Clean up Channel.__del__ logic

src/python/grpcio/grpc/_channel.py

@@ -966,11 +966,6 @@ def _poll_connectivity(state, channel, initial_try_to_connect):
                         _spawn_delivery(state, callbacks)
 
 
-def _moot(state):
-    with state.lock:
-        del state.callbacks_and_connectivities[:]
-
-
 def _subscribe(state, callback, try_to_connect):
     with state.lock:
         if not state.callbacks_and_connectivities and not state.polling:
@@ -1000,11 +995,6 @@ def _unsubscribe(state, callback):
                 break
 
 
-def _unsubscribe_all(state):
-    with state.lock:
-        del state.callbacks_and_connectivities[:]
-
-
 def _augment_options(base_options, compression):
     compression_option = _compression.create_channel_option(compression)
     return tuple(base_options) + compression_option + ((
@@ -1071,16 +1061,21 @@ class Channel(grpc.Channel):
             self._channel, _channel_managed_call_management(self._call_state),
             _common.encode(method), request_serializer, response_deserializer)
 
+    def _unsubscribe_all(self):
+        state = self._connectivity_state
+        if state:
+            with state.lock:
+                del state.callbacks_and_connectivities[:]
+
     def _close(self):
-        _unsubscribe_all(self._connectivity_state)
+        self._unsubscribe_all()
         self._channel.close(cygrpc.StatusCode.cancelled, 'Channel closed!')
         cygrpc.fork_unregister_channel(self)
-        _moot(self._connectivity_state)
 
     def _close_on_fork(self):
+        self._unsubscribe_all()
         self._channel.close_on_fork(cygrpc.StatusCode.cancelled,
                                     'Channel closed due to fork')
-        _moot(self._connectivity_state)
 
     def __enter__(self):
         return self
@@ -1102,7 +1097,9 @@ class Channel(grpc.Channel):
         # for as long as they are in use and to close them after using them,
         # then deletion of this grpc._channel.Channel instance can be made to
         # effect closure of the underlying cygrpc.Channel instance.
-        # This prevent the failed-at-initializing object removal from failing.
-        # Though the __init__ failed, the removal will still trigger __del__.
-        if _moot is not None and hasattr(self, '_connectivity_state'):
-            _moot(self._connectivity_state)
+        try:
+            self._unsubscribe_all()
+        except:
+            # Exceptions in __del__ are ignored by Python anyway, but they can
+            # keep spamming logs.  Just silence them.
+            pass