Pre-existing NetworkObject are not spawned after NetworkManager.StartHost()

[acavailhez]

Description

Hi!
With version 2.13.0, NetworkObject present in the scene before NetworkManager.StartHost() are never spawned.
OnNetworkSpawn() is never called on the object, and all properties like IsSpawned, IsServer, etc are never instantiated.

On version 2.12.0, OnNetworkSpawn() is called correctly.

Reproduce Steps

1. Add a GameObject with a NetworkObject
2. A a NetworkManager and start a local server
3. NetworkObject is never spawned

Actual Outcome

OnNetworkSpawn() is never called on pre-existing NetworkObjects

Expected Outcome

OnNetworkSpawn() is called on pre-existing NetworkObjects

Environment

• OS: any
• Unity Version: 6000.3.11f1
• Netcode Version: 2.13.0
• Netcode Topology: Distributed Authority

[NoelStephensUnity]

@acavailhez
A few questions about your project as I am trying to replicate this issue.

• Do you have scene management enabled or disabled?
• Are you starting a server using the distributed authority network topology (your issue filed says this is what you are using).

Using distributed authority and client-server:

• With scene management enabled I cannot reproduce the issue.
• With scene management disabled, (making sure the in-scene placed is a network prefab instance and that it is included in your network prefab list) I cannot reproduce the issue.

If you are starting the server using the distributed authority network topology it will log an error and shutdown the NetworkManager:

Which would indeed not invoke the OnNetworkSpawn at that point.

Otherwise, there has to be some additional piece of information I am missing other than just adding a new GameObject to a scene and then adding a NetworkObject component.

Any additional details would be useful.

For reference purposes, here is the replication project I am using:
InSceneReplication-4072.zip

Feel free to modify/adjust this project if you can replicate the issue using it. When compressing (to post it here) only include the same folders as are in this zip file (i.e. Assets, Packages, ProjectSettings) to keep the file size super-small.

[acavailhez]

Hi @NoelStephensUnity!

OK I dug a little more and found that calling DontDestroyOnLoad() in Awake() triggers the bug.

The simplest setup I found to reproduce:

• A NetworkManager set with UnityTransport
• A NetworkObject

On the NetworkObject add:

public class TestNetworkObject : NetworkBehaviour
    {
        private void Awake()
        {
            DontDestroyOnLoad(gameObject);
        }

        public override void OnNetworkSpawn()
        {
            Debug.Log("Spawned");
        }
    }

On the NetworkManager add:

public class TestNetworkManager : MonoBehaviour
    {
        private void Start()
        {
            var networkManager = NetworkManager.Singleton;
            var unityTransport = networkManager.GetComponent<UnityTransport>();

            // Start local server
            unityTransport.UseWebSockets = false;
            unityTransport.SetConnectionData("0.0.0.0", 7777);
            networkManager!.NetworkConfig.NetworkTransport = unityTransport;
            networkManager.StartHost();

            Debug.Log("Host started");
        }
    }

On 2.13.0, "Host started" is logged but not "Spawned"

I also observed that:

• reverting to 2.12.0 triggers "Spawned"
• moving DontDestroyOnLoad in Start() (instead of Awake()) triggers "Spawned"
• scene management or topology doesn't seem to have any effect on the outcome

[NoelStephensUnity]

@acavailhez
This very likely is fixed in #4086 and/or #4073 which will be in the coming update.
If you want to verify one of these two PRs resolves the issue for your project, you can temporarily replace your manifest.json entry for com.unity.netcode.gameobjects with this:

"com.unity.netcode.gameobjects": "https://github.com/Unity-Technologies/com.unity.netcode.gameobjects.git?path=com.unity.netcode.gameobjects#develop-2.0.0",

If that does resolve your issue, then you can use that as a temporary resolution until the coming update.

[michalChrobot]

We released NGOv2.13.1 and this should resolve this issue (as it includes the PRs that Noel mentioned). I will close this issue but feel free to reopen if you still experience some bugs