fix: Fixes warning logged on double-initialize of prefabs lists. (#2565)

* fix: Fixes warning logged on double-initialize of prefabs lists.

Also, makes adding prefabs before initializing the list no longer an error case - those prefabs are stored in a separate list so that during initialization, they can be re-added to the prefabs list after pulling in data from the NetworkPrefabsList ScriptableObjects.

* Changelog

* Update CHANGELOG.md

Re-ordering the changelog entries

---------

Co-authored-by: Noel Stephens <[email protected]>

Author: ShadauxCat

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -12,6 +12,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Fixed warning "Runtime Network Prefabs was not empty at initialization time." being erroneously logged when no runtime network prefabs had been added (#2565)
 - Fixed issue where some temporary debug console logging was left in a merged PR. (#2562)
 - Fixed the "Generate Default Network Prefabs List" setting not loading correctly and always reverting to being checked. (#2545)
 - Fixed issue where users could not use NetworkSceneManager.VerifySceneBeforeLoading to exclude runtime generated scenes from client synchronization. (#2550)
@@ -29,6 +30,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ## Changed
 
+- Adding network prefabs before NetworkManager initialization is now supported. (#2565)
 - Connecting clients being synchronized now switch to the server's active scene before spawning and synchronizing NetworkObjects. (#2532)
 - Updated `UnityTransport` dependency on `com.unity.transport` to 1.3.4. (#2533)
 - Improved performance of NetworkBehaviour initialization by replacing reflection when initializing NetworkVariables with compile-time code generation, which should help reduce hitching during additive scene loads. (#2522)

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

@@ -38,10 +38,15 @@ public class NetworkPrefabs
         [NonSerialized]
         private List<NetworkPrefab> m_Prefabs = new List<NetworkPrefab>();
 
+        [NonSerialized]
+        private List<NetworkPrefab> m_RuntimeAddedPrefabs = new List<NetworkPrefab>();
+
         private void AddTriggeredByNetworkPrefabList(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);
             }
         }
@@ -67,8 +72,6 @@ internal void Shutdown()
                 list.OnAdd -= AddTriggeredByNetworkPrefabList;
                 list.OnRemove -= RemoveTriggeredByNetworkPrefabList;
             }
-
-            NetworkPrefabsLists.Clear();
         }
 
         /// <summary>
@@ -77,13 +80,7 @@ internal void Shutdown()
         /// </summary>
         public void Initialize(bool warnInvalid = true)
         {
-            if (NetworkPrefabsLists.Count != 0 && m_Prefabs.Count > 0)
-            {
-                NetworkLog.LogWarning("Runtime Network Prefabs was not empty at initialization time. Network " +
-                    "Prefab registrations made before initialization will be replaced by NetworkPrefabsList.");
-                m_Prefabs.Clear();
-            }
-
+            m_Prefabs.Clear();
             foreach (var list in NetworkPrefabsLists)
             {
                 list.OnAdd += AddTriggeredByNetworkPrefabList;
@@ -93,7 +90,7 @@ public void Initialize(bool warnInvalid = true)
             NetworkPrefabOverrideLinks.Clear();
             OverrideToNetworkPrefab.Clear();
 
-            var prefabs = NetworkPrefabsLists.Count != 0 ? new List<NetworkPrefab>() : m_Prefabs;
+            var prefabs = new List<NetworkPrefab>();
 
             if (NetworkPrefabsLists.Count != 0)
             {
@@ -126,6 +123,18 @@ public void Initialize(bool warnInvalid = true)
                 }
             }
 
+            foreach (var networkPrefab in m_RuntimeAddedPrefabs)
+            {
+                if (AddPrefabRegistration(networkPrefab))
+                {
+                    m_Prefabs.Add(networkPrefab);
+                }
+                else
+                {
+                    removeList?.Add(networkPrefab);
+                }
+            }
+
             // Clear out anything that is invalid or not used
             if (removeList?.Count > 0)
             {
@@ -152,6 +161,7 @@ public bool Add(NetworkPrefab networkPrefab)
             if (AddPrefabRegistration(networkPrefab))
             {
                 m_Prefabs.Add(networkPrefab);
+                m_RuntimeAddedPrefabs.Add(networkPrefab);
                 return true;
             }
 
@@ -175,6 +185,7 @@ public void Remove(NetworkPrefab prefab)
             }
 
             m_Prefabs.Remove(prefab);
+            m_RuntimeAddedPrefabs.Remove(prefab);
             OverrideToNetworkPrefab.Remove(prefab.TargetPrefabGlobalObjectIdHash);
             NetworkPrefabOverrideLinks.Remove(prefab.SourcePrefabGlobalObjectIdHash);
         }
@@ -203,6 +214,15 @@ public void Remove(GameObject prefab)
                     return;
                 }
             }
+
+            for (int i = 0; i < m_RuntimeAddedPrefabs.Count; i++)
+            {
+                if (m_RuntimeAddedPrefabs[i].Prefab == prefab)
+                {
+                    Remove(m_RuntimeAddedPrefabs[i]);
+                    return;
+                }
+            }
         }
 
