Unity-Technologies · EmandM · May 12, 2026
@@ -2,6 +2,8 @@
 using System.Collections.Generic;
 using System.Linq;
 using Unity.Collections;
+using Unity.Netcode.Logging;
+using UnityEditor;
 using UnityEngine;
 using UnityEngine.Serialization;
 
@@ -246,11 +248,19 @@ internal NetworkConfig Copy()
         /// runtime modifications to a property outside of the recommended range.
         /// For each property checked below, provide a brief description of the reason.
         /// </remarks>
-        internal void OnValidate()
+        internal void OnValidate(ContextualLogger log)
         {
             // Legacy NGO versions defaulted this value to 1 second that has since been determiend
             // any range less than 10 seconds can lead to dropped messages during scene events.
             SpawnTimeout = Mathf.Clamp(SpawnTimeout, MinSpawnTimeout, MaxSpawnTimeout);
+
+            var activeScene = UnityEngine.SceneManagement.SceneManager.GetActiveScene();
+
+            // If the scene is dirty and the asset database is not currently updating then we can validate the NetworkPrefabs
+            if (activeScene.isDirty && !EditorApplication.isUpdating)
+            {
+                Prefabs.Initialize(log);
+            }
         }
 
         /// <summary>
@@ -378,26 +388,14 @@ public bool CompareConfig(ulong hash)
             return hash == GetConfig();
         }
 
-        internal void InitializePrefabs()
+        internal void InitializePrefabs(ContextualLogger log)
         {
             if (HasOldPrefabList())
             {
                 MigrateOldNetworkPrefabsToNetworkPrefabsList();
             }
 
-            Prefabs.Initialize();
-        }
-
-        [NonSerialized]
-        private bool m_DidWarnOldPrefabList = false;
-
-        private void WarnOldPrefabList()
-        {
-            if (!m_DidWarnOldPrefabList)
-            {
-                Debug.LogWarning("Using Legacy Network Prefab List. Consider Migrating.");
-                m_DidWarnOldPrefabList = true;
-            }
+            Prefabs.Initialize(log);
         }
 
         /// <summary>

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using Unity.Netcode.Logging;
 using UnityEngine;
 
 namespace Unity.Netcode
@@ -146,24 +148,37 @@ public uint TargetPrefabGlobalObjectIdHash
         /// <returns>True if the NetworkPrefab is valid and ready for use, false otherwise</returns>
         public bool Validate(int index = -1)
         {
+            var log = new ContextualLogger();
+            return Validate(log, index);
+        }
+
+        internal bool Validate(ContextualLogger log, int index = -1)
+        {
+            using var logContext = log.AddDisposableInfo("Invalid prefab", Prefab?.name);
+
             NetworkObject networkObject;
             if (Override == NetworkPrefabOverride.None)
             {
                 if (Prefab == null)
                 {
-                    NetworkLog.LogWarning($"{nameof(NetworkPrefab)} cannot be null ({nameof(NetworkPrefab)} at index: {index})");
+                    log.Warning(new Context(LogLevel.Error, $"{nameof(NetworkPrefab)} cannot be null").AddInfo($"{nameof(NetworkPrefab)} at index", index));
                     return false;
                 }
 
                 networkObject = Prefab.GetComponent<NetworkObject>();
                 if (networkObject == null)
                 {
-                    if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
+                    log.Warning(new Context(LogLevel.Error, $"Prefab is missing a {nameof(NetworkObject)} component!").AddObject(Prefab));
+                    return false;
+                }
+
+                {
+                    var childNetworkObjects = new List<NetworkObject>();
+                    Prefab.GetComponentsInChildren(true, childNetworkObjects);
+                    if (childNetworkObjects.Count > 1) // total count = 1 root NetworkObject + n child NetworkObjects
                     {
-                        NetworkLog.LogWarning($"{NetworkPrefabHandler.PrefabDebugHelper(this)} is missing a {nameof(NetworkObject)} component (entry will be ignored).");
+                        log.Warning(new Context(LogLevel.Error, $"Prefab has child {nameof(NetworkObject)}(s) but they will not be spawned across the network (unsupported {nameof(NetworkPrefab)} setup)").AddObject(Prefab));
                     }
-
-                    return false;
                 }
 
                 return true;
@@ -176,14 +191,9 @@ public bool Validate(int index = -1)
                     {
                         if (SourceHashToOverride == 0)
                         {
-                            if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
-                            {
-                                NetworkLog.LogWarning($"{nameof(NetworkPrefab)} {nameof(SourceHashToOverride)} is zero (entry will be ignored).");
-                            }
-
+                            log.Warning(new Context(LogLevel.Error, $"{nameof(NetworkPrefab)} {nameof(SourceHashToOverride)} is zero!"));
                             return false;
                         }
-
                         break;
                     }
                 case NetworkPrefabOverride.Prefab:
@@ -197,20 +207,16 @@ public bool Validate(int index = -1)
                             {
                                 SourcePrefabToOverride = Prefab;
                             }
-                            else if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
+                            else
                             {
-                                NetworkLog.LogWarning($"{nameof(NetworkPrefab)} {nameof(SourcePrefabToOverride)} is null (entry will be ignored).");
+                                log.Warning(new Context(LogLevel.Error, $"{nameof(NetworkPrefab)} {nameof(SourcePrefabToOverride)} is null!"));
                                 return false;
                             }
                         }
 
