bpo-30727: Fix a race condition in test_threading. (#2334)
diff --git a/Lib/test/lock_tests.py b/Lib/test/lock_tests.py
index a6cb3b1..4fa154f 100644
--- a/Lib/test/lock_tests.py
+++ b/Lib/test/lock_tests.py
@@ -461,21 +461,28 @@
# construct. In particular, it is possible that this can no longer
# be conveniently guaranteed should their implementation ever change.
N = 5
+ ready = []
results1 = []
results2 = []
phase_num = 0
def f():
cond.acquire()
+ ready.append(phase_num)
result = cond.wait()
cond.release()
results1.append((result, phase_num))
cond.acquire()
+ ready.append(phase_num)
result = cond.wait()
cond.release()
results2.append((result, phase_num))
b = Bunch(f, N)
b.wait_for_started()
- _wait()
+ # first wait, to ensure all workers settle into cond.wait() before
+ # we continue. See issues #8799 and #30727.
+ while len(ready) < 5:
+ _wait()
+ ready.clear()
self.assertEqual(results1, [])
# Notify 3 threads at first
cond.acquire()
@@ -487,9 +494,9 @@
_wait()
self.assertEqual(results1, [(True, 1)] * 3)
self.assertEqual(results2, [])
- # first wait, to ensure all workers settle into cond.wait() before
- # we continue. See issue #8799
- _wait()
+ # make sure all awaken workers settle into cond.wait()
+ while len(ready) < 3:
+ _wait()
# Notify 5 threads: they might be in their first or second wait
cond.acquire()
cond.notify(5)
@@ -500,7 +507,9 @@
_wait()
self.assertEqual(results1, [(True, 1)] * 3 + [(True, 2)] * 2)
self.assertEqual(results2, [(True, 2)] * 3)
- _wait() # make sure all workers settle into cond.wait()
+ # make sure all workers settle into cond.wait()
+ while len(ready) < 5:
+ _wait()
# Notify all threads: they are all in their second wait
cond.acquire()
cond.notify_all()