         /// <summary>

com.unity.netcode.gameobjects/Tests/Editor/NetworkManagerConfigurationTests.cs

@@ -305,5 +305,164 @@ public void WhenModifyingPrefabListUsingPrefabsListAPI_ModificationIsShared()
             Assert.IsTrue(sharedList.Contains(object2.gameObject));
             Assert.IsTrue(sharedList.Contains(object3.gameObject));
         }
+
+        [Test]
+        public void WhenCallingInitializeAfterAddingAPrefabUsingPrefabsAPI_ThePrefabStillExists()
+        {
+            // Setup
+            var networkManagerObject = new GameObject(nameof(NestedNetworkObjectPrefabCheck));
+            var networkManager = networkManagerObject.AddComponent<NetworkManager>();
+            networkManager.NetworkConfig = new NetworkConfig
+            {
+                NetworkTransport = networkManager.gameObject.AddComponent<UnityTransport>()
+            };
+
+            var networkManagerObject2 = new GameObject(nameof(NestedNetworkObjectPrefabCheck));
+            var networkManager2 = networkManagerObject2.AddComponent<NetworkManager>();
+            networkManager2.NetworkConfig = new NetworkConfig
+            {
+                NetworkTransport = networkManager.gameObject.AddComponent<UnityTransport>()
+            };
+
+            var object1 = new GameObject("Object 1").AddComponent<NetworkObject>();
+            var object2 = new GameObject("Object 2").AddComponent<NetworkObject>();
+            var object3 = new GameObject("Object 3").AddComponent<NetworkObject>();
+
+            object1.GlobalObjectIdHash = 1;
+            object2.GlobalObjectIdHash = 2;
+            object3.GlobalObjectIdHash = 3;
+
+            var sharedList = ScriptableObject.CreateInstance<NetworkPrefabsList>();
+            sharedList.List.Add(new NetworkPrefab { Prefab = object1.gameObject });
+
+            networkManager.NetworkConfig.Prefabs.NetworkPrefabsLists = new List<NetworkPrefabsList> { sharedList };
+            networkManager2.NetworkConfig.Prefabs.NetworkPrefabsLists = new List<NetworkPrefabsList> { sharedList };
+
+            networkManager.NetworkConfig.Prefabs.Add(new NetworkPrefab { Prefab = object2.gameObject });
+            networkManager2.NetworkConfig.Prefabs.Add(new NetworkPrefab { Prefab = object3.gameObject });
+
+            networkManager.Initialize(true);
+            networkManager2.Initialize(false);
+
+            Assert.IsTrue(networkManager.NetworkConfig.Prefabs.Contains(object1.gameObject));
+            Assert.IsTrue(networkManager2.NetworkConfig.Prefabs.Contains(object1.gameObject));
+            Assert.IsTrue(networkManager.NetworkConfig.Prefabs.Contains(object2.gameObject));
+            Assert.IsFalse(networkManager2.NetworkConfig.Prefabs.Contains(object2.gameObject));
+            Assert.IsTrue(networkManager2.NetworkConfig.Prefabs.Contains(object3.gameObject));
+            Assert.IsFalse(networkManager.NetworkConfig.Prefabs.Contains(object3.gameObject));
+
+            Assert.IsTrue(sharedList.Contains(object1.gameObject));
+            Assert.IsFalse(sharedList.Contains(object2.gameObject));
+            Assert.IsFalse(sharedList.Contains(object3.gameObject));
+        }
+
+        [Test]
+        public void WhenShuttingDownAndReinitializingPrefabs_RuntimeAddedPrefabsStillExists()
+        {
+            // Setup
+            var networkManagerObject = new GameObject(nameof(NestedNetworkObjectPrefabCheck));
+            var networkManager = networkManagerObject.AddComponent<NetworkManager>();
+            networkManager.NetworkConfig = new NetworkConfig
+            {
+                NetworkTransport = networkManager.gameObject.AddComponent<UnityTransport>()
+            };
+
+            var networkManagerObject2 = new GameObject(nameof(NestedNetworkObjectPrefabCheck));
+            var networkManager2 = networkManagerObject2.AddComponent<NetworkManager>();
+            networkManager2.NetworkConfig = new NetworkConfig
+            {
+                NetworkTransport = networkManager.gameObject.AddComponent<UnityTransport>()
+            };
+
+            var object1 = new GameObject("Object 1").AddComponent<NetworkObject>();
+            var object2 = new GameObject("Object 2").AddComponent<NetworkObject>();
+            var object3 = new GameObject("Object 3").AddComponent<NetworkObject>();
+
+            object1.GlobalObjectIdHash = 1;
+            object2.GlobalObjectIdHash = 2;
+            object3.GlobalObjectIdHash = 3;
+
+            var sharedList = ScriptableObject.CreateInstance<NetworkPrefabsList>();
