Handle unexpected errors while reconnecting (#119)

When we reconnect we are doing an explicit disconnect, this can fail and if
we don't handle possible exceptions we won't reconnect (even when it's
possible to do so)

A way to reproduce this easily is killing the connection with `ss -K`
(linux only)

gmqtt/client.py

@@ -194,7 +194,10 @@ async def reconnect(self, delay=False):
             return
         # stopping auto-reconnects during reconnect procedure is important, better do not touch :(
         self._temporatily_stop_reconnect()
-        await self._disconnect()
+        try:
+            await self._disconnect()
+        except:
+            logger.info('[RECONNECT] ignored error while disconnecting, trying to reconnect anyway')
         if delay:
             await asyncio.sleep(self._config['reconnect_delay'])
         try:

tests/test_mqtt5.py

@@ -1,6 +1,7 @@
 import asyncio
 import os
 import time
+from unittest import mock
 
 import pytest
 
@@ -462,3 +463,22 @@ async def test_basic_ssl(init_clients):
     aclient.publish(TOPICS[0], b"qos 2", 2)
     await asyncio.sleep(1)
     assert len(callback2.messages) == 3
+
+
+@pytest.mark.asyncio
+async def test_reconnection_with_failure(init_clients):
+    aclient, callback, bclient, callback2 = init_clients
+    aclient.set_config({'reconnect_retries': -1, 'reconnect_delay': 0})
+    await aclient.connect(host=host, port=port)
+    await bclient.connect(host=host, port=port)
+
+    bclient.subscribe(TOPICS[0])
+
+    with mock.patch.object(aclient, '_disconnect') as disconnect_mock:
+        disconnect_mock.side_effect = ConnectionAbortedError("error")
+        await aclient.reconnect()
+
+    # Check aclient is still working after reconnection
+    aclient.publish(TOPICS[0], b"test")
+    await asyncio.sleep(1)
+    assert len(callback2.messages) == 1