                         if (!SourcePrefabToOverride.TryGetComponent(out networkObject))
                         {
-                            if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
-                            {
-                                NetworkLog.LogWarning($"{nameof(NetworkPrefab)} ({SourcePrefabToOverride.name}) is missing a {nameof(NetworkObject)} component (entry will be ignored).");
-                            }
-
+                            log.Warning(new Context(LogLevel.Error, $"{nameof(NetworkPrefab)} is missing a {nameof(NetworkObject)} component!").AddObject(SourcePrefabToOverride));
                             return false;
                         }
 
@@ -221,21 +227,18 @@ public bool Validate(int index = -1)
             // Validate target prefab override values next
             if (OverridingTargetPrefab == null)
             {
-                if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
-                {
-                    NetworkLog.LogWarning($"{nameof(NetworkPrefab)} {nameof(OverridingTargetPrefab)} is null!");
-                }
-
+                // Safe to create context early as this code is not in any hot path
+                var ctx = new Context(LogLevel.Error, $"{nameof(OverridingTargetPrefab)} is null! {nameof(NetworkPrefab)} entry will be removed and ignored.");
                 switch (Override)
                 {
                     case NetworkPrefabOverride.Hash:
                         {
-                            Debug.LogWarning($"{nameof(NetworkPrefab)} override entry {SourceHashToOverride} will be removed and ignored.");
+                            log.Warning(ctx.AddInfo(nameof(SourceHashToOverride), SourceHashToOverride));
                             break;
                         }
                     case NetworkPrefabOverride.Prefab:
                         {
-                            Debug.LogWarning($"{nameof(NetworkPrefab)} override entry ({SourcePrefabToOverride.name}) will be removed and ignored.");
+                            log.Warning(ctx.AddInfo(nameof(SourcePrefabToOverride), SourcePrefabToOverride.name));
                             break;
                         }
                 }

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
+using Unity.Netcode.Logging;
 using UnityEngine;
 
 namespace Unity.Netcode
@@ -50,9 +50,15 @@ public class NetworkPrefabs
         [NonSerialized]
         private List<NetworkPrefab> m_RuntimeAddedPrefabs = new List<NetworkPrefab>();
 
+        private ContextualLogger m_Log;
+
+        private bool m_Initialized;
+
+
         private void AddTriggeredByNetworkPrefabList(NetworkPrefab networkPrefab)
         {
-            if (AddPrefabRegistration(networkPrefab))
+            // We don't have to re-validate the prefab as the PrefabList will have validated before invoking this
+            if (AddPrefabRegistrationPreValidated(networkPrefab))
             {
                 // Don't add this to m_RuntimeAddedPrefabs
                 // This prefab is now in the PrefabList, so if we shutdown and initialize again, we'll pick it up from there.
@@ -79,6 +85,7 @@ private void RemoveTriggeredByNetworkPrefabList(NetworkPrefab networkPrefab)
         /// </summary>
         internal void Shutdown()
         {
+            m_Initialized = false;
             foreach (var list in NetworkPrefabsLists)
             {
                 list.OnAdd -= AddTriggeredByNetworkPrefabList;
@@ -93,27 +100,18 @@ internal void Shutdown()
         /// <param name="warnInvalid">When true, logs warnings about invalid prefabs that are removed during initialization</param>
         public void Initialize(bool warnInvalid = true)
         {
+            Initialize(m_Log ?? new ContextualLogger(), warnInvalid);
+        }
+
+        internal void Initialize(ContextualLogger log, bool warnInvalid = true)
+        {
+            m_Log = log;
             m_Prefabs.Clear();
             NetworkPrefabsLists.RemoveAll(x => x == null);
-            foreach (var list in NetworkPrefabsLists)
-            {
-                list.OnAdd += AddTriggeredByNetworkPrefabList;
-                list.OnRemove += RemoveTriggeredByNetworkPrefabList;
-            }
 
             NetworkPrefabOverrideLinks.Clear();
             OverrideToNetworkPrefab.Clear();
 
-            var prefabs = new List<NetworkPrefab>();
-
-            if (NetworkPrefabsLists.Count != 0)
-            {
-                foreach (var list in NetworkPrefabsLists)
-                {
-                    prefabs.AddRange(list.PrefabList);
-                }
-            }
-
             m_Prefabs = new List<NetworkPrefab>();
 
             List<NetworkPrefab> removeList = null;
@@ -122,15 +120,33 @@ public void Initialize(bool warnInvalid = true)
                 removeList = new List<NetworkPrefab>();
             }
 
