[BUG] player.WaitForState() crashes when set for 2 or more players

[tulayha]

What happened?

Using player.WaitForState() causes errors when used for more than 1 player at a time.
Potential issue with static assignment for callback which gets overwritten internally on unity side (single static assignment).

Version

1.5.4

What is your environment?

Unity editor: 2022.3.62f3
WebGL build

Link to original discussion

No response

Relevant log output

[momintlh]

Seems to be failing at dynCall definitely something with the callback (might be incorrect marshalling)

[tulayha]

One issue is the callback handling in the following snippet.

      private static Action<string> onSetState;

      public void WaitForState(string stateKey, Action<string> onStateSetCallback = null)
      {
          onSetState = onStateSetCallback;
          _interop.WaitForPlayerStateWrapper(_id, stateKey, InvokeKickCallBack);
      }


      [MonoPInvokeCallback(typeof(Action<string>))]
      private static void InvokeKickCallBack(string data)
      {
          onSetState?.Invoke(data);
      }

In case of multiple waitForStates on different players (regardless of keys), the static action is overridden by the last wait set. All prior callbacks are essentially discarded internally and the last is retriggered each time InvokeKickCallBack (incorrect name but usage is correct) is invoked.
The current crashing is occurring when the game side callback method is processing, potentially due retriggering for one player again.

Example game code:

  player.WaitForState("pos", response =>
  {
     Debug.Log($"Player {player.id} position state received: {response}");
     var pos = player.GetState<Vector3>("pos");
     Debug.Log($"Spawning player {player.id} at position: {pos}");
     SetupPlayerEntity(player, pos, false);
     Debug.Log($"Player {player.id} joined.");
  });

Logs: