feat: Add "RemoveNetworkPrefab" which is necessary for certain addressables implementations

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -10,6 +10,8 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Added
 
+- Added `NetworkManager.RemoveNetworkPrefab(...)` to remove a prefab from the prefabs list (#1950)
+
 ### Changed
 
 ### Removed

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

@@ -541,6 +541,47 @@ public void AddNetworkPrefab(GameObject prefab)
             }
         }
 
+        /// <summary>
+        /// Remove a prefab from the prefab list.
+        /// As with AddNetworkPrefab, this is specific to the client it's called on -
+        /// calling it on the server does not automatically remove anything on any of the
+        /// client processes.
+        ///
+        /// Like AddNetworkPrefab, when NetworkConfig.ForceSamePrefabs is enabled,
+        /// this cannot be called after connecting.
+        /// </summary>
+        /// <param name="prefab"></param>
+        public void RemoveNetworkPrefab(GameObject prefab)
+        {
+            if (IsListening && NetworkConfig.ForceSamePrefabs)
+            {
+                throw new Exception($"Prefabs cannot be removed after starting {nameof(NetworkManager)} when {nameof(NetworkConfig.ForceSamePrefabs)} is enabled.");
+            }
+
+            var globalObjectIdHash = prefab.GetComponent<NetworkObject>().GlobalObjectIdHash;
+            for (var i = 0; i < NetworkConfig.NetworkPrefabs.Count; ++i)
+            {
+                if (NetworkConfig.NetworkPrefabs[i].Prefab.GetComponent<NetworkObject>().GlobalObjectIdHash == globalObjectIdHash)
+                {
+                    NetworkConfig.NetworkPrefabs.RemoveAt(i);
+                    break;
+                }
+            }
+            if (PrefabHandler.ContainsHandler(globalObjectIdHash))
+            {
+                PrefabHandler.RemoveHandler(globalObjectIdHash);
+            }
+            if (NetworkConfig.NetworkPrefabOverrideLinks.TryGetValue(globalObjectIdHash, out var targetPrefab))
+            {
+                NetworkConfig.NetworkPrefabOverrideLinks.Remove(globalObjectIdHash);
+                var targetHash = targetPrefab.Prefab.GetComponent<NetworkObject>().GlobalObjectIdHash;
+                if (NetworkConfig.OverrideToNetworkPrefab.ContainsKey(targetHash))
+                {
+                    NetworkConfig.OverrideToNetworkPrefab.Remove(targetHash);
+                }
+            }
+        }
+
         private bool ShouldAddPrefab(NetworkPrefab networkPrefab, out uint sourcePrefabGlobalObjectIdHash, out uint targetPrefabGlobalObjectIdHash, int index = -1)
         {
             sourcePrefabGlobalObjectIdHash = 0;