-            foreach (var networkPrefab in prefabs)
+            foreach (var list in NetworkPrefabsLists)
             {
-                if (AddPrefabRegistration(networkPrefab))
+                if (list == null)
                 {
-                    m_Prefabs.Add(networkPrefab);
+                    continue;
                 }
-                else
+                // Validate will remove any invalid items from the list
+                list.BuildLogger();
+
+                list.OnAdd += AddTriggeredByNetworkPrefabList;
+                list.OnRemove += RemoveTriggeredByNetworkPrefabList;
+
+                foreach (var networkPrefab in list.List)
                 {
-                    removeList?.Add(networkPrefab);
+                    if (networkPrefab == null)
+                    {
+                        continue;
+                    }
+
+                    if (networkPrefab.Validate(list.Log) && AddPrefabRegistrationPreValidated(networkPrefab))
+                    {
+                        m_Prefabs.Add(networkPrefab);
+                    }
+                    else
+                    {
+                        removeList?.Add(networkPrefab);
+                    }
                 }
             }
 
@@ -149,13 +165,10 @@ public void Initialize(bool warnInvalid = true)
             // Clear out anything that is invalid or not used
             if (removeList?.Count > 0)
             {
-                if (NetworkLog.CurrentLogLevel <= LogLevel.Error)
-                {
-                    var sb = new StringBuilder("Removing invalid prefabs from Network Prefab registration: ");
-                    sb.AppendJoin(", ", removeList);
-                    NetworkLog.LogWarning(sb.ToString());
-                }
+                log.Warning(new Context(LogLevel.Error, "Removing invalid prefabs from Network Prefab registration"));
             }
+
+            m_Initialized = true;
         }
 
         /// <summary>
@@ -171,6 +184,12 @@ public void Initialize(bool warnInvalid = true)
         /// </remarks>
         public bool Add(NetworkPrefab networkPrefab)
         {
+            if (!m_Initialized)
+            {
+                m_RuntimeAddedPrefabs.Add(networkPrefab);
+                return true;
+            }
+
             if (AddPrefabRegistration(networkPrefab))
             {
                 m_Prefabs.Add(networkPrefab);
@@ -287,43 +306,40 @@ private bool AddPrefabRegistration(NetworkPrefab networkPrefab)
                 return false;
             }
             // Safeguard validation check since this method is called from outside of NetworkConfig and we can't control what's passed in.
-            if (!networkPrefab.Validate())
+            if (!networkPrefab.Validate(m_Log))
             {
                 return false;
             }
+            return AddPrefabRegistrationPreValidated(networkPrefab);
+        }
 
+        private bool AddPrefabRegistrationPreValidated(NetworkPrefab networkPrefab)
+        {
             uint source = networkPrefab.SourcePrefabGlobalObjectIdHash;
             uint target = networkPrefab.TargetPrefabGlobalObjectIdHash;
 
             // Make sure the prefab isn't already registered.
-            if (NetworkPrefabOverrideLinks.ContainsKey(source))
+            if (NetworkPrefabOverrideLinks.TryGetValue(source, out var otherPrefab))
             {
-                var networkObject = networkPrefab.Prefab.GetComponent<NetworkObject>();
-
                 // This should never happen, but in the case it somehow does log an error and remove the duplicate entry
-                Debug.LogError($"{nameof(NetworkPrefab)} ({networkObject.name}) has a duplicate {nameof(NetworkObject.GlobalObjectIdHash)} source entry value of: {source}!");
+                m_Log.Error(new Context(LogLevel.Error, $"{nameof(NetworkPrefab)} has a matching {nameof(NetworkObject.GlobalObjectIdHash)} with another object. This should not happen!").AddInfo(nameof(NetworkObject.GlobalObjectIdHash), source).AddInfo("Duplicated Object", otherPrefab.Prefab.name).AddObject(networkPrefab.Prefab));
                 return false;
             }
 
-            // If we don't have an override configured, registration is simple!
-            if (networkPrefab.Override == NetworkPrefabOverride.None)
-            {
-                NetworkPrefabOverrideLinks.Add(source, networkPrefab);
-                return true;
-            }
-
             switch (networkPrefab.Override)
             {
+                case NetworkPrefabOverride.None:
+                    {
+                        NetworkPrefabOverrideLinks.Add(source, networkPrefab);
+                        break;
+                    }
                 case NetworkPrefabOverride.Prefab:
                 case NetworkPrefabOverride.Hash:
                     {
                         NetworkPrefabOverrideLinks.Add(source, networkPrefab);
-                        if (!OverrideToNetworkPrefab.ContainsKey(target))
-                        {
-                            OverrideToNetworkPrefab.Add(target, source);
-                        }
+                        OverrideToNetworkPrefab.TryAdd(target, source);
+                        break;
                     }
-                    break;
             }
 
             return true;