diff options
Diffstat (limited to 'Lib/asyncio/events.py')
| -rw-r--r-- | Lib/asyncio/events.py | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py index 6cff8c5..ce44942 100644 --- a/Lib/asyncio/events.py +++ b/Lib/asyncio/events.py @@ -619,7 +619,7 @@ class AbstractEventLoopPolicy: Returns an event loop object implementing the BaseEventLoop interface, or raises an exception in case no event loop has been set for the - current context. + current context and the current policy does not specify to create one. It should never return None.""" raise NotImplementedError @@ -672,6 +672,28 @@ class BaseDefaultEventLoopPolicy(AbstractEventLoopPolicy): Returns an instance of EventLoop or raises an exception. """ + if (self._local._loop is None and + not self._local._set_called and + threading.current_thread() is threading.main_thread()): + stacklevel = 2 + try: + f = sys._getframe(1) + except AttributeError: + pass + else: + # Move up the call stack so that the warning is attached + # to the line outside asyncio itself. + while f: + module = f.f_globals.get('__name__') + if not (module == 'asyncio' or module.startswith('asyncio.')): + break + f = f.f_back + stacklevel += 1 + import warnings + warnings.warn('There is no current event loop', + DeprecationWarning, stacklevel=stacklevel) + self.set_event_loop(self.new_event_loop()) + if self._local._loop is None: raise RuntimeError('There is no current event loop in thread %r.' % threading.current_thread().name) |