fix: Fixed an exception when EnsureNetworkVariableLengthSafety is enabled

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -28,6 +28,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 - Fixed NetworkObjects not being despawned before they are destroyed during shutdown for client, host, and server instances. (#1390)
 - Fixed client player object being destroyed on server when the client's player object has DontDestroyWithOwner set. (#1433)
+- Fixed an exception being thrown during NetworkVariableDeltaMessage serialization when EnsureNetworkVariableLengthSafety is enabled (#1487)
 - Fixed: NetworkVariables containing more than 1300 bytes of data (such as large NetworkLists) no longer cause an OverflowException (the limit on data size is now whatever limit the chosen transport imposes on fragmented NetworkDelivery mechanisms) (#1481)
 - Fixed KeyNotFound exception when removing ownership of a newly spawned NetworkObject that is already owned by the server. (#1500)
 

com.unity.netcode.gameobjects/Runtime/Messaging/Messages/NetworkVariableDeltaMessage.cs

@@ -38,7 +38,7 @@ public void Serialize(FastBufferWriter writer)
                     // This var does not belong to the currently iterating delivery group.
                     if (NetworkBehaviour.NetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety)
                     {
-                        writer.WriteValueSafe((short)0);
+                        writer.WriteValueSafe((ushort)0);
                     }
                     else
                     {
@@ -71,7 +71,11 @@ public void Serialize(FastBufferWriter writer)
                         var tmpWriter = new FastBufferWriter(MessagingSystem.NON_FRAGMENTED_MESSAGE_MAX_SIZE, Allocator.Temp, short.MaxValue);
                         NetworkBehaviour.NetworkVariableFields[k].WriteDelta(tmpWriter);
 
-                        writer.WriteValueSafe((ushort)tmpWriter.Length);
+                        if (!writer.TryBeginWrite(FastBufferWriter.GetWriteSize<ushort>() + tmpWriter.Length))
+                        {
+                            throw new OverflowException($"Not enough space in the buffer to write {nameof(NetworkVariableDeltaMessage)}");
+                        }
+                        writer.WriteValue((ushort)tmpWriter.Length);
                         tmpWriter.CopyTo(writer);
                     }
                     else

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

@@ -52,6 +52,8 @@ public void Awake()
         public bool ListDelegateTriggered;
     }
 
+    [TestFixture(true)]
+    [TestFixture(false)]
     public class NetworkVariableTests : BaseMultiInstanceTest
     {
         private const string k_FixedStringTestValue = "abcdefghijklmnopqrstuvwxyz";
@@ -73,6 +75,13 @@ public class NetworkVariableTests : BaseMultiInstanceTest
 
         private bool m_TestWithHost;
 
+        private bool m_EnsureLengthSafety;
+
+        public NetworkVariableTests(bool ensureLengthSafety)
+        {
+            m_EnsureLengthSafety = ensureLengthSafety;
+        }
+
         [UnitySetUp]
         public override IEnumerator Setup()
         {
@@ -82,6 +91,12 @@ public override IEnumerator Setup()
                     playerPrefab.AddComponent<NetworkVariableTest>();
                 });
 
+            m_ServerNetworkManager.NetworkConfig.EnsureNetworkVariableLengthSafety = m_EnsureLengthSafety;
+            foreach (var client in m_ClientNetworkManagers)
+            {
+                client.NetworkConfig.EnsureNetworkVariableLengthSafety = m_EnsureLengthSafety;
+            }
+
             // These are the *SERVER VERSIONS* of the *CLIENT PLAYER 1 & 2*
             var result = new MultiInstanceHelpers.CoroutineResultWrapper<NetworkObject>();