fix

Wrapping some unified stuff in defines.

Author: NoelStephensUnity

com.unity.netcode.gameobjects/Runtime/Core/NetworkManager.cs

@@ -1341,9 +1341,8 @@ private bool CanStart(StartType type)
             return true;
         }
 
-        public NetcodeWorld NetcodeWorld { get; internal set; }
-
 #if UNIFIED_NETCODE
+        public NetcodeWorld NetcodeWorld { get; internal set; }
         private System.Collections.IEnumerator WaitForHybridPrefabRegistration(StartType startType)
         {
             if (this == Singleton)

com.unity.netcode.gameobjects/Tests/Runtime/TestHelpers/NetcodeIntegrationTest.cs

@@ -6,7 +6,9 @@
 using System.Runtime.CompilerServices;
 using System.Text;
 using NUnit.Framework;
+#if UNIFIED_NETCODE
 using Unity.NetCode;
+#endif
 using Unity.Netcode.RuntimeTests;
 using Unity.Netcode.Transports.UTP;
 using UnityEngine;
@@ -1758,6 +1760,7 @@ protected void DestroySceneNetworkObjects()
 
                 if (CanDestroyNetworkObject(networkObject))
                 {
+#if UNIFIED_NETCODE
                     // Handle removing the prefab reference and destroying it
                     // and then destroying the ghostAdapter prior to destroying
                     // a hybrid prefab. 
@@ -1770,7 +1773,7 @@ protected void DestroySceneNetworkObjects()
                         Object.Destroy(prefabReference);
                         Object.Destroy(ghostAdapter);
                     }
-
+#endif
                     // Destroy the GameObject that holds the NetworkObject component
                     Object.DestroyImmediate(networkObject.gameObject);
                 }
@@ -2387,7 +2390,14 @@ protected void SpawnObjectInstance(NetworkObject networkObjectToSpawn, NetworkMa
         private GameObject SpawnObject(NetworkObject prefabNetworkObject, NetworkManager owner, bool destroyWithScene = false, bool isPlayerObject = false)
         {
             Assert.IsTrue(prefabNetworkObject.GlobalObjectIdHash > 0, $"{nameof(GameObject)} {prefabNetworkObject.name} has a {nameof(NetworkObject.GlobalObjectIdHash)} value of 0! Make sure to make it a valid prefab before trying to spawn!");
-            NetCode.Netcode.Instance.m_ActiveWorld = owner.NetcodeWorld;
+#if UNIFIED_NETCODE
+            // TODO-FixMe: NetCode.Netcode.Instance is a singleton and might cause issues
+            // assigning this.
+            if (prefabNetworkObject.HasGhost)
+            {
+                NetCode.Netcode.Instance.m_ActiveWorld = owner.NetcodeWorld;
+            }
+#endif            
             var newInstance = Object.Instantiate(prefabNetworkObject.gameObject);
             var networkObjectToSpawn = newInstance.GetComponent<NetworkObject>();
             SpawnObjectInstance(networkObjectToSpawn, owner, destroyWithScene, isPlayerObject);