+            sharedList.List.Add(new NetworkPrefab { Prefab = object1.gameObject });
+
+            networkManager.NetworkConfig.Prefabs.NetworkPrefabsLists = new List<NetworkPrefabsList> { sharedList };
+            networkManager2.NetworkConfig.Prefabs.NetworkPrefabsLists = new List<NetworkPrefabsList> { sharedList };
+
+            networkManager.Initialize(true);
+            networkManager2.Initialize(false);
+
+            networkManager.NetworkConfig.Prefabs.Add(new NetworkPrefab { Prefab = object2.gameObject });
+            networkManager2.NetworkConfig.Prefabs.Add(new NetworkPrefab { Prefab = object3.gameObject });
+
+            networkManager.ShutdownInternal();
+            networkManager2.ShutdownInternal();
+
+            networkManager.Initialize(true);
+            networkManager2.Initialize(false);
+
+            Assert.IsTrue(networkManager.NetworkConfig.Prefabs.Contains(object1.gameObject));
+            Assert.IsTrue(networkManager2.NetworkConfig.Prefabs.Contains(object1.gameObject));
+            Assert.IsTrue(networkManager.NetworkConfig.Prefabs.Contains(object2.gameObject));
+            Assert.IsFalse(networkManager2.NetworkConfig.Prefabs.Contains(object2.gameObject));
+            Assert.IsTrue(networkManager2.NetworkConfig.Prefabs.Contains(object3.gameObject));
+            Assert.IsFalse(networkManager.NetworkConfig.Prefabs.Contains(object3.gameObject));
+
+            Assert.IsTrue(sharedList.Contains(object1.gameObject));
+            Assert.IsFalse(sharedList.Contains(object2.gameObject));
+            Assert.IsFalse(sharedList.Contains(object3.gameObject));
+        }
+
+        [Test]
+        public void WhenCallingInitializeMultipleTimes_NothingBreaks()
+        {
+            // Setup
+            var networkManagerObject = new GameObject(nameof(NestedNetworkObjectPrefabCheck));
+            var networkManager = networkManagerObject.AddComponent<NetworkManager>();
+            networkManager.NetworkConfig = new NetworkConfig
+            {
+                NetworkTransport = networkManager.gameObject.AddComponent<UnityTransport>()
+            };
+
+            var networkManagerObject2 = new GameObject(nameof(NestedNetworkObjectPrefabCheck));
+            var networkManager2 = networkManagerObject2.AddComponent<NetworkManager>();
+            networkManager2.NetworkConfig = new NetworkConfig
+            {
+                NetworkTransport = networkManager.gameObject.AddComponent<UnityTransport>()
+            };
+
+            var object1 = new GameObject("Object 1").AddComponent<NetworkObject>();
+            var object2 = new GameObject("Object 2").AddComponent<NetworkObject>();
+            var object3 = new GameObject("Object 3").AddComponent<NetworkObject>();
+
+            object1.GlobalObjectIdHash = 1;
+            object2.GlobalObjectIdHash = 2;
+            object3.GlobalObjectIdHash = 3;
+
+            var sharedList = ScriptableObject.CreateInstance<NetworkPrefabsList>();
+            sharedList.List.Add(new NetworkPrefab { Prefab = object1.gameObject });
+
+            networkManager.NetworkConfig.Prefabs.NetworkPrefabsLists = new List<NetworkPrefabsList> { sharedList };
+            networkManager2.NetworkConfig.Prefabs.NetworkPrefabsLists = new List<NetworkPrefabsList> { sharedList };
+
+            networkManager.Initialize(true);
+            networkManager2.Initialize(false);
+
+            networkManager.NetworkConfig.Prefabs.Add(new NetworkPrefab { Prefab = object2.gameObject });
+            networkManager2.NetworkConfig.Prefabs.Add(new NetworkPrefab { Prefab = object3.gameObject });
+
+            networkManager.NetworkConfig.Prefabs.Initialize();
+            networkManager2.NetworkConfig.Prefabs.Initialize();
+
+            Assert.IsTrue(networkManager.NetworkConfig.Prefabs.Contains(object1.gameObject));
+            Assert.IsTrue(networkManager2.NetworkConfig.Prefabs.Contains(object1.gameObject));
+            Assert.IsTrue(networkManager.NetworkConfig.Prefabs.Contains(object2.gameObject));
+            Assert.IsFalse(networkManager2.NetworkConfig.Prefabs.Contains(object2.gameObject));
+            Assert.IsTrue(networkManager2.NetworkConfig.Prefabs.Contains(object3.gameObject));
+            Assert.IsFalse(networkManager.NetworkConfig.Prefabs.Contains(object3.gameObject));
+
+            Assert.IsTrue(sharedList.Contains(object1.gameObject));
+            Assert.IsFalse(sharedList.Contains(object2.gameObject));
+            Assert.IsFalse(sharedList.Contains(object3.gameObject));
+        }
     }
 }