filtering of
+  querysets combined with the ``|`` operator (:ticket:`32717`).

tests/queries/tests.py

@@ -1338,6 +1338,10 @@ class Queries4Tests(TestCase):
         self.assertEqual(len(combined), 1)
         self.assertEqual(combined[0].name, 'a1')
 
+    def test_combine_or_filter_reuse(self):
+        combined = Author.objects.filter(name='a1') | Author.objects.filter(name='a3')
+        self.assertEqual(combined.get(name='a1'), self.a1)
+
     def test_join_reuse_order(self):
         # Join aliases are reused in order. This shouldn't raise AssertionError
         # because change_map contains a circular reference (#26522).

tests/utils_tests/test_tree.py

@@ -57,6 +57,11 @@ class NodeTests(unittest.TestCase):
         self.assertEqual(len(self.node1) + 1, len(node3))
         self.assertEqual(str(node3), "(DEFAULT: ('a', 1), ('b', 2), ('c', 3))")
 
+    def test_add_eq_child_mixed_connector(self):
+        node = Node(['a', 'b'], 'OR')
+        self.assertEqual(node.add('a', 'AND'), 'a')
+        self.assertEqual(node, Node([Node(['a', 'b'], 'OR'), 'a'], 'AND'))
+
     def test_negate(self):
         # negated is False by default
         self.assertFalse(self.node1.negated)