Avoid performing emergency network save more than once

src/network/network_client.cpp

@@ -136,6 +136,7 @@ void ClientNetworkEmergencySave()
 {
 	if (!_settings_client.gui.autosave_on_network_disconnect) return;
 	if (!_networking) return;
+	if (!ClientNetworkGameSocketHandler::EmergencySavePossible()) return;
 
 	const char *filename = "netsave.sav";
 	DEBUG(net, 0, "Client: Performing emergency save (%s)", filename);
@@ -344,6 +345,14 @@ void ClientNetworkGameSocketHandler::ClientError(NetworkRecvStatus res)
 	return true;
 }
 
+/* static */ bool ClientNetworkGameSocketHandler::EmergencySavePossible()
+{
+	if (!my_client) return false;
+	if (my_client->emergency_save_done) return false;
+	my_client->emergency_save_done = true;
+	return true;
+}
+
 
 /** Our client's connection. */
 ClientNetworkGameSocketHandler * ClientNetworkGameSocketHandler::my_client = nullptr;

src/network/network_client.h

@@ -40,6 +40,7 @@ private:
 
 	FILE *desync_log_file = nullptr;
 	std::string server_desync_log;
+	bool emergency_save_done = false;
 
 protected:
 	friend void NetworkExecuteLocalCommandQueue();
@@ -111,6 +112,8 @@ public:
 	static void Send();
 	static bool Receive();
 	static bool GameLoop();
+
+	static bool EmergencySavePossible();
 };
 
 /** Helper to make the code look somewhat nicer. */