From ad4f59ab56abee086172185a06a71d348f708e93 Mon Sep 17 00:00:00 2001
From: AlexTate <0xalextate@gmail.com>
Date: Sun, 4 Dec 2022 12:37:55 -0700
Subject: [PATCH] gh-98458: unittest: bugfix for infinite loop while handling
chained exceptions that contain cycles (GH-98459)
* Bugfix addressing infinite loop while handling self-referencing chained exception in TestResult._clean_tracebacks()
* Bugfix extended to properly handle exception cycles in _clean_tracebacks. The "seen" set follows the approach used in the TracebackException class (thank you @iritkatriel for pointing it out)
* adds a test for a single chained exception that holds a self-loop in its __cause__ and __context__ attributes
(cherry picked from commit 72ec518203c3f3577a5e888b12f10bb49060e6c2)
Co-authored-by: AlexTate <0xalextate@gmail.com>
---
Lib/unittest/result.py | 4 +-
Lib/unittest/test/test_result.py | 56 +++++++++++++++++++
...2-10-19-18-31-53.gh-issue-98458.vwyq7O.rst | 1 +
3 files changed, 60 insertions(+), 1 deletion(-)
create mode 100644 Misc/NEWS.d/next/Library/2022-10-19-18-31-53.gh-issue-98458.vwyq7O.rst
diff --git a/Lib/unittest/result.py b/Lib/unittest/result.py
index 3da7005e603f4a..5ca4c23238b419 100644
--- a/Lib/unittest/result.py
+++ b/Lib/unittest/result.py
@@ -196,6 +196,7 @@ def _clean_tracebacks(self, exctype, value, tb, test):
ret = None
first = True
excs = [(exctype, value, tb)]
+ seen = {id(value)} # Detect loops in chained exceptions.
while excs:
(exctype, value, tb) = excs.pop()
# Skip test runner traceback levels
@@ -214,8 +215,9 @@ def _clean_tracebacks(self, exctype, value, tb, test):
if value is not None:
for c in (value.__cause__, value.__context__):
- if c is not None:
+ if c is not None and id(c) not in seen:
excs.append((type(c), c, c.__traceback__))
+ seen.add(id(c))
return ret
def _is_relevant_tb_level(self, tb):
diff --git a/Lib/unittest/test/test_result.py b/Lib/unittest/test/test_result.py
index b0cc3d867d6e57..9320b0a44b51f9 100644
--- a/Lib/unittest/test/test_result.py
+++ b/Lib/unittest/test/test_result.py
@@ -275,6 +275,62 @@ def get_exc_info():
self.assertEqual(len(dropped), 1)
self.assertIn("raise self.failureException(msg)", dropped[0])
+ def test_addFailure_filter_traceback_frames_chained_exception_self_loop(self):
+ class Foo(unittest.TestCase):
+ def test_1(self):
+ pass
+
+ def get_exc_info():
+ try:
+ loop = Exception("Loop")
+ loop.__cause__ = loop
+ loop.__context__ = loop
+ raise loop
+ except:
+ return sys.exc_info()
+
+ exc_info_tuple = get_exc_info()
+
+ test = Foo('test_1')
+ result = unittest.TestResult()
+ result.startTest(test)
+ result.addFailure(test, exc_info_tuple)
+ result.stopTest(test)
+
+ formatted_exc = result.failures[0][1]
+ self.assertEqual(formatted_exc.count("Exception: Loop\n"), 1)
+
+ def test_addFailure_filter_traceback_frames_chained_exception_cycle(self):
+ class Foo(unittest.TestCase):
+ def test_1(self):
+ pass
+
+ def get_exc_info():
+ try:
+ # Create two directionally opposed cycles
+ # __cause__ in one direction, __context__ in the other
+ A, B, C = Exception("A"), Exception("B"), Exception("C")
+ edges = [(C, B), (B, A), (A, C)]
+ for ex1, ex2 in edges:
+ ex1.__cause__ = ex2
+ ex2.__context__ = ex1
+ raise C
+ except:
+ return sys.exc_info()
+
+ exc_info_tuple = get_exc_info()
+
+ test = Foo('test_1')
+ result = unittest.TestResult()
+ result.startTest(test)
+ result.addFailure(test, exc_info_tuple)
+ result.stopTest(test)
+
+ formatted_exc = result.failures[0][1]
+ self.assertEqual(formatted_exc.count("Exception: A\n"), 1)
+ self.assertEqual(formatted_exc.count("Exception: B\n"), 1)
+ self.assertEqual(formatted_exc.count("Exception: C\n"), 1)
+
# "addError(test, err)"
# ...
# "Called when the test case test raises an unexpected exception err
diff --git a/Misc/NEWS.d/next/Library/2022-10-19-18-31-53.gh-issue-98458.vwyq7O.rst b/Misc/NEWS.d/next/Library/2022-10-19-18-31-53.gh-issue-98458.vwyq7O.rst
new file mode 100644
index 00000000000000..f74195cc8e7dc6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-10-19-18-31-53.gh-issue-98458.vwyq7O.rst
@@ -0,0 +1 @@
+Fix infinite loop in unittest when a self-referencing chained exception is raised
pFad - Phonifier reborn
Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.
Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.
Alternative Proxies:
Alternative Proxy
pFad Proxy
pFad v3 Proxy
pFad v4 Proxy