LateInitializationError: Field 'messageStream' has not been initialized.

[stijn1989]

When you have a Dart program which starts and connects to a MQTT broker. But the broker is offline, so you start the autoConnect proces.

try {
  await mqtt.connect();
  mqtt.sub();
} catch (e) {
  mqtt.client.doAutoReconnect();
}

When the MQTT broker is back online, it connects. But an exception is thrown because the messageStream isn't initialized. The late property is only set in the connect() method and should also be set in the connectAuto().

The mqtt_browser_ws_connection.dart is correct. The mqtt_server_*_connection.dart not.

Also the event handler onAutoReconnected isn't set and by this never called.

client.onAutoReconnected = () {
  if(client.subscriptionsManager!.subscriptions.isEmpty) {
    //initialize the subscriptions
  }
};

[shamblett]

I'm not sure why you need to recreate readWrapper and messageStream in the connectAuto method, these are created in the connect method which you must call first and as far as I can see never subsequently destroyed. Your use case seems a little odd, you can't invoke autoConnect until connect has worked. Another way to do this is to move the setting of readWrapper and messageStream to the top of the connect method, i.e. they are in place before we start the socket connect, not after so they should persist from then on.

[stijn1989]

The objects are created when the socket has a connection. When there is no successfull connection, these objects aren't created. Moving them up, is a perfect solution. Why not make those fields final and initialised?

I invoke the doAutoConnect when the connect() fails. So the code is trying to attempt to connect. The event handlers are used to give information back to the logs.

I'm creating a program that needs the MQTT broker to work. And it should solve it's connection without user interaction.

[shamblett]

I see what you are saying, yes we could make them final and initialised. OK i understand what you are trying to do now.
Do you want to do the update or do you want me to do it?

[stijn1989]

I can do it tonight. I revert the commit and make those fields final and remove them in the connect and autoConnect methods. ok?

[shamblett]

Yep, sounds good to me, thanks.

[shamblett]

Package re published now at version 3.1.2