When clearing lua callbacks, handle the case that input callbacks might not be implemented, also handle memory callbacks in a more consistent way

BizHawk.Client.Common/lua/LuaFunctionList.cs

@@ -33,22 +33,15 @@ namespace BizHawk.Client.Common
 
 		public void ClearAll()
 		{
-			if (Global.Emulator.CanPollInput())
+			if (Global.Emulator.InputCallbacksAvailable())
 			{
 				Global.Emulator.AsInputPollable().InputCallbacks.RemoveAll(this.Select(x => x.Callback));
 			}
 
-			if (Global.Emulator.CanDebug())
+			if (Global.Emulator.MemoryCallbacksAvailable())
 			{
-				try
-				{
-					var cbSys = Global.Emulator.AsDebuggable().MemoryCallbacks;
-					cbSys.RemoveAll(this.Select(x => x.Callback));
-				}
-				catch
-				{
-					//swallow exceptions here. many cores havent implemented memorycallbacks, we ought to have more granular feature querying
-				}
+				var cbSys = Global.Emulator.AsDebuggable().MemoryCallbacks;
+				cbSys.RemoveAll(this.Select(x => x.Callback));
 			}
 
 			Clear();

BizHawk.Emulation.Common/Extensions.cs

@@ -78,6 +78,31 @@ namespace BizHawk.Emulation.Common.IEmulatorExtensions
 			return (IInputPollable)core.ServiceProvider.GetService<IInputPollable>();
 		}
 
+		public static bool InputCallbacksAvailable(this IEmulator core)
+		{
+			if (core == null)
+			{
+				return false;
+			}
+
+			// TODO: this is a pretty ugly way to handle this
+			var pollable = (IInputPollable)core.ServiceProvider.GetService<IInputPollable>();
+			if (pollable != null)
+			{
+				try
+				{
+					var callbacks = pollable.InputCallbacks;
+					return true;
+				}
+				catch (NotImplementedException)
+				{
+					return false;
+				}
+			}
+
+			return false;
+		}
+
 		public static bool HasDriveLight(this IEmulator core)
 		{
 			if (core == null)