SyncList double items for the third client

[busaku]

General
Unity version: 6000.0.28f1
Fish-Networking version: 4.6.8R

Description
The third (and more) Client got one extra Item in SyncList

Replication
Use this script:

using System;
using FishNet.Object;
using FishNet.Object.Synchronizing;
using UnityEngine;

public class PlayerManager : NetworkBehaviour
{
    public static PlayerManager Instance { get; private set; }

    private readonly SyncList<PlayerStat> players = new();

    public static event Action<SyncList<PlayerStat>> OnPlayersChanged;

    private void Awake()
    {
        if (Instance != null && Instance != this)
        {
            Destroy(this);
            return;
        }

        Instance = this;

        players.OnChange += playersChange;
    }

    private void playersChange(SyncListOperation op, int index,
     PlayerStat oldItem, PlayerStat newItem, bool asServer)
    {
        Debug.Log($"[PlayerManager] Player list changed: {op} at index {index} Server: {asServer}");
        //OnPlayersChanged?.Invoke(players);

        // list debug 
        for (int i = 0; i < players.Count; i++)
        {
            Debug.Log($"Player {i}: {players[i].playerName} (ID: {players[i].connectionId})");
        }
    }

    [Server]
    public void RegisterPlayer(int connectionId, string playerName, string characterClass)
    {
        Debug.Log("Test");
        bool alreadyRegistered = false;
        foreach (var p in players)
        {
            if (p.connectionId == connectionId)
            {
                alreadyRegistered = true;
                break;
            }
        }

        if (!alreadyRegistered)
        {
            var playerStat = new PlayerStat
            {
                connectionId = connectionId,
                playerName = playerName,
            };
            players.Add(playerStat);
            Debug.Log($"[PlayerManager] Registered: {playerName} ({connectionId})");
        }
    }

    [Server]
    public void UnregisterPlayer(int connectionId)
    {
        int index = players.FindIndex(p => p.connectionId == connectionId);
        if (index >= 0)
        {
            var removed = players[index];
            Debug.Log($"[PlayerManager] Unregistered: {players[index].playerName} ({connectionId})");
            players.RemoveAt(index);
        }
    }
}

and than call this on you player-Prefab (spawned by FishNet):

    public override void OnStartServer()
    {
        base.OnStartServer();

        if (!IsServerInitialized) return; 

        // Temporärer Dummy-Name
        string name = $"Player_{Owner.ClientId}";
        string klass = "Default";

        PlayerManager.Instance?.RegisterPlayer(Owner.ClientId, name, klass);
    }

Result
All Clients, after the first, got an extra Item inside the SyncList (Copy of her own?).
Means: The Server and the First Client have this list after all clients are joined:

Player 2 got:
(ID 1 = Player2)

And Player 3 got:

I don't have an idea, why the clients just get a copy of the own PlayerStat.
And i don't know why it doesn't happend on the first Client or even the Server?

Thanks in advance :)

[busaku]

Oh, i forgot my PlayerStat, its currently just a placeholder:

public class PlayerStat
{
    public string playerName;
    public string characterClass;
    public int Level = 1;
    public int Health = 100;
    public int MaxHealth = 100;
    public int connectionId;
}

[FirstGearGames]

I was not able to replicate using Beta or Stable SyncTypes.

Attached is the test project I used. I made some very minor modifications to the scripts for tidy reasons.

objectNames are set based on your 'string name = $"Player_{Owner.ClientId}";', this is purely cosmetic.

I also added this

        //To prevent console spam and to make things more clear, only print if op code is complete, indicating all entries are added/modified.
        if (op != SyncListOperation.Complete)
            return;
        

MultipleSyncList_Report.zip

[busaku]

So, yes...
I imported your scene, and it just works fine.
But to be honest, I don't see any reason.

Anyway, it doesn’t seem to be a bug, thanks for your help!

[busaku]

ahh:
if i add the default fishnet Networkmanager Prefab to you scene, you will get the same bug!

[busaku]

Thats it:
Remove the "ObserverManager" from the default Prefab and it runs fine.
If you add the ObserverManager to your Networkmanager, you won't get the bug.
If you just disable the ObserverManager from default Prefab, the bug is still there.
If you add the default Prefab to your scene, you got the same bug.

[maxkratt]

I can confirm that simply adding the ObserverManager with a Scene Condition causes the issue to show itself.
Requesting that this be re-opened.