NetworkObject gets duplicated on client

[DreadBoy]

Describe the bug
When spawning NetworkObject on server, it gets duplicated on client.

To Reproduce

1. Clone https://github.com/DreadBoy/mlapi-repro
2. Read README.md

Actual outcome
Unit is instantiated twice on client, there are 2 Unit(Clone) objects in scene.

Expected outcome
Unit should be instantiated twice.

Screenshots

Environment (please complete the following information):

• OS: Windows 10
• Unity Version: 2021.1.6f1
• MLAPI Version: 0.1.0
• MLAPI Commit: idk, I used this to install: https://docs-multiplayer.unity3d.com/docs/migration/install/index.html

[LukeStampfli]

Can you please explain how to reproduce the bug (maybe share some code how you are creating this Unit(Clone)) so that we can triage this before spending hours on figuring out what's wrong? Thanks.

[DreadBoy]

I included minimal repro case but I can also walk you through the code.

I used a feature where network manager would instantiate a player prefab for each connection. That player prefab is empty GameObject with this script attached:

public class Player : NetworkBehaviour
{
    public Unit unitPrefab;

    public override void NetworkStart()
    {
        if (!IsServer)
        {
            enabled = false;
            return;
        }

        var unit = Instantiate(unitPrefab);
        var networkObject = unit.GetComponent<NetworkObject>();
        if (!networkObject.IsSpawned)
            networkObject.Spawn();
    }
}

Unit is simple cube (menu Create -> 3D -> Cube) with another empty script.

As described in repro case's readme, run this project twice in separate editors, start server in 1st and client in 2nd. Cube will be duplicated on client.

This works (or rather breaks) also if you build the project and run server from .exe and client from editor.

[LukeStampfli]

Thanks a lot, this description allows us to triage and assign the right engineer to this etc. 👍

[NoelStephensUnity]

Hi DreadBpy,
First I noticed you are running two editors? Are you duplicating the folder or are you running two editors from the same folder?
(just need to know how you are doing this in order to better help you with this issue)

Regarding the duplicated Spawned Objects:
It looks like this could be a script associated with a player?
If so, is the associated GameObject a Prefab in the NetworkManager's NetworkPrefab list?
If so, is it marked as the PlayerPrefab and is the NetworkManager configured to auto spawn the players?

If you answered yes to all of the above questions, then:
Try to just remove all of the code in NetworkSpawn and run your test again.

If you answered no to any of the above questions, then could you describe a bit more what you are trying to accomplish? (i.e. wanting to spawn players yourself or the like)

[NoelStephensUnity]

@DreadBoy
Just following up to see if you have resolved your issue or if this issue is still outstanding.

[NoelStephensUnity]

@DreadBoy
Feel free to post here if you find that your issue is not resolved please feel free to respond at any time.