Schema `OnChange` delegates not removable

Colyseus Unity client version: 0.14.7 (latest) Colyseus server version: 0.14.1 (not latest, but issue is client-side)

If you store a reference to a Schema object other than the root schema, later (after a schema patch?) attempting to remove a delegate from that reference’s OnChange event will fail silently.

See comments in the example client code below for more specifics on what’s going wrong. It looks like Colyseus is doing something to the OnChange references that’s breaking the ability to remove delegates.

Example server code:

export default class Phase extends Schema {
  @type('int32')
  public value: number;

  constructor() {
    super();
    this.value = 1;
  }
}

export default class GameState extends Schema {
  @type(Phase)
  public readonly phase: Phase;

  constructor() {
    super();
    this.phase = new Phase();
  }
}

export default class GameRoom extends Room<GameState> {

  // ...

  onCreate(options: any) {
    let gameState = new GameState();
    this.setState(gameState);

    this.clock.setInterval(() => {
      console.log('changing phase');
      this.state.phase.value++;
    }, 1000);
  }

}

Example client code:

class MyClass {
  private GameState gameState;
  private Phase phase;

  // Start by calling this only once.
  private void AddDelegate(GameState gameState) {
    this.gameState = gameState;
    this.phase = gameState.phase;

    this.gameState.phase.OnChange += MyCallback1;
    this.phase.OnChange += MyCallback2;
  }

  private void MyCallback1(List<DataChange> change) {
    Debug.Log("MyCallback1 called");

    // This unregisters the callback correctly.
    this.gameState.phase.OnChange -= MyCallback1;
  }

  private void MyCallback2(List<DataChange> change) {
    Debug.Log("MyCallback2 called");

    // This doesn't unregister the callback correctly. No error is thrown, and this callback keeps
    // getting called.
    this.phase.OnChange -= MyCallback2;
  }
}

[endel]

Interesting, thanks for reporting again @rnd256, I’m gonna have a look at this during this week!

[RaidelRoss]

I already found the solution, your comments were helpful, thank you

private void ClientAdd(string key, DataClientLobby data)
{
  var clientLobby = Instantiate(clientLobby_prefab);
  clientLobby.Init(data, key.Equals(lobby.SessionId));
  entities.Add(data, clientLobby);
  
  data.OnChange += OnChange;
  onStateChange?.Invoke();
}