Core/Logging: Force synchronous logging after io_service shutdown - fixes logging on worldserver shutdown

(cherry picked from commit a0b2be6c1d)

src/common/Logging/Log.cpp

@@ -337,6 +337,13 @@ void Log::Initialize(boost::asio::io_service* ioService)
     LoadFromConfig();
 }
 
+void Log::SetSynchronous()
+{
+    delete _strand;
+    _strand = nullptr;
+    _ioService = nullptr;
+}
+
 void Log::LoadFromConfig()
 {
     Close();

src/common/Logging/Log.h

@@ -47,6 +47,7 @@ class Log
         static Log* instance();
 
         void Initialize(boost::asio::io_service* ioService);
+        void SetSynchronous();  // Not threadsafe - should only be called from main() after all threads are joined
         void LoadFromConfig();
         void Close();
         bool ShouldLog(std::string const& type, LogLevel level) const;

src/server/worldserver/Main.cpp

@@ -248,6 +248,8 @@ extern int main(int argc, char** argv)
     // Shutdown starts here
     ShutdownThreadPool(threadPool);
 
+    sLog->SetSynchronous();
+
     sScriptMgr->OnShutdown();
 
     sIpcContext->Close();