try not to crash when size of arrays in config file changes

BizHawk.MultiClient/ConfigService.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using System.Reflection;
 using System.Windows.Forms;
 using Newtonsoft.Json;
 
@@ -7,7 +8,7 @@ namespace BizHawk.MultiClient
 {
 	public static class ConfigService
 	{
-		public static T Load<T>(string filepath) where T : new()
+		public static T Load<T>(string filepath, T currentConfig) where T : new()
 		{
 			T config = new T();
 
@@ -22,9 +23,29 @@ namespace BizHawk.MultiClient
 						config = (T)s.Deserialize(r, typeof(T));
 					}
 			}
-            catch (Exception e) { MessageBox.Show(e.ToString()); }
+			catch (Exception e) { MessageBox.Show(e.ToString()); }
 			if (config == null) return new T();
-			else return config;
+
+			//patch up arrays in the config with the minimum number of things
+			foreach(var fi in typeof(T).GetFields(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
+				if (fi.FieldType.IsArray)
+				{
+					Array aold = fi.GetValue(currentConfig) as Array;
+					Array anew = fi.GetValue(config) as Array;
+					if (aold.Length == anew.Length) continue;
+
+					//create an array of the right size
+					Array acreate = Array.CreateInstance(fi.FieldType.GetElementType(), Math.Max(aold.Length,anew.Length));
+					
+					//copy the old values in, (presumably the defaults), and then copy the new ones on top
+					Array.Copy(aold, acreate, Math.Min(aold.Length,acreate.Length));
+					Array.Copy(anew, acreate, Math.Min(anew.Length, acreate.Length));
+					
+					//stash it into the config struct
+					fi.SetValue(config, acreate);
+				}
+					
+			return config;
 		}
 
 		public static void Save(string filepath, object config)

BizHawk.MultiClient/MainForm.MenuItems.cs

@@ -1126,7 +1126,7 @@ namespace BizHawk.MultiClient
 
 		private void loadConfigToolStripMenuItem_Click(object sender, EventArgs e)
 		{
-			Global.Config = ConfigService.Load<Config>(PathManager.DefaultIniPath);
+			Global.Config = ConfigService.Load<Config>(PathManager.DefaultIniPath, Global.Config);
 			Global.RenderPanel.AddMessage("Saved loaded");
 		}
 

BizHawk.MultiClient/Program.cs

@@ -16,7 +16,7 @@ namespace BizHawk.MultiClient
 			Application.EnableVisualStyles();
 			Application.SetCompatibleTextRenderingDefault(false);
 
-			Global.Config = ConfigService.Load<Config>(PathManager.DefaultIniPath);
+			Global.Config = ConfigService.Load<Config>(PathManager.DefaultIniPath, new Config());
 
 #if WINDOWS
 			try { Global.DSound = new DirectSound(); }