Get the asyncio event loop in start() and not in __init()__

Fixes #484.

2 files changed, 10 insertions, 1 deletions

diff --git a/apscheduler/schedulers/asyncio.py b/apscheduler/schedulers/asyncio.py
index 289ef13..9ab7221 100644
--- a/apscheduler/schedulers/asyncio.py
+++ b/apscheduler/schedulers/asyncio.py
@@ -38,13 +38,19 @@ class AsyncIOScheduler(BaseScheduler):
     _eventloop = None
     _timeout = None
 
+    def start(self, paused=False):
+        if not self._eventloop:
+            self._eventloop = asyncio.get_event_loop()
+
+        super().start(paused)
+
     @run_in_event_loop
     def shutdown(self, wait=True):
         super(AsyncIOScheduler, self).shutdown(wait)
         self._stop_timer()
 
     def _configure(self, config):
-        self._eventloop = maybe_ref(config.pop('event_loop', None)) or asyncio.get_event_loop()
+        self._eventloop = maybe_ref(config.pop('event_loop', None))
         super(AsyncIOScheduler, self)._configure(config)
 
     def _start_timer(self, wait_seconds):
diff --git a/docs/versionhistory.rst b/docs/versionhistory.rst
index 578f496..772b520 100644
--- a/docs/versionhistory.rst
+++ b/docs/versionhistory.rst
@@ -12,6 +12,9 @@ APScheduler, see the :doc:`migration section <migration>`.
 * Pinned ``tzlocal`` to a version compatible with pytz
 * Ensured that jitter is always non-negative to prevent triggers from firing more often than
   intended
+* Changed ``AsyncIOScheduler`` to obtain the event loop in ``start()`` instead of ``__init__()``,
+  to prevent situations where the scheduler won't run because it's using a different event loop
+  than then one currently running
 * Made it possible to create weak references to ``Job`` instances
 * Fixed Zookeeper job store using backslashes instead of forward slashes for paths
   on Windows (PR by Laurel-rao)