From bc174e6ea0ce676c5a7f467bda9739e6ef6b6186 Mon Sep 17 00:00:00 2001
From: Petter Friberg <petter_friberg@hotmail.com>
Date: Tue, 4 Jan 2022 23:06:46 +0100
Subject: Fixed #33410 -- Fixed recursive capturing of callbacks by
 TestCase.captureOnCommitCallbacks().

Regression in d89f976bddb49fb168334960acc8979c3de991fa.
---
 tests/test_utils/tests.py | 52 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

(limited to 'tests/test_utils')

diff --git a/tests/test_utils/tests.py b/tests/test_utils/tests.py
index 2addc1fdde..3380a1c67e 100644
--- a/tests/test_utils/tests.py
+++ b/tests/test_utils/tests.py
@@ -1829,6 +1829,58 @@ class CaptureOnCommitCallbacksTests(TestCase):
         self.assertEqual(len(callbacks), 2)
         self.assertIs(self.callback_called, True)
 
+    def test_execute_tree(self):
+        """
+        A visualisation of the callback tree tested. Each node is expected to
+        be visited only once:
+
+        └─branch_1
+          ├─branch_2
+          │ ├─leaf_1
+          │ └─leaf_2
+          └─leaf_3
+        """
+        branch_1_call_counter = 0
+        branch_2_call_counter = 0
+        leaf_1_call_counter = 0
+        leaf_2_call_counter = 0
+        leaf_3_call_counter = 0
+
+        def leaf_1():
+            nonlocal leaf_1_call_counter
+            leaf_1_call_counter += 1
+
+        def leaf_2():
+            nonlocal leaf_2_call_counter
+            leaf_2_call_counter += 1
+
+        def leaf_3():
+            nonlocal leaf_3_call_counter
+            leaf_3_call_counter += 1
+
+        def branch_1():
+            nonlocal branch_1_call_counter
+            branch_1_call_counter += 1
+            transaction.on_commit(branch_2)
+            transaction.on_commit(leaf_3)
+
+        def branch_2():
+            nonlocal branch_2_call_counter
+            branch_2_call_counter += 1
+            transaction.on_commit(leaf_1)
+            transaction.on_commit(leaf_2)
+
+        with self.captureOnCommitCallbacks(execute=True) as callbacks:
+            transaction.on_commit(branch_1)
+
+        self.assertEqual(branch_1_call_counter, 1)
+        self.assertEqual(branch_2_call_counter, 1)
+        self.assertEqual(leaf_1_call_counter, 1)
+        self.assertEqual(leaf_2_call_counter, 1)
+        self.assertEqual(leaf_3_call_counter, 1)
+
+        self.assertEqual(callbacks, [branch_1, branch_2, leaf_3, leaf_1, leaf_2])
+
 
 class DisallowedDatabaseQueriesTests(SimpleTestCase):
     def test_disallowed_database_connections(self):
-- 
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