fix: spawn disabled in scene placed and network prefab registration (#4093)

* fix

- Issue where disabled in-scene placed NetworkObjects could not be spawned after starting a session.
- Issue where users are allowed to spawn a NetworkObject with a GlobalObjectIdHash value of 0 (zero).

* update

NetworkAnimator not pointing to an animator within awake now just logs a warning as opposed to an error.

* test

Updating tests based on the fixes applied to this branch.
A large portion is related to some integration tests trying to spawn NetworkObjects with a GlobalObjectIdHash value of zero(0).

* update

Style and providing internal write access to the prefabs list.

* test

Potentially last iteration on fixing/updating integration tests.

* test - fix

Using the fixed version of NetworkPrefabHandlerSpawnAndSynchronizeTests.
Fixing some issues with prefab and handler creation.

* style

Fixing formatting issues.

* style

Fixing some standards formatting related issues.

* style

removing trailing spaces.

* style

Super weird one... but using ? as opposed to an if null check.

* style

Removing commented out code that is no longer needed/used.

* update

Committing suggested changes.

Co-authored-by: Emma <emma.mcmillan@unity3d.com>

* update

Applying changes based on review discussion.

* update

Making adjustments based on review discussion.

* style

Removing field that is no longer valid.
Moving Awake higher in NetworkObject as it has become wedged in the middle of the code.

* update

Adding change log entries.

* update

Inverting logic (oops)

* doc

Updating NetworkObject documentation and in-scene placed documentation.

* Update documentation for the two types of NetworkObjects

Clarified the categories of NetworkObjects and their requirements. Added details for dynamically instantiated and in-scene placed NetworkObjects.

* style

White spaces!

* Apply suggestions from code review

Co-authored-by: Amy Reeve <amy.reeve@unity3d.com>

---------

Co-authored-by: Emma <emma.mcmillan@unity3d.com>
Co-authored-by: Amy Reeve <amy.reeve@unity3d.com>

Author: 3 people

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -14,6 +14,8 @@ Additional documentation and release notes are available at [Multiplayer Documen
 ### Changed
 
 
+
+
 ### Deprecated
 
 
@@ -22,6 +24,10 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Issue with not being able to spawn initially disabled in-scene placed objects. (#4093)
+- Issue with pre-instantiated network prefab instances being marked as in-scene placed. Now pre-instantiated network prefabs are dynamically spawned. (#4093)
+- Issue where a user could spawn runtime created `NetworkObject` that has a GlobalObjectIdHash of zero. These are not valid instances and will no longer be allowed to spawn. (#4093)
+
 
 ### Security
 

com.unity.netcode.gameobjects/Documentation~/basics/scenemanagement/inscene-placed-networkobjects.md

@@ -184,9 +184,13 @@ public class MyInSceneNetworkObjectBehaviour : NetworkBehaviour
 > [!NOTE]
 > You only need to enable the NetworkObject on the server-side to be able to respawn it. Netcode for GameObjects only enables a disabled in-scene placed NetworkObject on the client-side if the server-side spawns it. This **does not** apply to dynamically spawned `NetworkObjects`. Refer to [the object pooling page](../../advanced-topics/object-pooling.md) for an example of recycling dynamically spawned NetworkObjects.
 
+### Pre-disabled in-scene placed NetworkObjects
+
+To initialize an in-scene placed NetworkObject in a disabled state and spawn it later, set its GameObject to inactive in the Editor while the respective scene is open. Once a networked session begins, you can re-enable and spawn it at any time.
+
 ### Setting an in-scene placed NetworkObject to a despawned state when instantiating
 
