[Python-checkins] cpython (3.4): Closes #21886, #21447: Fix a race condition in asyncio when setting the result
victor.stinner
python-checkins at python.org
Sat Jul 5 15:31:26 CEST 2014
http://hg.python.org/cpython/rev/d7e4efd5e279
changeset: 91552:d7e4efd5e279
branch: 3.4
parent: 91550:6094aa25b33c
user: Victor Stinner <victor.stinner at gmail.com>
date: Sat Jul 05 15:29:41 2014 +0200
summary:
Closes #21886, #21447: Fix a race condition in asyncio when setting the result
of a Future with call_soon(). Add an helper, a private method, to set the
result only if the future was not cancelled.
files:
Lib/asyncio/coroutines.py | 6 ++++++
Lib/asyncio/futures.py | 6 ++++++
Lib/asyncio/proactor_events.py | 2 +-
Lib/asyncio/queues.py | 2 +-
Lib/asyncio/selector_events.py | 5 +++--
Lib/asyncio/tasks.py | 3 ++-
Lib/asyncio/unix_events.py | 4 ++--
Lib/test/test_asyncio/test_futures.py | 6 ++++++
Lib/test/test_asyncio/test_tasks.py | 4 ++++
9 files changed, 31 insertions(+), 7 deletions(-)
diff --git a/Lib/asyncio/coroutines.py b/Lib/asyncio/coroutines.py
--- a/Lib/asyncio/coroutines.py
+++ b/Lib/asyncio/coroutines.py
@@ -64,6 +64,12 @@
self.gen = gen
self.func = func
self._source_traceback = traceback.extract_stack(sys._getframe(1))
+ # __name__, __qualname__, __doc__ attributes are set by the coroutine()
+ # decorator
+
+ def __repr__(self):
+ return ('<%s %s>'
+ % (self.__class__.__name__, _format_coroutine(self)))
def __iter__(self):
return self
diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -316,6 +316,12 @@
# So-called internal methods (note: no set_running_or_notify_cancel()).
+ def _set_result_unless_cancelled(self, result):
+ """Helper setting the result only if the future was not cancelled."""
+ if self.cancelled():
+ return
+ self.set_result(result)
+
def set_result(self, result):
"""Mark the future done and set its result.
diff --git a/Lib/asyncio/proactor_events.py b/Lib/asyncio/proactor_events.py
--- a/Lib/asyncio/proactor_events.py
+++ b/Lib/asyncio/proactor_events.py
@@ -38,7 +38,7 @@
self._server.attach(self)
self._loop.call_soon(self._protocol.connection_made, self)
if waiter is not None:
- self._loop.call_soon(waiter.set_result, None)
+ self._loop.call_soon(waiter._set_result_unless_cancelled, None)
def _set_extra(self, sock):
self._extra['pipe'] = sock
diff --git a/Lib/asyncio/queues.py b/Lib/asyncio/queues.py
--- a/Lib/asyncio/queues.py
+++ b/Lib/asyncio/queues.py
@@ -173,7 +173,7 @@
# run, we need to defer the put for a tick to ensure that
# getters and putters alternate perfectly. See
# ChannelTest.test_wait.
- self._loop.call_soon(putter.set_result, None)
+ self._loop.call_soon(putter._set_result_unless_cancelled, None)
return self._get()
diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -481,7 +481,7 @@
self._loop.add_reader(self._sock_fd, self._read_ready)
self._loop.call_soon(self._protocol.connection_made, self)
if waiter is not None:
- self._loop.call_soon(waiter.set_result, None)
+ self._loop.call_soon(waiter._set_result_unless_cancelled, None)
def pause_reading(self):
if self._closing:
@@ -690,7 +690,8 @@
self._loop.add_reader(self._sock_fd, self._read_ready)
self._loop.call_soon(self._protocol.connection_made, self)
if self._waiter is not None:
- self._loop.call_soon(self._waiter.set_result, None)
+ self._loop.call_soon(self._waiter._set_result_unless_cancelled,
+ None)
def pause_reading(self):
# XXX This is a bit icky, given the comment at the top of
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -487,7 +487,8 @@
def sleep(delay, result=None, *, loop=None):
"""Coroutine that completes after a given time (in seconds)."""
future = futures.Future(loop=loop)
- h = future._loop.call_later(delay, future.set_result, result)
+ h = future._loop.call_later(delay,
+ future._set_result_unless_cancelled, result)
try:
return (yield from future)
finally:
diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py
--- a/Lib/asyncio/unix_events.py
+++ b/Lib/asyncio/unix_events.py
@@ -269,7 +269,7 @@
self._loop.add_reader(self._fileno, self._read_ready)
self._loop.call_soon(self._protocol.connection_made, self)
if waiter is not None:
- self._loop.call_soon(waiter.set_result, None)
+ self._loop.call_soon(waiter._set_result_unless_cancelled, None)
def _read_ready(self):
try:
@@ -353,7 +353,7 @@
self._loop.call_soon(self._protocol.connection_made, self)
if waiter is not None:
- self._loop.call_soon(waiter.set_result, None)
+ self._loop.call_soon(waiter._set_result_unless_cancelled, None)
def get_write_buffer_size(self):
return sum(len(data) for data in self._buffer)
diff --git a/Lib/test/test_asyncio/test_futures.py b/Lib/test/test_asyncio/test_futures.py
--- a/Lib/test/test_asyncio/test_futures.py
+++ b/Lib/test/test_asyncio/test_futures.py
@@ -343,6 +343,12 @@
message = m_log.error.call_args[0][0]
self.assertRegex(message, re.compile(regex, re.DOTALL))
+ def test_set_result_unless_cancelled(self):
+ fut = asyncio.Future(loop=self.loop)
+ fut.cancel()
+ fut._set_result_unless_cancelled(2)
+ self.assertTrue(fut.cancelled())
+
class FutureDoneCallbackTests(test_utils.TestCase):
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
@@ -211,6 +211,10 @@
coro = ('%s() at %s:%s'
% (coro_qualname, code.co_filename, code.co_firstlineno))
+ # test repr(CoroWrapper)
+ if coroutines._DEBUG:
+ self.assertEqual(repr(gen), '<CoroWrapper %s>' % coro)
+
# test pending Task
t = asyncio.Task(gen, loop=self.loop)
t.add_done_callback(Dummy())
--
Repository URL: http://hg.python.org/cpython
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