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 https://github.com/python/cpython/pull/23568

The root cause seems to be the same as #42500, so I'm going to backport https://github.com/python/cpython/pull/23568 to 3.9

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