Fixes for MQTT client

- Fix setting connect flags related to LWT
- Display debug message when changing subscription QOS
- Replace max QOS argument

src/Networking/MQTT/MqttClient.cpp

@@ -385,27 +385,34 @@ void MqttClient::ConnectionLost() noexcept
 			}
 		}
 
+		uint8_t flags = 0;
+
 		switch (qos)
 		{
 		case 1:
-			client->connectFlags |= MQTT_CONNECT_WILL_QOS_1;
+			flags |= MQTT_CONNECT_WILL_QOS_1;
 			break;
 
 		case 2:
-			client->connectFlags |= MQTT_CONNECT_WILL_QOS_2;
+			flags |= MQTT_CONNECT_WILL_QOS_2;
 			break;
 
 		case 0:
 		default:
-			client->connectFlags |= MQTT_CONNECT_WILL_QOS_0;
+			flags |= MQTT_CONNECT_WILL_QOS_0;
 			break;
 		}
 
 		if (retain)
 		{
-			client->connectFlags |= MQTT_CONNECT_WILL_RETAIN;
+			flags |= MQTT_CONNECT_WILL_RETAIN;
 		}
 
+		// Bit 3, 4 for QOS and bit 5 for retain. Make sure in sync with definition
+		// in MQTTConnectFlags.
+		uint8_t mask = (0x03 << 3) | 32u;
+		client->connectFlags = (client->connectFlags & ~mask) | (flags & mask);
+
 		if (reprap.Debug(Module::Webserver))
 		{
 			debugPrintf("Set will message '%s' with topic '%s', QOS=%d, retain = %s\n",
@@ -419,7 +426,7 @@ void MqttClient::ConnectionLost() noexcept
 
 		// Check the max QOS first
 		int qos = 0;
-		if (gb.Seen('M'))
+		if (gb.Seen('O'))
 		{
 			qos = gb.GetIValue();
 			if (qos < 0 || qos > 2)
@@ -443,6 +450,11 @@ void MqttClient::ConnectionLost() noexcept
 		{
 			// Just overwrite the existing QOS
 			sub->qos = qos;
+
+			if (reprap.Debug(Module::Webserver))
+			{
+				debugPrintf("Subscription topic '%s' max QOS changed to %d \n", param.c_str(), qos);
+			}
 		}
 		else
 		{