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Issue 44917: interpreter hangs on recursion in both body and handler of a try block

This was found while investigating issue44895. It may or may not be the cause of that issue.


The script below hangs on a mac (it's an extract from test_exceptions.test_recursion_in_except_handler).

-----------
import sys

count = 0
def main():

  def f():
    global count
    count += 1
    try:
        f()
    except RecursionError:
        f()

  sys.setrecursionlimit(30)

  try:
    f()
  except RecursionError:
    pass

main()
print(count)
-----------


When I kill it the traceback shows it alternating between the two recursive calls, but not in a regular pattern:


... [snipped a lot]

  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  [Previous line repeated 2 more times]
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  [Previous line repeated 1 more time]
RecursionError: maximum recursion depth exceeded

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/tt.py", line 22, in <module>
    main()
    ^^^^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 18, in main
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  [Previous line repeated 10 more times]
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 11, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 13, in f
    f()
    ^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 7, in f
    def f():
KeyboardInterrupt