[Python-checkins] bpo-41891: ensure asyncio.wait_for waits for task completion (GH-22461)
miss-islington
webhook-mailer at python.org
Fri Dec 18 12:45:33 EST 2020
https://github.com/python/cpython/commit/a3dec9d8ec5ae142946ff6b94947a183d7c48f35
commit: a3dec9d8ec5ae142946ff6b94947a183d7c48f35
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2020-12-18T09:45:24-08:00
summary:
bpo-41891: ensure asyncio.wait_for waits for task completion (GH-22461)
(cherry picked from commit 17ef4319a34f5a2f95e7823dfb5f5b8cff11882d)
Co-authored-by: Richard Kojedzinszky <rkojedzinszky at users.noreply.github.com>
files:
A Lib/test/test_asyncio/test_asyncio_waitfor.py
A Misc/NEWS.d/next/Library/2020-09-30-13-35-29.bpo-41891.pNAeYI.rst
M Lib/asyncio/tasks.py
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 1fa76a161e1e4..7094132583814 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -484,7 +484,10 @@ async def wait_for(fut, timeout, *, loop=None):
return fut.result()
else:
fut.remove_done_callback(cb)
- fut.cancel()
+ # We must ensure that the task is not running
+ # after wait_for() returns.
+ # See https://bugs.python.org/issue32751
+ await _cancel_and_wait(fut, loop=loop)
raise
if fut.done():
diff --git a/Lib/test/test_asyncio/test_asyncio_waitfor.py b/Lib/test/test_asyncio/test_asyncio_waitfor.py
new file mode 100644
index 0000000000000..2ca64abbeb527
--- /dev/null
+++ b/Lib/test/test_asyncio/test_asyncio_waitfor.py
@@ -0,0 +1,61 @@
+import asyncio
+import unittest
+import time
+
+def tearDownModule():
+ asyncio.set_event_loop_policy(None)
+
+
+class SlowTask:
+ """ Task will run for this defined time, ignoring cancel requests """
+ TASK_TIMEOUT = 0.2
+
+ def __init__(self):
+ self.exited = False
+
+ async def run(self):
+ exitat = time.monotonic() + self.TASK_TIMEOUT
+
+ while True:
+ tosleep = exitat - time.monotonic()
+ if tosleep <= 0:
+ break
+
+ try:
+ await asyncio.sleep(tosleep)
+ except asyncio.CancelledError:
+ pass
+
+ self.exited = True
+
+class AsyncioWaitForTest(unittest.TestCase):
+
+ async def atest_asyncio_wait_for_cancelled(self):
+ t = SlowTask()
+
+ waitfortask = asyncio.create_task(asyncio.wait_for(t.run(), t.TASK_TIMEOUT * 2))
+ await asyncio.sleep(0)
+ waitfortask.cancel()
+ await asyncio.wait({waitfortask})
+
+ self.assertTrue(t.exited)
+
+ def test_asyncio_wait_for_cancelled(self):
+ asyncio.run(self.atest_asyncio_wait_for_cancelled())
+
+ async def atest_asyncio_wait_for_timeout(self):
+ t = SlowTask()
+
+ try:
+ await asyncio.wait_for(t.run(), t.TASK_TIMEOUT / 2)
+ except asyncio.TimeoutError:
+ pass
+
+ self.assertTrue(t.exited)
+
+ def test_asyncio_wait_for_timeout(self):
+ asyncio.run(self.atest_asyncio_wait_for_timeout())
+
+
+if __name__ == '__main__':
+ unittest.main()
diff --git a/Misc/NEWS.d/next/Library/2020-09-30-13-35-29.bpo-41891.pNAeYI.rst b/Misc/NEWS.d/next/Library/2020-09-30-13-35-29.bpo-41891.pNAeYI.rst
new file mode 100644
index 0000000000000..75c2512780315
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-09-30-13-35-29.bpo-41891.pNAeYI.rst
@@ -0,0 +1 @@
+Ensure asyncio.wait_for waits for task completion
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