Fix calling Send using UM instance from UM hook (#578)

Author: Yarukon

src/core/UserMessage.h

@@ -132,6 +132,7 @@ class UserMessage
     const CNetMessagePB<google::protobuf::Message>* GetProtobufMessage();
     INetworkMessageInternal* GetSerializableMessage() { return msgSerializable; }
     uint64* GetRecipientMask() { return recipientMask; }
+    bool IsManuallyAllocated() { return manuallyAllocated; }
 
   private:
     CNetMessagePB<google::protobuf::Message>* msg = nullptr;

src/scripting/natives/natives_usermessages.cpp

@@ -620,7 +620,13 @@ static void UserMessageSend(ScriptContext& scriptContext)
     CRecipientFilter filter{};
     filter.AddRecipientsFromMask(message->GetRecipientMask() ? *message->GetRecipientMask() : 0);
 
-    globals::gameEventSystem->PostEventAbstract(0, false, &filter, message->GetSerializableMessage(), message->GetProtobufMessage(), 0);
+    // This is for calling send in a UM hook, if calling normal send using the UM instance from the UM hook, it will cause an inifinite loop, then crashing the server
+    static void (IGameEventSystem::*PostEventAbstract)(CSplitScreenSlot, bool, IRecipientFilter*, INetworkMessageInternal*, const CNetMessage*, unsigned long) = &IGameEventSystem::PostEventAbstract;
+
+    if (message->IsManuallyAllocated())
+        globals::gameEventSystem->PostEventAbstract(0, false, &filter, message->GetSerializableMessage(), message->GetProtobufMessage(), 0);
+    else
+        SH_CALL(globals::gameEventSystem, PostEventAbstract)(0, false, &filter, message->GetSerializableMessage(), message->GetProtobufMessage(), 0);
 }
 
 static void UserMessageDelete(ScriptContext& scriptContext)