Patch for https://bugzilla.xamarin.com/show_bug.cgi?id=24402

XamarinPatch-24402.cs

using System;
using Mono.Cecil;
using System.Linq;
using Mono.Cecil.Cil;
using System.IO;

namespace XamarinPatch
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			//const string path = "../../../../../PoSDB-Xamarin//packages/Xamarin.Forms.1.4.4.6392/lib/MonoAndroid10/Xamarin.Forms.Core.dll";

			string[] files = Directory.GetFiles (@"../../../../../", "Xamarin.Forms.Core.dll", SearchOption.AllDirectories);
			foreach (string file in files) {
				patchXamarinFormsCoreDll (file);
			}
		}

		static void patchXamarinFormsCoreDll (string path)
		{
			var assembly = AssemblyDefinition.ReadAssembly (path);
			ModuleDefinition module = assembly.MainModule;
			TypeDefinition mainClass = module.GetType ("Xamarin.Forms.AnimationExtensions");
			MethodDefinition method = mainClass.Methods.Single (m => m.Name == "HandleTweenerUpdated");

			Console.WriteLine ("ExceptionHandlers.Count: " + method.Body.ExceptionHandlers.Count);
			if (method.Body.ExceptionHandlers.Count == 0) {

				var il = method.Body.GetILProcessor ();

				var write = il.Create (OpCodes.Call, module.Import (typeof(Console).GetMethod ("WriteLine", new [] { typeof(object) })));
				var ret = il.Create (OpCodes.Ret);
				var leave = il.Create (OpCodes.Leave, ret);

				il.InsertAfter (method.Body.Instructions.Last (), write);
				il.InsertAfter (write, leave);
				il.InsertAfter (leave, ret);

				var handler = new ExceptionHandler (ExceptionHandlerType.Catch) {
					TryStart = method.Body.Instructions.First (),
					TryEnd = write,
					HandlerStart = write,
					HandlerEnd = ret,
					CatchType = module.Import (typeof(Exception)),
				};

				method.Body.ExceptionHandlers.Add (handler);

				string pathPatched = path + ".patched.dll";
				assembly.Write (pathPatched);
				System.IO.File.Copy (pathPatched, path, true);
			}
		}
	}
}