fix: Use GetStableHashCode16 instead of truncation (#4102)

Author: MrGadget1024

Assets/Mirror/Core/NetworkBehaviour.cs

@@ -364,7 +364,7 @@ protected void InitSyncObject(SyncObject syncObject)
         }
 
         // pass full function name to avoid ClassA.Func <-> ClassB.Func collisions
-        protected void SendCommandInternal(string functionFullName, int functionHashCode, NetworkWriter writer, int channelId, bool requiresAuthority = true)
+        protected void SendCommandInternal(string functionFullName, ushort functionHashCode, NetworkWriter writer, int channelId, bool requiresAuthority = true)
         {
             // this was in Weaver before
             // NOTE: we could remove this later to allow calling Cmds on Server
@@ -418,7 +418,7 @@ protected void SendCommandInternal(string functionFullName, int functionHashCode
                 netId = netId,
                 componentIndex = ComponentIndex,
                 // type+func so Inventory.RpcUse != Equipment.RpcUse
-                functionHash = (ushort)functionHashCode,
+                functionHash = functionHashCode,
                 // segment to avoid reader allocations
                 payload = writer.ToArraySegment()
             };
@@ -434,7 +434,7 @@ protected void SendCommandInternal(string functionFullName, int functionHashCode
         }
 
         // pass full function name to avoid ClassA.Func <-> ClassB.Func collisions
-        protected void SendRPCInternal(string functionFullName, int functionHashCode, NetworkWriter writer, int channelId, bool includeOwner)
+        protected void SendRPCInternal(string functionFullName, ushort functionHashCode, NetworkWriter writer, int channelId, bool includeOwner)
         {
             // this was in Weaver before
             if (!NetworkServer.active)
@@ -456,7 +456,7 @@ protected void SendRPCInternal(string functionFullName, int functionHashCode, Ne
                 netId = netId,
                 componentIndex = ComponentIndex,
                 // type+func so Inventory.RpcUse != Equipment.RpcUse
-                functionHash = (ushort)functionHashCode,
+                functionHash = functionHashCode,
                 // segment to avoid reader allocations
                 payload = writer.ToArraySegment()
             };
@@ -488,7 +488,7 @@ protected void SendRPCInternal(string functionFullName, int functionHashCode, Ne
         }
 
         // pass full function name to avoid ClassA.Func <-> ClassB.Func collisions
-        protected void SendTargetRPCInternal(NetworkConnection conn, string functionFullName, int functionHashCode, NetworkWriter writer, int channelId)
+        protected void SendTargetRPCInternal(NetworkConnection conn, string functionFullName, ushort functionHashCode, NetworkWriter writer, int channelId)
         {
             if (!NetworkServer.active)
             {
@@ -527,7 +527,7 @@ protected void SendTargetRPCInternal(NetworkConnection conn, string functionFull
                 netId = netId,
                 componentIndex = ComponentIndex,
                 // type+func so Inventory.RpcUse != Equipment.RpcUse
-                functionHash = (ushort)functionHashCode,
+                functionHash = functionHashCode,
                 // segment to avoid reader allocations
                 payload = writer.ToArraySegment()
             };

Assets/Mirror/Core/RemoteCalls.cs

@@ -70,7 +70,7 @@ static bool CheckIfDelegateExists(Type componentType, RemoteCallType remoteCallT
         internal static ushort RegisterDelegate(Type componentType, string functionFullName, RemoteCallType remoteCallType, RemoteCallDelegate func, bool cmdRequiresAuthority = true)
         {
             // type+func so Inventory.RpcUse != Equipment.RpcUse
-            ushort hash = (ushort)(functionFullName.GetStableHashCode() & 0xFFFF);
+            ushort hash = functionFullName.GetStableHashCode16();
 
             if (CheckIfDelegateExists(componentType, remoteCallType, func, hash))
                 return hash;

Assets/Mirror/Editor/Weaver/Processors/CommandProcessor.cs

@@ -128,7 +128,7 @@ public static MethodDefinition ProcessCommandCall(WeaverTypes weaverTypes, Write
             // otherwise each GetStableHash call requires O(N) complexity.
             // noticeable for long function names:
             // https://github.com/MirrorNetworking/Mirror/issues/3375
-            worker.Emit(OpCodes.Ldc_I4, md.FullName.GetStableHashCode());
+            worker.Emit(OpCodes.Ldc_I4, md.FullName.GetStableHashCode16());
             // writer
             worker.Emit(OpCodes.Ldloc_0);
             worker.Emit(OpCodes.Ldc_I4, channel);

Assets/Mirror/Editor/Weaver/Processors/RpcProcessor.cs

@@ -86,7 +86,7 @@ public static MethodDefinition ProcessRpcCall(WeaverTypes weaverTypes, Writers w
             // otherwise each GetStableHash call requires O(N) complexity.
             // noticeable for long function names: 
             // https://github.com/MirrorNetworking/Mirror/issues/3375
-            worker.Emit(OpCodes.Ldc_I4, md.FullName.GetStableHashCode());
+            worker.Emit(OpCodes.Ldc_I4, md.FullName.GetStableHashCode16());
             // writer
             worker.Emit(OpCodes.Ldloc_0);
             worker.Emit(OpCodes.Ldc_I4, channel);

Assets/Mirror/Editor/Weaver/Processors/TargetRpcProcessor.cs

@@ -143,7 +143,7 @@ public static MethodDefinition ProcessTargetRpcCall(WeaverTypes weaverTypes, Wri
             // otherwise each GetStableHash call requires O(N) complexity.
             // noticeable for long function names:
             // https://github.com/MirrorNetworking/Mirror/issues/3375
-            worker.Emit(OpCodes.Ldc_I4, md.FullName.GetStableHashCode());
+            worker.Emit(OpCodes.Ldc_I4, md.FullName.GetStableHashCode16());
             // writer
             worker.Emit(OpCodes.Ldloc_0);
             worker.Emit(OpCodes.Ldc_I4, targetRpcAttr.GetField("channel", 0));

Assets/Mirror/Tests/Editor/NetworkBehaviour/NetworkBehaviourTests.cs

@@ -201,7 +201,7 @@ public void GetDelegate()
                 false);
 
             // get handler
-            ushort cmdHash = (ushort)nameof(NetworkBehaviourDelegateComponent.Delegate).GetStableHashCode();
+            ushort cmdHash = nameof(NetworkBehaviourDelegateComponent.Delegate).GetStableHashCode16();
             RemoteCallDelegate func = RemoteProcedureCalls.GetDelegate(cmdHash);
             RemoteCallDelegate expected = NetworkBehaviourDelegateComponent.Delegate;
             Assert.That(func, Is.EqualTo(expected));