[Python-checkins] cpython (merge 3.4 -> 3.5): asyncio: Make ensure_future() accept all kinds of awaitables.

Fri Oct 2 15:10:08 EDT 2015

https://hg.python.org/cpython/rev/901537ff7f80
changeset: 98487:901537ff7f80
branch: 3.5
parent: 98482:3b565295eba0
parent: 98486:b40a61e79893
user: Yury Selivanov <yselivanov at sprymix.com>
date: Fri Oct 02 15:05:59 2015 -0400
summary:
 asyncio: Make ensure_future() accept all kinds of awaitables.
files:
 Doc/whatsnew/3.5.rst | 7 ++++++
 Lib/asyncio/tasks.py | 16 +++++++++++++-
 Lib/test/test_asyncio/test_tasks.py | 18 +++++++++++++++++
 Misc/NEWS | 2 +
 4 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -803,6 +803,13 @@
 :class:`asyncio.Queue` class.
 (Contributed by Victor Stinner.)
 
+Updates in 3.5.1:
+
+* The :func:`~asyncio.ensure_future` function and all functions that
+ use it, such as :meth:`loop.run_until_complete() <asyncio.BaseEventLoop.run_until_complete>`,
+ now accept all kinds of :term:`awaitable objects <awaitable>`.
+ (Contributed by Yury Selivanov.)
+
 
 bz2
 ---
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -512,7 +512,7 @@
 
 
 def ensure_future(coro_or_future, *, loop=None):
- """Wrap a coroutine in a future.
+ """Wrap a coroutine or an awaitable in a future.
 
 If the argument is a Future, it is returned directly.
 """
@@ -527,8 +527,20 @@
 if task._source_traceback:
 del task._source_traceback[-1]
 return task
+ elif compat.PY35 and inspect.isawaitable(coro_or_future):
+ return ensure_future(_wrap_awaitable(coro_or_future), loop=loop)
 else:
- raise TypeError('A Future or coroutine is required')
+ raise TypeError('A Future, a coroutine or an awaitable is required')
+
+
+ at coroutine
+def _wrap_awaitable(awaitable):
+ """Helper for asyncio.ensure_future().
+
+ Wraps awaitable (an object with __await__) into a coroutine
+ that will later be wrapped in a Task by ensure_future().
+ """
+ return (yield from awaitable.__await__())
 
 
 class _GatheringFuture(futures.Future):
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
@@ -153,6 +153,24 @@
 t = asyncio.ensure_future(t_orig, loop=self.loop)
 self.assertIs(t, t_orig)
 
+ @unittest.skipUnless(PY35, 'need python 3.5 or later')
+ def test_ensure_future_awaitable(self):
+ class Aw:
+ def __init__(self, coro):
+ self.coro = coro
+ def __await__(self):
+ return (yield from self.coro)
+
+ @asyncio.coroutine
+ def coro():
+ return 'ok'
+
+ loop = asyncio.new_event_loop()
+ self.set_event_loop(loop)
+ fut = asyncio.ensure_future(Aw(coro()), loop=loop)
+ loop.run_until_complete(fut)
+ assert fut.result() == 'ok'
+
 def test_ensure_future_neither(self):
 with self.assertRaises(TypeError):
 asyncio.ensure_future('ok')
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -152,6 +152,8 @@
 - Issue #23572: Fixed functools.singledispatch on classes with falsy
 metaclasses. Patch by Ethan Furman.
 
+- asyncio: ensure_future() now accepts awaitable objects.
+
 IDLE
 ----
 
-- 
Repository URL: https://hg.python.org/cpython
