bpo-39529: Deprecate creating new event loop in asyncio.get_event_loop() (GH-23554)
asyncio.get_event_loop() emits now a deprecation warning when it creates a new event loop.
In future releases it will became an alias of asyncio.get_running_loop().
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 52f1e66..9a9d0d6 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -549,7 +549,7 @@ def as_completed(fs, *, timeout=None):
from .queues import Queue # Import here to avoid circular import problem.
done = Queue()
- loop = events.get_event_loop()
+ loop = events._get_event_loop()
todo = {ensure_future(f, loop=loop) for f in set(fs)}
timeout_handle = None
@@ -616,23 +616,26 @@ def ensure_future(coro_or_future, *, loop=None):
If the argument is a Future, it is returned directly.
"""
- if coroutines.iscoroutine(coro_or_future):
- if loop is None:
- loop = events.get_event_loop()
- task = loop.create_task(coro_or_future)
- if task._source_traceback:
- del task._source_traceback[-1]
- return task
- elif futures.isfuture(coro_or_future):
+ return _ensure_future(coro_or_future, loop=loop)
+
+
+def _ensure_future(coro_or_future, *, loop=None):
+ if futures.isfuture(coro_or_future):
if loop is not None and loop is not futures._get_loop(coro_or_future):
raise ValueError('The future belongs to a different loop than '
- 'the one specified as the loop argument')
+ 'the one specified as the loop argument')
return coro_or_future
- elif inspect.isawaitable(coro_or_future):
- return ensure_future(_wrap_awaitable(coro_or_future), loop=loop)
- else:
- raise TypeError('An asyncio.Future, a coroutine or an awaitable is '
- 'required')
+
+ if not coroutines.iscoroutine(coro_or_future):
+ if inspect.isawaitable(coro_or_future):
+ coro_or_future = _wrap_awaitable(coro_or_future)
+ else:
+ raise TypeError('An asyncio.Future, a coroutine or an awaitable '
+ 'is required')
+
+ if loop is None:
+ loop = events._get_event_loop(stacklevel=4)
+ return loop.create_task(coro_or_future)
@types.coroutine
@@ -655,7 +658,8 @@ class _GatheringFuture(futures.Future):
cancelled.
"""
- def __init__(self, children, *, loop=None):
+ def __init__(self, children, *, loop):
+ assert loop is not None
super().__init__(loop=loop)
self._children = children
self._cancel_requested = False
@@ -706,7 +710,7 @@ def gather(*coros_or_futures, return_exceptions=False):
gather won't cancel any other awaitables.
"""
if not coros_or_futures:
- loop = events.get_event_loop()
+ loop = events._get_event_loop()
outer = loop.create_future()
outer.set_result([])
return outer
@@ -773,7 +777,7 @@ def _done_callback(fut):
loop = None
for arg in coros_or_futures:
if arg not in arg_to_fut:
- fut = ensure_future(arg, loop=loop)
+ fut = _ensure_future(arg, loop=loop)
if loop is None:
loop = futures._get_loop(fut)
if fut is not arg:
@@ -823,7 +827,7 @@ def shield(arg):
except CancelledError:
res = None
"""
- inner = ensure_future(arg)
+ inner = _ensure_future(arg)
if inner.done():
# Shortcut.
return inner