<unittest> AssertRaises() causes core dump in handling recursion

@terryjreedy

BPO	43185
Nosy	@terryjreedy, @markshannon, @iritkatriel, @CharlesFengY
Superseder	bpo-45806: Cannot Recover From StackOverflow in 3.9 Tests

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/markshannon'
closed_at = <Date 2021-11-19.18:15:58.815>
created_at = <Date 2021-02-10.09:00:08.810>
labels = ['interpreter-core', '3.9', 'type-crash']
title = '<unittest> AssertRaises() causes core dump in handling recursion'
updated_at = <Date 2021-11-19.18:15:58.815>
user = 'https://github.com/CharlesFengY'

bugs.python.org fields:

activity = <Date 2021-11-19.18:15:58.815>
actor = 'lukasz.langa'
assignee = 'Mark.Shannon'
closed = True
closed_date = <Date 2021-11-19.18:15:58.815>
closer = 'lukasz.langa'
components = ['Interpreter Core']
creation = <Date 2021-02-10.09:00:08.810>
creator = 'CharlesFengY'
dependencies = []
files = []
hgrepos = []
issue_num = 43185
keywords = []
message_count = 7.0
messages = ['386763', '386775', '386776', '386777', '386778', '386779', '386910']
nosy_count = 4.0
nosy_names = ['terry.reedy', 'Mark.Shannon', 'iritkatriel', 'CharlesFengY']
pr_nums = []
priority = 'normal'
resolution = 'out of date'
stage = 'resolved'
status = 'closed'
superseder = '45806'
type = 'crash'
url = 'https://bugs.python.org/issue43185'
versions = ['Python 3.9']

Seeing the following program, in the second assertRaises(), function "test_invalid_adpcm_state()" is recursively called. Then a fatal Python error shows up and the Python interpreter crashes.

++++++++++++++++++++++++++++++++++++++
import unittest
import audioop

class TestAudioop(unittest.TestCase):
         pass

def test_invalid_adpcm_state():
         TestAudioop.assertRaises(TypeError, audioop.lin2adpcm, b'\x00', 1, 555)
         TestAudioop.assertRaises(test_invalid_adpcm_state(), audioop.adpcm2lin, b'\x00', 1, (0, (- 1)))

TestAudioop = TestAudioop()
test_invalid_adpcm_state()

+++++++++++++++++++++++++++++++++++++++

System Info: Ubuntu 16.04
Python Version: Python 3.9.1

Reproduced on master as well. Simplified script:

------------------------------------------

import unittest

def f():
    raise TypeError

class TestAudioop(unittest.TestCase):
    def test_invalid_adpcm_state(self):
        self.assertRaises(TypeError, f) 
        self.test_invalid_adpcm_state()

TestAudioop().test_invalid_adpcm_state()

------------------------------------------

Could you please tell me your secret method of getting the minimal script?
I will try to provide minimal ones in our following work.

3.9 crashes.
On master, I'm not seeing a crash, just a RecursionError.

>>> import unittest
>>> 
>>> def f():
...     raise TypeError
... 
>>> class TestAudioop(unittest.TestCase):
...     def test_invalid_adpcm_state(self):
...         self.assertRaises(TypeError, f) 
...         self.test_invalid_adpcm_state()
... 
>>> TestAudioop().test_invalid_adpcm_state()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 4, in test_invalid_adpcm_state
  File "<stdin>", line 4, in test_invalid_adpcm_state
  File "<stdin>", line 4, in test_invalid_adpcm_state
  [Previous line repeated 992 more times]
  File "<stdin>", line 3, in test_invalid_adpcm_state
  File "/home/mark/repos/cpython/Lib/unittest/case.py", line 730, in assertRaises
    context = _AssertRaisesContext(expected_exception, self)
  File "/home/mark/repos/cpython/Lib/unittest/case.py", line 168, in __init__
    _BaseTestCaseContext.__init__(self, test_case)
RecursionError: maximum recursion depth exceeded

Yang - no secret really, just trial and error.
Mark - right I wasn't on master, sorry.

I think this was fixed by #23568

The root cause seems to be the same as bpo-42500, so I'm going to backport #23568 to 3.9

bpo-43186, bpo-43187 also have recursive code that fails in 3.9 and recovers in 3.10. Am closing them in favor of this. Also suspect bpo-43188, bpo-43189, bpo-43190 are duplicates. Yang, recheck after Mark does the backport here.

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<unittest> AssertRaises() causes core dump in handling recursion #87351

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<unittest> AssertRaises() causes core dump in handling recursion #87351

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CharlesFengY commented on Feb 10, 2021

iritkatriel commented on Feb 10, 2021

CharlesFengY commented on Feb 10, 2021

markshannon commented on Feb 10, 2021

iritkatriel commented on Feb 10, 2021

markshannon commented on Feb 10, 2021

terryjreedy commented on Feb 13, 2021

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