fix: changing MessageHeader size type from short to ushort to avoid overflows on messages larger than 32k (#1292)

Co-authored-by: Andrew Spiering <andrews@unity3d.com>

Author: ShadauxCat

com.unity.netcode.gameobjects/Runtime/Messaging/MessageHeader.cs

@@ -16,6 +16,6 @@ internal struct MessageHeader
         /// <summary>
         /// The total size of the message, NOT including the header.
         /// </summary>
-        public short MessageSize;
+        public ushort MessageSize;
     }
 }

com.unity.netcode.gameobjects/Runtime/Messaging/MessagingSystem.cs

@@ -354,7 +354,7 @@ internal unsafe int SendMessage<TMessageType, TClientIdListType>(in TMessageType
                     writeQueueItem.Writer.TryBeginWrite(sizeof(MessageHeader) + tmpSerializer.Length);
                     var header = new MessageHeader
                     {
-                        MessageSize = (short)tmpSerializer.Length,
+                        MessageSize = (ushort)tmpSerializer.Length,
                         MessageType = m_MessageTypes[typeof(TMessageType)],
                     };
 

com.unity.netcode.gameobjects/Tests/Editor/Messaging/MessageReceivingTests.cs

@@ -78,7 +78,7 @@ public void WhenHandlingAMessage_ReceiveMethodIsCalled()
         {
             var messageHeader = new MessageHeader
             {
-                MessageSize = (short)UnsafeUtility.SizeOf<TestMessage>(),
+                MessageSize = (ushort)UnsafeUtility.SizeOf<TestMessage>(),
                 MessageType = m_MessagingSystem.GetMessageType(typeof(TestMessage)),
             };
             var message = GetMessage();
@@ -109,7 +109,7 @@ public void WhenHandlingIncomingData_ReceiveIsNotCalledBeforeProcessingIncomingM
             };
             var messageHeader = new MessageHeader
             {
-                MessageSize = (short)UnsafeUtility.SizeOf<TestMessage>(),
+                MessageSize = (ushort)UnsafeUtility.SizeOf<TestMessage>(),
                 MessageType = m_MessagingSystem.GetMessageType(typeof(TestMessage)),
             };
             var message = GetMessage();
@@ -143,7 +143,7 @@ public void WhenReceivingAMessageAndProcessingMessageQueue_ReceiveMethodIsCalled
             };
             var messageHeader = new MessageHeader
             {
-                MessageSize = (short)UnsafeUtility.SizeOf<TestMessage>(),
+                MessageSize = (ushort)UnsafeUtility.SizeOf<TestMessage>(),
                 MessageType = m_MessagingSystem.GetMessageType(typeof(TestMessage)),
             };
             var message = GetMessage();
@@ -179,7 +179,7 @@ public void WhenReceivingMultipleMessagesAndProcessingMessageQueue_ReceiveMethod
             };
             var messageHeader = new MessageHeader
             {
-                MessageSize = (short)UnsafeUtility.SizeOf<TestMessage>(),
+                MessageSize = (ushort)UnsafeUtility.SizeOf<TestMessage>(),
                 MessageType = m_MessagingSystem.GetMessageType(typeof(TestMessage)),
             };
             var message = GetMessage();