com.unity.netcode.gameobjects/Tests/Runtime/AddNetworkPrefabTests.cs

@@ -0,0 +1,136 @@
+using System.Collections;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.TestTools;
+using Unity.Netcode.TestHelpers.Runtime;
+using Object = UnityEngine.Object;
+
+namespace Unity.Netcode.RuntimeTests
+{
+    public class AddNetworkPrefabTest : NetcodeIntegrationTest
+    {
+        public class EmptyComponent : NetworkBehaviour
+        {
+
+        }
+        protected override int NumberOfClients => 1;
+
+        private GameObject m_Prefab;
+
+        protected override IEnumerator OnSetup()
+        {
+            // Host is irrelevant, messages don't get sent to the host "client"
+            m_UseHost = false;
+
+            m_Prefab = new GameObject("Object");
+            var networkObject = m_Prefab.AddComponent<NetworkObject>();
+            m_Prefab.AddComponent<EmptyComponent>();
+
+            // Make it a prefab
+            NetcodeIntegrationTestHelpers.MakeNetworkObjectTestPrefab(networkObject);
+            yield return null;
+        }
+
+        protected override void OnServerAndClientsCreated()
+        {
+            m_ServerNetworkManager.NetworkConfig.SpawnTimeout = 0;
+            m_ServerNetworkManager.NetworkConfig.ForceSamePrefabs = false;
+            foreach (var client in m_ClientNetworkManagers)
+            {
+                client.NetworkConfig.SpawnTimeout = 0;
+                client.NetworkConfig.ForceSamePrefabs = false;
+            }
+        }
+
+        private EmptyComponent GetObjectForClient(ulong clientId)
+        {
+            foreach (var component in Object.FindObjectsOfType<EmptyComponent>())
+            {
+                if (component.IsSpawned && component.NetworkManager.LocalClientId == clientId)
+                {
+                    return component;
+                }
+            }
+
+            return null;
+        }
+
+        private void RegisterPrefab()
+        {
+            m_ServerNetworkManager.AddNetworkPrefab(m_Prefab);
+            foreach (var client in m_ClientNetworkManagers)
+            {
+                client.AddNetworkPrefab(m_Prefab);
+            }
+        }
+
+        private void DeregisterPrefab()
+        {
+            m_ServerNetworkManager.RemoveNetworkPrefab(m_Prefab);
+            foreach (var client in m_ClientNetworkManagers)
+            {
+                client.RemoveNetworkPrefab(m_Prefab);
+            }
+        }
+
+        private static CoroutineRunner s_CoroutineRunner;
+
+        [UnityTest]
+        public IEnumerator WhenSpawningBeforeAddingPrefab_SpawnFails()
+        {
+            var serverObject = Object.Instantiate(m_Prefab);
+            serverObject.GetComponent<NetworkObject>().NetworkManagerOwner = m_ServerNetworkManager;
+            serverObject.GetComponent<NetworkObject>().Spawn();
+            yield return NetcodeIntegrationTestHelpers.WaitForMessageOfTypeReceived<CreateObjectMessage>(m_ClientNetworkManagers[0]);
+            Assert.IsNull(GetObjectForClient(m_ClientNetworkManagers[0].LocalClientId));
+        }
+
+        [UnityTest]
+        public IEnumerator WhenSpawningAfterAddingServerPrefabButBeforeAddingClientPrefab_SpawnFails()
+        {
+            m_ServerNetworkManager.AddNetworkPrefab(m_Prefab);
+
+            var serverObject = Object.Instantiate(m_Prefab);
+            serverObject.GetComponent<NetworkObject>().NetworkManagerOwner = m_ServerNetworkManager;
+            serverObject.GetComponent<NetworkObject>().Spawn();
+            yield return NetcodeIntegrationTestHelpers.WaitForMessageOfTypeReceived<CreateObjectMessage>(m_ClientNetworkManagers[0]);
+            Assert.IsNull(GetObjectForClient(m_ClientNetworkManagers[0].LocalClientId));
+        }
+
+        [UnityTest]
+        public IEnumerator WhenSpawningAfterAddingPrefabOnServerAndClient_SpawnSucceeds()
+        {
+            RegisterPrefab();
+
+            var serverObject = Object.Instantiate(m_Prefab);
+            serverObject.GetComponent<NetworkObject>().NetworkManagerOwner = m_ServerNetworkManager;
+            serverObject.GetComponent<NetworkObject>().Spawn();
+            yield return NetcodeIntegrationTestHelpers.WaitForMessageOfTypeHandled<CreateObjectMessage>(m_ClientNetworkManagers[0]);
+            Assert.IsNotNull(GetObjectForClient(m_ClientNetworkManagers[0].LocalClientId));
+        }
+
+        [UnityTest]
+        public IEnumerator WhenSpawningAfterRemovingPrefabOnClient_SpawnFails()
+        {
+            RegisterPrefab();
+
+            var serverObject = Object.Instantiate(m_Prefab);
+            serverObject.GetComponent<NetworkObject>().NetworkManagerOwner = m_ServerNetworkManager;
+            serverObject.GetComponent<NetworkObject>().Spawn();
+            yield return NetcodeIntegrationTestHelpers.WaitForMessageOfTypeReceived<CreateObjectMessage>(m_ClientNetworkManagers[0]);
+            Assert.IsNotNull(GetObjectForClient(m_ClientNetworkManagers[0].LocalClientId));
+
+            serverObject.GetComponent<NetworkObject>().Despawn();
+            yield return NetcodeIntegrationTestHelpers.WaitForMessageOfTypeReceived<DestroyObjectMessage>(m_ClientNetworkManagers[0]);
+            Assert.IsNull(GetObjectForClient(m_ClientNetworkManagers[0].LocalClientId));
+
+            DeregisterPrefab();
+
+            serverObject = Object.Instantiate(m_Prefab);
+            serverObject.GetComponent<NetworkObject>().NetworkManagerOwner = m_ServerNetworkManager;
+            serverObject.GetComponent<NetworkObject>().Spawn();
+            yield return NetcodeIntegrationTestHelpers.WaitForMessageOfTypeReceived<CreateObjectMessage>(m_ClientNetworkManagers[0]);
+            Assert.IsNull(GetObjectForClient(m_ClientNetworkManagers[0].LocalClientId));
+        }
+    }
+}