fix: server scene exclusion during synchronization for runtime generated scenes

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -14,6 +14,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 - 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)
 - Fixed missing value on `NetworkListEvent` for `EventType.RemoveAt` events.  (#2542,#2543)
 - Fixed issue where parenting a NetworkTransform under a transform with a scale other than Vector3.one would result in incorrect values on non-authoritative instances. (#2538)
 - Fixed issue where a server would include scene migrated and then despawned NetworkObjects to a client that was being synchronized. (#2532)

com.unity.netcode.gameobjects/Runtime/SceneManagement/NetworkSceneManager.cs

@@ -786,9 +786,18 @@ private void SceneManager_ActiveSceneChanged(Scene current, Scene next)
         /// <returns>true (Valid) or false (Invalid)</returns>
         internal bool ValidateSceneBeforeLoading(uint sceneHash, LoadSceneMode loadSceneMode)
         {
-            var validated = true;
             var sceneName = SceneNameFromHash(sceneHash);
             var sceneIndex = SceneUtility.GetBuildIndexByScenePath(sceneName);
+            return ValidateSceneBeforeLoading(sceneIndex, sceneName, loadSceneMode);
+        }
+
+        /// <summary>
+        /// Overloaded version that is invoked by <see cref="ValidateSceneBeforeLoading"/> and <see cref="SynchronizeNetworkObjects"/>.
+        /// This specifically is to allow runtime generated scenes to be excluded by the server during synchronization.
+        /// </summary>
+        internal bool ValidateSceneBeforeLoading(int sceneIndex, string sceneName, LoadSceneMode loadSceneMode)
+        {
+            var validated = true;
             if (VerifySceneBeforeLoading != null)
             {
                 validated = VerifySceneBeforeLoading.Invoke(sceneIndex, sceneName, loadSceneMode);
@@ -1744,24 +1753,22 @@ internal void SynchronizeNetworkObjects(ulong clientId)
                     continue;
                 }
 
-                var sceneHash = SceneHashFromNameOrPath(scene.path);
-
                 // This would depend upon whether we are additive or not
                 // If we are the base scene, then we set the root scene index;
                 if (activeScene == scene)
                 {
-                    if (!ValidateSceneBeforeLoading(sceneHash, sceneEventData.LoadSceneMode))
+                    if (!ValidateSceneBeforeLoading(scene.buildIndex, scene.name, sceneEventData.LoadSceneMode))
                     {
                         continue;
                     }
-                    sceneEventData.SceneHash = sceneHash;
+                    sceneEventData.SceneHash = SceneHashFromNameOrPath(scene.path);
                     sceneEventData.SceneHandle = scene.handle;
                 }
-                else if (!ValidateSceneBeforeLoading(sceneHash, LoadSceneMode.Additive))
+                else if (!ValidateSceneBeforeLoading(scene.buildIndex, scene.name, LoadSceneMode.Additive))
                 {
                     continue;
                 }
-                sceneEventData.AddSceneToSynchronize(sceneHash, scene.handle);
+                sceneEventData.AddSceneToSynchronize(SceneHashFromNameOrPath(scene.path), scene.handle);
             }
 
             sceneEventData.AddSpawnedNetworkObjects();

testproject/Assets/Tests/Runtime/NetworkSceneManager/ClientSynchronizationValidationTest.cs

@@ -15,18 +15,69 @@ public class ClientSynchronizationValidationTest : NetcodeIntegrationTest
         private const string k_FirstSceneToLoad = "UnitTestBaseScene";
         private const string k_SecondSceneToLoad = "InSceneNetworkObject";
         private const string k_ThirdSceneToSkip = "EmptyScene";
+        private Scene m_RuntimeGeneratedScene;
+        private bool m_IncludeSceneVerificationHandler;
+        private bool m_RuntimeSceneWasExcludedFromSynch;
 
         private List<ClientSceneVerificationHandler> m_ClientSceneVerifiers = new List<ClientSceneVerificationHandler>();
 
         protected override void OnNewClientStarted(NetworkManager networkManager)
         {
-            m_ClientSceneVerifiers.Add(new ClientSceneVerificationHandler(networkManager));
+            if (m_IncludeSceneVerificationHandler)
+            {
+                m_ClientSceneVerifiers.Add(new ClientSceneVerificationHandler(networkManager));
+            }
             base.OnNewClientStarted(networkManager);
         }
 
+        /// <summary>
+        /// Handle excluding runtime scene from synchronization
+        /// </summary>
+        private bool OnServerVerifySceneBeforeLoading(int sceneIndex, string sceneName, LoadSceneMode loadSceneMode)
+        {
+            // exclude test runner scene
+            if (sceneName.StartsWith(NetcodeIntegrationTestHelpers.FirstPartOfTestRunnerSceneName))
+            {
+                return false;
+            }
+
+            // Exclude the runtime generated scene
+            if (sceneIndex == m_RuntimeGeneratedScene.buildIndex && m_RuntimeGeneratedScene.name == sceneName)
+            {
+                m_RuntimeSceneWasExcludedFromSynch = true;
+                return false;
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        /// Test that validates users can exclude runtime generated scenes from the initial client synchronization
+        /// process using <see cref="NetworkSceneManager.VerifySceneBeforeLoading"/>
+        /// </summary>
+        [UnityTest]
+        public IEnumerator ClientSynchWithServerSideRuntimeGeneratedScene()
+        {
+            m_IncludeSceneVerificationHandler = false;
+            m_ServerNetworkManager.SceneManager.VerifySceneBeforeLoading = OnServerVerifySceneBeforeLoading;
+            m_ServerNetworkManager.SceneManager.DisableValidationWarnings(true);
+            // For this test we want to disable the check for scenes in build list
+            m_ServerNetworkManager.SceneManager.ExcludeSceneFromSychronization = null;
+            // Create a runtime scene in the server side
+            m_RuntimeGeneratedScene = SceneManager.CreateScene("RuntimeGeneratedScene");
+            yield return s_DefaultWaitForTick;
+            yield return CreateAndStartNewClient();
+
+            Assert.True(m_RuntimeSceneWasExcludedFromSynch, $"Server did not exclude the runtime generated scene when creating synchronization message data!");
+        }
+
+        /// <summary>
+        /// Validates that connecting clients will exclude scenes using <see cref="NetworkSceneManager.VerifySceneBeforeLoading"/>
+        /// </summary>
         [UnityTest]
         public IEnumerator ClientVerifySceneBeforeLoading()
         {
+            m_IncludeSceneVerificationHandler = true;
             var scenesToLoad = new List<string>() { k_FirstSceneToLoad, k_SecondSceneToLoad, k_ThirdSceneToSkip };
             m_ServerNetworkManager.SceneManager.OnLoadComplete += OnLoadComplete;
             foreach (var sceneToLoad in scenesToLoad)