Fix timeout management on message delivery

hbmqtt/client.py

@@ -330,7 +330,10 @@ class MQTTClient:
         deliver_task = ensure_future(self._handler.mqtt_deliver_next_message(), loop=self._loop)
         self.client_tasks.append(deliver_task)
         self.logger.debug("Waiting message delivery")
-        yield from asyncio.wait([deliver_task], loop=self._loop, return_when=asyncio.FIRST_EXCEPTION, timeout=timeout)
+        done, pending = yield from asyncio.wait([deliver_task], loop=self._loop, return_when=asyncio.FIRST_EXCEPTION, timeout=timeout)
+        if pending:
+            #timeout occured before message received
+            deliver_task.cancel()
         if deliver_task.exception():
             raise deliver_task.exception()
         self.client_tasks.pop()

hbmqtt/mqtt/protocol/handler.py

@@ -454,7 +454,10 @@ class ProtocolHandler:
     def mqtt_deliver_next_message(self):
         if self.logger.isEnabledFor(logging.DEBUG):
             self.logger.debug("%d message(s) available for delivery" % self.session.delivered_message_queue.qsize())
-        message = yield from self.session.delivered_message_queue.get()
+        try:
+            message = yield from self.session.delivered_message_queue.get()
+        except asyncio.CancelledError:
+            message = None
         if self.logger.isEnabledFor(logging.DEBUG):
             self.logger.debug("Delivering message %s" % message)
         return message