NetworkList - UnityException: EditorPrefsGetInt is not allowed to be called

Describe the bug

UnityException: EditorPrefsGetInt is not allowed to be called from a MonoBehaviour constructor (or instance field initializer), call it in Awake or Start instead. Called from MonoBehaviour 'Bag' on game object 'Player'.
See "Script Serialization" page in the Unity Manual for further details.
Unity.Collections.NativeLeakDetection.Initialize () (at /Users/bokken/buildslave/unity/build/Runtime/Export/NativeArray/DisposeSentinel.cs:28)
Unity.Collections.NativeLeakDetection.get_Mode () (at /Users/bokken/buildslave/unity/build/Runtime/Export/NativeArray/DisposeSentinel.cs:41)
Unity.Collections.LowLevel.Unsafe.DisposeSentinel.CreateInternal (Unity.Collections.LowLevel.Unsafe.DisposeSentinel& sentinel, System.Int32 callSiteStackDepth) (at /Users/bokken/buildslave/unity/build/Runtime/Export/NativeArray/DisposeSentinel.cs:107)
Unity.Collections.LowLevel.Unsafe.DisposeSentinel.Create (Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle& safety, Unity.Collections.LowLevel.Unsafe.DisposeSentinel& sentinel, System.Int32 callSiteStackDepth, Unity.Collections.Allocator allocator) (at /Users/bokken/buildslave/unity/build/Runtime/Export/NativeArray/DisposeSentinel.cs:101)
Unity.Collections.NativeList`1[T].Initialize[U] (System.Int32 initialCapacity, U& allocator, System.Int32 disposeSentinelStackDepth) (at Library/PackageCache/com.unity.collections@1.0.0-pre.5/Unity.Collections/NativeList.cs:141)
Unity.Collections.NativeList`1[T]..ctor (System.Int32 initialCapacity, Unity.Collections.AllocatorManager+AllocatorHandle allocator, System.Int32 disposeSentinelStackDepth) (at Library/PackageCache/com.unity.collections@1.0.0-pre.5/Unity.Collections/NativeList.cs:176)
Unity.Collections.NativeList`1[T]..ctor (System.Int32 initialCapacity, Unity.Collections.AllocatorManager+AllocatorHandle allocator) (at Library/PackageCache/com.unity.collections@1.0.0-pre.5/Unity.Collections/NativeList.cs:120)
Unity.Netcode.NetworkList`1[T]..ctor (System.Collections.Generic.IEnumerable`1[T] values) (at Library/PackageCache/com.unity.netcode.gameobjects@1.0.0-pre.2/Runtime/NetworkVariable/Collections/NetworkList.cs:13)
Bag.PostNetworkVariableWrite () (at Assets/Scripts/Resources/Bag.cs:8)

To Reproduce Steps to reproduce the behavior:

1. Use public NetworkList<Item> items { get; } = new NetworkList<Item>(new List<Item>()); as class member
2. Open Unity Editor
3. See error

Actual outcome No error

Expected outcome N/A

Screenshots

Environment (please complete the following information):

• OS: macOS
• Unity Version: 2021.1.24f1
• Netcode Version: 1.0.0-pre.2
• Netcode Commit: https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/commit/bcef5b992c5414707ff48c95a48a113fd0e09ad3

Additional context N/A

[mattwalsh-unity]

There is a straightforward workaround, namely, to move the instantiation into your Awake function.

[aefnor]

@ashwinimurt ashwinimurt why is this a won’t fix? Your docs are literally broken

using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using Unity.Netcode;
using UnityEngine;
using System;


public struct PlayerData : INetworkSerializable, IEquatable<PlayerData> {
    public FixedString512Bytes playerName;
    public ulong clientId;
    
    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref playerName);
        serializer.SerializeValue(ref clientId);
    }
    public bool Equals(PlayerData other)
    {
        return playerName == other.playerName && clientId.Equals(other.clientId);
    }
}
public class TeamManagerNetwork : NetworkBehaviour
{
    public NetworkList<PlayerData> playerData;

    // Use this method to add a new PlayerData to the list
    public void AddPlayerData(PlayerData data)
    {
        playerData.Add(data);
    }

    // Use this method to remove a PlayerData from the list
    public void RemovePlayerData(PlayerData data)
    {
        playerData.Remove(data);
    }
    void Awake () {
        playerData = new NetworkList<PlayerData>();
    }

    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        
    }
}

Even following the advice to move the instantiation to Awake() I still have issues.

Link from Unity Docs - https://docs-multiplayer.unity3d.com/netcode/current/basics/networkvariable/index.html#synchronizing-complex-types-example

{
    // ^^^^^^^ including all code from previous example ^^^^^^^

    // The weapon booster currently applied to a player
    private NetworkVariable<WeaponBooster> PlayerWeaponBooster = new NetworkVariable<WeaponBooster>();

    /// <summary>
    /// A list of team members active "area weapon boosters" that can be applied if the local player
    /// is within their range.
    /// </summary>
    private NetworkList<AreaWeaponBooster> TeamAreaWeaponBoosters;

    void Awake()
    {
        //NetworkList can't be initialized at declaration time like NetworkVariable. It must be initialized in Awake instead.
        TeamAreaWeaponBoosters = new NetworkList<AreaWeaponBooster>(); 
    }

    void Start()
    {
        /*At this point, the object hasn't been network spawned yet, so you're not allowed to edit network variables! */
        //list.Add(new AreaWeaponBooster());
    }

    void Update()
    {
        //This is just an example that shows how to add an element to the list after its initialization:
        if (!IsServer) { return; } //remember: only the server can edit the list
        if (Input.GetKeyUp(KeyCode.UpArrow)) 
        {
            TeamAreaWeaponBoosters.Add(new AreaWeaponBooster()));
        }
    }

    public override void OnNetworkSpawn()
    {
        base.OnNetworkSpawn();
        if (IsClient)
        {
            TeamAreaWeaponBoosters.OnListChanged += OnClientListChanged;
        }
        if (IsServer)
        {
            TeamAreaWeaponBoosters.OnListChanged += OnServerListChanged;
            TeamAreaWeaponBoosters.Add(new AreaWeaponBooster()); //if you want to initialize the list with some default values, this is a good time to do so.
        }
    }

    void OnServerListChanged(NetworkListEvent<AreaWeaponBooster> changeEvent)
    {
        Debug.Log($"[S] The list changed and now has {TeamAreaWeaponBoosters.Count} elements");
    }

    void OnClientListChanged(NetworkListEvent<AreaWeaponBooster> changeEvent)
    {
        Debug.Log($"[C] The list changed and now has {TeamAreaWeaponBoosters.Count} elements");
    }
}