-Since in-scene placed NetworkObjects are automatically spawned when their respective scene has finished loading during a network session, you might run into the scenario where you want it to start in a despawned state until a certain condition has been met. To do this, you need to add some additional code in the `OnNetworkSpawn` part of your NetworkBehaviour component:
+To programmatically disable an in-scene placed NetworkObject, add some additional code in the `OnNetworkSpawn` part of a NetworkBehaviour component:
 
 ```csharp
 using UnityEngine;

com.unity.netcode.gameobjects/Documentation~/components/core/networkobject.md

@@ -19,6 +19,32 @@ When spawning a NetworkObject, the `NetworkObject.GlobalObjectIdHash` value init
 
 You can use [NetworkBehaviours](networkbehaviour.md) to add your own custom Netcode logic to the associated NetworkObject.
 
+### What is a valid NetworkObject?
+
+There are two categories of NetworkObjects:
+* Dynamically instantiated
+* [In-scene placed](../../basics/scenemanagement/inscene-placed-networkobjects.md)
+
+The following provides the validity requirements for both types.
+
+#### Dynamically instantiated network prefabs
+
+Dynamically instantiated network prefabs must:
+
+* Be a valid [network prefab](./networkobject.md#network-prefabs) created within the Editor.
+* Be registered in a network prefab list that's assigned to your NetworkManager.
+
+#### In-scene placed network prefabs
+
+In-scene placed network prefabs must:
+
+* Be a valid network prefab instance within a scene.
+* Be a GameObject with a NetworkObject component created within the scene while in the Editor.
+
+### What is an invalid NetworkObject?
+
+GameObjects that have NetworkObject components added to them during runtime are **not supported** and will result in the NetworkObject's `GlobalObjectIdHash` being zero, which causes synchronization issues. In the event you make this mistake, a warning message will be logged and the NetworkObject won't be spawned.
+
 ### Component order
 
 The order of components on a networked GameObject matters. When adding netcode components to a GameObject, ensure that the NetworkObject component is ordered before any NetworkBehaviour components.

com.unity.netcode.gameobjects/Editor/InScenePlacedProcessor.cs

@@ -24,6 +24,12 @@ public void OnProcessScene(Scene scene, BuildReport report)
             log.AddInfo(scene.name, scene.handle);
             foreach (var networkObject in FindObjects.FromSceneByType<NetworkObject>(scene, true))
             {
+                // Trap for users just creating things during runtime where this will be zero.
+                if (networkObject.GlobalObjectIdHash == 0)
+                {
+                    log.Warning(new Context(LogLevel.Developer, $"{nameof(NetworkObject)}'s GlobalObjectIdHash value is zero! Runtime creating of {nameof(NetworkObject)}s is not supported. Skipping processing.").AddNetworkObject(networkObject));
+                    continue;
+                }
                 if (networkObject.SceneOrigin.IsValid() && networkObject.SceneOrigin.handle != scene.handle)
                 {
                     log.Warning(new Context(LogLevel.Developer, $"{nameof(NetworkObject)}'s SceneOrigin doesn't match current scene being processed! Skipping processing.").AddInfo("SceneOrigin", networkObject.SceneOriginHandle).AddNetworkObject(networkObject));
@@ -36,7 +42,15 @@ public void OnProcessScene(Scene scene, BuildReport report)
                     continue;
                 }
 
+                // If already marked, the do nothing.
+                if (networkObject.InScenePlaced)
+                {
+                    continue;
+                }
+
                 networkObject.InScenePlaced = true;
+                // Will not be true when making a build and the values are serialized.
+                networkObject.InScenePlacedPostProcessorMarkedDuringRuntime = Application.isPlaying;
             }
         }
     }

com.unity.netcode.gameobjects/Runtime/Components/NetworkAnimator.cs

@@ -768,7 +768,7 @@ protected virtual void Awake()
             if (!m_Animator)
             {
 #if !UNITY_EDITOR
-                Debug.LogError($"{nameof(NetworkAnimator)} {name} does not have an {nameof(UnityEngine.Animator)} assigned to it. The {nameof(NetworkAnimator)} will not initialize properly.");
