Update the messages callback to not mutate the protocol once created.

Author: allenporter

roborock/devices/local_channel.py

@@ -51,20 +51,26 @@ class LocalChannel(Channel):
     format most parsing to higher-level components.
     """
 
-    _protocol_cache: dict[str, LocalProtocolVersion] = {}
 
     def __init__(self, host: str, local_key: str):
         self._host = host
         self._transport: asyncio.Transport | None = None
         self._protocol: _LocalProtocol | None = None
         self._subscribers: CallbackList[RoborockMessage] = CallbackList(_LOGGER)
         self._is_connected = False
-        self._local_protocol_version: LocalProtocolVersion | None = self._protocol_cache.get(host)
+        self._local_protocol_version: LocalProtocolVersion | None = None
         self._update_encoder_decoder(
             LocalChannelParams(local_key=local_key, connect_nonce=get_next_int(10000, 32767), ack_nonce=None)
         )
 
-    def _update_encoder_decoder(self, params: LocalChannelParams):
+    def _update_encoder_decoder(self, params: LocalChannelParams) -> None:
+        """Update the encoder and decoder with new parameters.
+        
+        This is invoked once with an initial set of values used for protocol
+        negotiation. Once negotiation completes, it is updated again to set the
+        correct nonces for the follow up communications and updates the encoder
+        and decoder functions accordingly.
+        """
         self._params = params
         self._encoder = create_local_encoder(
             local_key=params.local_key, connect_nonce=params.connect_nonce, ack_nonce=params.ack_nonce
@@ -73,9 +79,7 @@ def _update_encoder_decoder(self, params: LocalChannelParams):
             local_key=params.local_key, connect_nonce=params.connect_nonce, ack_nonce=params.ack_nonce
         )
         # Callback to decode messages and dispatch to subscribers
-        self._data_received: Callable[[bytes], None] = decoder_callback(self._decoder, self._subscribers, _LOGGER)
-        if self._protocol:
-            self._protocol.messages_cb = self._data_received
+        self._dispatch = decoder_callback(self._decoder, self._subscribers, _LOGGER)
 
     async def _do_hello(self, local_protocol_version: LocalProtocolVersion) -> LocalChannelParams | None:
         """Perform the initial handshaking and return encoder params if successful."""
@@ -125,7 +129,6 @@ async def _hello(self):
             if params is not None:
                 self._local_protocol_version = version
                 self._update_encoder_decoder(params)
-                self._protocol_cache[self._host] = self._local_protocol_version
                 return
 
         raise RoborockException("Failed to connect to device with any known protocol")
@@ -169,6 +172,10 @@ async def connect(self) -> None:
             self.close()
             raise
 
+    def _data_received(self, data: bytes) -> None:
+        """Invoked when data is received on the stream."""
+        self._dispatch(data)
+
     def close(self) -> None:
         """Disconnect from the device."""
         if self._transport: