fix: NetworkVariable warnings on player spawns [MTT-7161] (Unity-Technologies#870)

* netvar instantiation pre-spawn

* changelog addition

Author: fernando-cortez

Assets/Scripts/Gameplay/GameState/ServerBossRoomState.cs

@@ -204,13 +204,13 @@ void SpawnPlayer(ulong clientId, bool lateJoin)
                 }
             }
 
-            networkAvatarGuidState.AvatarGuid.Value =
-                persistentPlayer.NetworkAvatarGuidState.AvatarGuid.Value;
+            // instantiate new NetworkVariables with a default value to ensure they're ready for use on OnNetworkSpawn
+            networkAvatarGuidState.AvatarGuid = new NetworkVariable<NetworkGuid>(persistentPlayer.NetworkAvatarGuidState.AvatarGuid.Value);
 
             // pass name from persistent player to avatar
             if (newPlayer.TryGetComponent(out NetworkNameState networkNameState))
             {
-                networkNameState.Name.Value = persistentPlayer.NetworkNameState.Name.Value;
+                networkNameState.Name = new NetworkVariable<FixedPlayerName>(persistentPlayer.NetworkNameState.Name.Value);
             }
 
             // spawn players characters with destroyWithScene = true

CHANGELOG.md

@@ -6,6 +6,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 Additional documentation and release notes are available at [Multiplayer Documentation](https://docs-multiplayer.unity3d.com).
 
+## [unreleased] - yyyy-mm-dd
+
+### Fixed
+* Fixed NetworkVariable warnings that would be logged when a player was spawned (#863) For a player, certain NetworkVariable values were previously modified before the player's NetworkObject was spawned, resulting in warnings. Now, the NetworkVariable itself is instantiated on the server pre-spawn, such that it is instantiated with the new default value, ensuring the new default value is ready to be read on subsequent OnNetworkSpawn methods for said NetworkObject.
+
 ## [2.3.0] - 2023-09-07
 
 ### Changed