+                Debug.LogWarning($"{nameof(NetworkAnimator)} {name} does not have an {nameof(UnityEngine.Animator)} assigned to it. The {nameof(NetworkAnimator)} will not initialize properly.");
 #endif
                 return;
             }

com.unity.netcode.gameobjects/Runtime/Configuration/NetworkPrefabs.cs

@@ -47,22 +47,110 @@ public class NetworkPrefabs
         [NonSerialized]
         private List<NetworkPrefab> m_Prefabs = new List<NetworkPrefab>();
 
+        /// <summary>
+        /// Returns the last registered prefab.
+        /// </summary>
+        internal NetworkPrefab GetLastRegisteredPrefab()
+        {
+            if (m_Prefabs.Count == 0)
+            {
+                return null;
+            }
+            return m_Prefabs[m_Prefabs.Count - 1];
+        }
+
+        /// <summary>
+        /// Applies a network prefab at a specific index
+        /// </summary>
+        /// <param name="index">index to apply</param>
+        /// <param name="networkPrefab">network prefab to be applied</param>
+        /// <returns></returns>
+        internal bool AssignPrefabAtIndex(int index, NetworkPrefab networkPrefab)
+        {
+            if (index >= m_Prefabs.Count)
+            {
+                NetworkManager.Singleton.Log.Error(new Logging.Context(LogLevel.Normal, $"[{nameof(NetworkPrefabs)}][{nameof(AssignPrefabAtIndex)}] Cannot apply prefab to index {index} when the {nameof(m_Prefabs)} count is only {m_Prefabs.Count}!"));
+                return false;
+            }
+            m_Prefabs[index] = networkPrefab;
+            return true;
+        }
+
+        [NonSerialized]
+        private Dictionary<uint, NetworkPrefab> m_PrefabHashIds = new Dictionary<uint, NetworkPrefab>();
+
         [NonSerialized]
         private List<NetworkPrefab> m_RuntimeAddedPrefabs = new List<NetworkPrefab>();
 
-        private void AddTriggeredByNetworkPrefabList(NetworkPrefab networkPrefab)
+        private bool InternalAddPrefab(NetworkPrefab networkPrefab)
         {
             if (AddPrefabRegistration(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.
                 m_Prefabs.Add(networkPrefab);
+
+                // We are not getting all potential overrides but just determining if the prefab has been registered.
+                if (!m_PrefabHashIds.ContainsKey(networkPrefab.SourcePrefabGlobalObjectIdHash))
+                {
+                    m_PrefabHashIds.Add(networkPrefab.SourcePrefabGlobalObjectIdHash, networkPrefab);
+                }
+                if (!m_PrefabHashIds.ContainsKey(networkPrefab.TargetPrefabGlobalObjectIdHash))
+                {
+                    m_PrefabHashIds.Add(networkPrefab.TargetPrefabGlobalObjectIdHash, networkPrefab);
+                }
+                return true;
             }
+            return false;
         }
 
-        private void RemoveTriggeredByNetworkPrefabList(NetworkPrefab networkPrefab)
+        private void InternalRemovePrefab(NetworkPrefab networkPrefab)
         {
             m_Prefabs.Remove(networkPrefab);
+            m_PrefabHashIds.Remove(networkPrefab.SourcePrefabGlobalObjectIdHash);
+        }
+
+        internal bool IsBasedOnRegisteredPrefab(NetworkObject networkObject)
+        {
+
+
+            return m_PrefabHashIds.ContainsKey(networkObject.GlobalObjectIdHash);
+        }
+
+        internal bool IsActualPrefabAsset(NetworkObject networkObject)
+        {
+            var isActualPrefabAsset = false;
+            if (m_PrefabHashIds.TryGetValue(networkObject.GlobalObjectIdHash, out NetworkPrefab networkPrefab))
+            {
+                switch (networkPrefab.Override)
+                {
+                    case NetworkPrefabOverride.Prefab:
+                    case NetworkPrefabOverride.None:
+                        {
+                            isActualPrefabAsset = networkPrefab.Prefab != null && networkObject.gameObject == networkPrefab.Prefab;
+                            break;
+                        }
+                    case NetworkPrefabOverride.Hash:
+                        {
+                            isActualPrefabAsset = networkPrefab.SourceHashToOverride == networkObject.GlobalObjectIdHash;
