cpython/Lib/test/test_free_threading/test_sys.py
Victor Stinner b16d23fc9f
gh-151218: Replace sys.flags in PyConfig_Set() (#151402)
PyConfig_Set() and sys.set_int_max_str_digits() now replace
sys.flags (create a new object), instead of modifying sys.flags in-place.

Modifying sys.flags in-place can lead to data races when multiple
threads are reading or writing sys.flags in parallel.

Use _Py_atomic functions to get and set max_str_digits members.

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
2026-06-16 16:17:33 +00:00

28 lines
913 B
Python

import sys
import unittest
from test.support import threading_helper
class SysModuleTest(unittest.TestCase):
def test_int_max_str_digits_thread(self):
# gh-151218: Check that it's safe to call get_int_max_str_digits() and
# set_int_max_str_digits() in parallel. Previously, this test triggered
# warnings in TSan on a free threaded build.
old_limit = sys.get_int_max_str_digits()
self.addCleanup(sys.set_int_max_str_digits, old_limit)
def worker(worker_id):
if not worker_id:
for i in range (20_000):
sys.get_int_max_str_digits()
else:
for i in range (20_000):
sys.set_int_max_str_digits(4300 + (i & 7))
workers = [lambda: worker(i) for i in range(5)]
threading_helper.run_concurrently(workers)
if __name__ == "__main__":
unittest.main()