[Python-checkins] cpython (3.4): asyncio, Tulip issue 201: Fix a race condition in wait_for()
victor.stinner
python-checkins at python.org
Thu Aug 28 11:21:49 CEST 2014
http://hg.python.org/cpython/rev/20244eda2946
changeset: 92257:20244eda2946
branch: 3.4
parent: 92253:a48ef19911ea
user: Victor Stinner <victor.stinner at gmail.com>
date: Thu Aug 28 11:19:25 2014 +0200
summary:
asyncio, Tulip issue 201: Fix a race condition in wait_for()
Don't raise a TimeoutError if we reached the timeout and the future completed
in the same iteration of the event loop. A side effect of the bug is that
Queue.get() looses items.
files:
Lib/asyncio/tasks.py | 15 +++++++++------
Lib/test/test_asyncio/test_tasks.py | 15 +++++++++++++++
2 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -330,9 +330,9 @@
return (yield from _wait(fs, timeout, return_when, loop))
-def _release_waiter(waiter, value=True, *args):
+def _release_waiter(waiter, *args):
if not waiter.done():
- waiter.set_result(value)
+ waiter.set_result(None)
@coroutine
@@ -357,14 +357,17 @@
return (yield from fut)
waiter = futures.Future(loop=loop)
- timeout_handle = loop.call_later(timeout, _release_waiter, waiter, False)
- cb = functools.partial(_release_waiter, waiter, True)
+ timeout_handle = loop.call_later(timeout, _release_waiter, waiter)
+ cb = functools.partial(_release_waiter, waiter)
fut = async(fut, loop=loop)
fut.add_done_callback(cb)
try:
- if (yield from waiter):
+ # wait until the future completes or the timeout
+ yield from waiter
+
+ if fut.done():
return fut.result()
else:
fut.remove_done_callback(cb)
@@ -397,7 +400,7 @@
if timeout_handle is not None:
timeout_handle.cancel()
if not waiter.done():
- waiter.set_result(False)
+ waiter.set_result(None)
for f in fs:
f.add_done_callback(_on_completion)
diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -552,6 +552,21 @@
self.assertTrue(fut.done())
self.assertTrue(fut.cancelled())
+ def test_wait_for_race_condition(self):
+
+ def gen():
+ yield 0.1
+ yield 0.1
+ yield 0.1
+
+ loop = self.new_test_loop(gen)
+
+ fut = asyncio.Future(loop=loop)
+ task = asyncio.wait_for(fut, timeout=0.2, loop=loop)
+ loop.call_later(0.1, fut.set_result, "ok")
+ res = loop.run_until_complete(task)
+ self.assertEqual(res, "ok")
+
def test_wait(self):
def gen():
--
Repository URL: http://hg.python.org/cpython
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