+                            break;
+                        }
+                }
+            }
+            return isActualPrefabAsset;
+        }
+
+        private void AddTriggeredByNetworkPrefabList(NetworkPrefab 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.
+            InternalAddPrefab(networkPrefab);
+            // Log warning if this returns false?
+        }
+
+        private void RemoveTriggeredByNetworkPrefabList(NetworkPrefab networkPrefab)
+        {
+            InternalRemovePrefab(networkPrefab);
         }
 
         /// <summary>
@@ -93,6 +181,7 @@ 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)
         {
+            m_PrefabHashIds.Clear();
             m_Prefabs.Clear();
             NetworkPrefabsLists.RemoveAll(x => x == null);
             foreach (var list in NetworkPrefabsLists)
@@ -113,7 +202,7 @@ public void Initialize(bool warnInvalid = true)
                     prefabs.AddRange(list.PrefabList);
                 }
             }
-
+            m_PrefabHashIds = new Dictionary<uint, NetworkPrefab>();
             m_Prefabs = new List<NetworkPrefab>();
 
             List<NetworkPrefab> removeList = null;
@@ -124,23 +213,15 @@ public void Initialize(bool warnInvalid = true)
 
             foreach (var networkPrefab in prefabs)
             {
-                if (AddPrefabRegistration(networkPrefab))
-                {
-                    m_Prefabs.Add(networkPrefab);
-                }
-                else
+                if (!InternalAddPrefab(networkPrefab))
                 {
                     removeList?.Add(networkPrefab);
                 }
             }
 
             foreach (var networkPrefab in m_RuntimeAddedPrefabs)
             {
-                if (AddPrefabRegistration(networkPrefab))
-                {
-                    m_Prefabs.Add(networkPrefab);
-                }
-                else
+                if (!InternalAddPrefab(networkPrefab))
                 {
                     removeList?.Add(networkPrefab);
                 }
@@ -171,14 +252,12 @@ public void Initialize(bool warnInvalid = true)
         /// </remarks>
         public bool Add(NetworkPrefab networkPrefab)
         {
-            if (AddPrefabRegistration(networkPrefab))
+            var added = InternalAddPrefab(networkPrefab);
+            if (added)
             {
-                m_Prefabs.Add(networkPrefab);
                 m_RuntimeAddedPrefabs.Add(networkPrefab);
-                return true;
             }
-
-            return false;
+            return added;
         }
 
         /// <summary>
@@ -197,8 +276,7 @@ public void Remove(NetworkPrefab prefab)
             {
                 throw new ArgumentNullException(nameof(prefab));
             }
-
-            m_Prefabs.Remove(prefab);
+            InternalRemovePrefab(prefab);
             m_RuntimeAddedPrefabs.Remove(prefab);
             OverrideToNetworkPrefab.Remove(prefab.TargetPrefabGlobalObjectIdHash);
             NetworkPrefabOverrideLinks.Remove(prefab.SourcePrefabGlobalObjectIdHash);
@@ -294,14 +372,12 @@ private bool AddPrefabRegistration(NetworkPrefab networkPrefab)
 
             uint source = networkPrefab.SourcePrefabGlobalObjectIdHash;
             uint target = networkPrefab.TargetPrefabGlobalObjectIdHash;
-
             // Make sure the prefab isn't already registered.
             if (NetworkPrefabOverrideLinks.ContainsKey(source))
             {
-                var networkObject = networkPrefab.Prefab.GetComponent<NetworkObject>();
-
+                var nameOrHashOverride = networkPrefab.Override == NetworkPrefabOverride.Hash ? $"Hash: {networkPrefab.SourcePrefabGlobalObjectIdHash}" : networkPrefab.Prefab?.name;
                 // This should never happen, but in the case it somehow does log an error and remove the duplicate entry
-                Debug.LogError($"{nameof(NetworkPrefab)} ({networkObject.name}) has a duplicate {nameof(NetworkObject.GlobalObjectIdHash)} source entry value of: {source}!");
+                Debug.LogError($"{nameof(NetworkPrefab)} ({nameOrHashOverride}) has a duplicate {nameof(NetworkObject.GlobalObjectIdHash)} source entry value of: {source}!");
                 return false;
             }