Fix dispatcher on_socks5_tcp_data when transport is none

src/tribler/core/components/tunnel/community/dispatcher.py

@@ -93,9 +93,13 @@ async def on_socks5_tcp_data(self, tcp_connection, destination, request):
             self._logger.info('Failed to get HTTP response using tunnels: %s', e)
             return
 
+        transport = tcp_connection.transport
+        if not transport:
+            return
+
         if response:
-            tcp_connection.transport.write(response)
-        tcp_connection.transport.close()
+            transport.write(response)
+        transport.close()
 
     def select_circuit(self, connection, request):
         if request.destination[1] == CIRCUIT_ID_PORT:

src/tribler/core/components/tunnel/tests/test_dispatcher.py

@@ -94,6 +94,14 @@ async def test_on_socks_in_tcp(dispatcher):
     tcp_connection.transport.write.assert_called_once_with(b'test')
 
 
+async def test_on_socks5_tcp_data_with_transport_none(dispatcher):
+    tcp_connection = Mock(transport=None)
+    dispatcher.set_socks_servers([tcp_connection.socksserver])
+
+    dispatcher.tunnels.perform_http_request = Mock(return_value=succeed(b'test'))
+    await dispatcher.on_socks5_tcp_data(tcp_connection, ("0.0.0.0", 1024), b'')
+
+
 def test_circuit_dead(dispatcher, mock_circuit):
     """
     Test whether the correct peers are removed when a circuit breaks