Issue #18418: After fork(), reinit all threads states, not only active ones.
Patch by A. Jesse Jiryu Davis.
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index ef04cd3..5a765f3 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -443,6 +443,29 @@
self.assertEqual(out, '')
self.assertEqual(err, '')
+ @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
+ def test_is_alive_after_fork(self):
+ # Try hard to trigger #18418: is_alive() could sometimes be True on
+ # threads that vanished after a fork.
+ old_interval = sys.getcheckinterval()
+
+ # Make the bug more likely to manifest.
+ sys.setcheckinterval(10)
+
+ try:
+ for i in range(20):
+ t = threading.Thread(target=lambda: None)
+ t.start()
+ pid = os.fork()
+ if pid == 0:
+ os._exit(1 if t.is_alive() else 0)
+ else:
+ t.join()
+ pid, status = os.waitpid(pid, 0)
+ self.assertEqual(0, status)
+ finally:
+ sys.setcheckinterval(old_interval)
+
class ThreadJoinOnShutdown(BaseTestCase):