Use threading.Event rather than boolean flag.

Lib/test/test_free_threading/test_set.py

@@ -1,5 +1,5 @@
 import unittest
-from threading import Thread, Barrier
+from threading import Thread, Barrier, Event
 from test.support import threading_helper
 
 
@@ -38,19 +38,18 @@ def test_contains_mutate(self):
         """Test set contains operation combined with mutation."""
         barrier = Barrier(2, timeout=2)
         s = set()
-        done = False
+        done = Event()
 
         NUM_LOOPS = 1000
 
         def read_set():
             barrier.wait()
-            while not done:
+            while not done.is_set():
                 for i in range(self.SET_SIZE):
                     item = i >> 1
                     result = item in s
 
         def mutate_set():
-            nonlocal done
             barrier.wait()
             for i in range(NUM_LOOPS):
                 s.clear()
@@ -60,7 +59,7 @@ def mutate_set():
                     s.discard(j)
                 # executes the set_swap_bodies() function
                 s.__iand__(set(k for k in range(10, 20)))
-            done = True
+            done.set()
 
         threads = [Thread(target=read_set), Thread(target=mutate_set)]
         for t in threads:
@@ -70,7 +69,7 @@ def mutate_set():
 
     def test_contains_frozenset(self):
         barrier = Barrier(3, timeout=2)
-        done = False
+        done = Event()
 
         NUM_LOOPS = 1_000
 
@@ -80,20 +79,19 @@ def test_contains_frozenset(self):
 
         def mutate_set():
             barrier.wait()
-            while not done:
+            while not done.is_set():
                 s.add(0)
                 s.add(1)
                 s.clear()
 
         def read_set():
-            nonlocal done
             barrier.wait()
             container = frozenset([frozenset([0])])
             self.assertTrue(set([0]) in container)
             for _ in range(NUM_LOOPS):
                 # Will return True when {0} is the key and False otherwise
                 result = s in container
-            done = True
+            done.set()
 
         threads = [
             Thread(target=read_set),