[gameplaykit] Add nullability to (generated and manual) bindings

src/GameplayKit/GKBehavior.cs

@@ -7,6 +7,8 @@
 // Copyright 2015 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 
@@ -18,7 +20,10 @@ public GKGoal this [nuint index] {
 		}
 
 		public NSNumber this [GKGoal goal] {
-			get { return ObjectForKeyedSubscript (goal); }
+			// The docs show that ObjectForKeyedSubscript should return 0.0 if the GKGoal is not
+			// available but actually returns null: https://developer.apple.com/documentation/gameplaykit/gkbehavior/1388723-objectforkeyedsubscript?language=objc
+			// radar filed here: https://feedbackassistant.apple.com/feedback/9979863
+			get { return ObjectForKeyedSubscript (goal) ?? throw new ArgumentOutOfRangeException (nameof (goal)); }
 			set { SetObject (value, goal); }
 		}
 	}

src/GameplayKit/GKCompat.cs

@@ -1,5 +1,7 @@
 // Compatibility stubs
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;

src/GameplayKit/GKComponentSystem.cs

@@ -7,6 +7,8 @@
 // Copyright 2015 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
@@ -19,7 +21,7 @@ public GKComponentSystem ()
 		{
 		}
 
-		public Type ComponentType { 
+		public Type? ComponentType { 
 			get { return Class.Lookup (ComponentClass); }
 		}
 

src/GameplayKit/GKCompositeBehavior.cs

@@ -7,13 +7,15 @@
 // Copyright 2016 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 
 namespace GameplayKit {
 	public partial class GKCompositeBehavior {
 
-		public GKBehavior this [nuint index] {
+		public new GKBehavior this [nuint index] {
 			get { return ObjectAtIndexedSubscript (index); }
 		}
 

src/GameplayKit/GKEntity.cs

@@ -7,6 +7,8 @@
 // Copyright 2015 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
@@ -19,7 +21,7 @@ public void RemoveComponent (Type componentType)
 			RemoveComponent (GKState.GetClass (componentType, "componentType"));
 		}
 
-		public GKComponent GetComponent (Type componentType)
+		public GKComponent? GetComponent (Type componentType)
 		{
 			return GetComponent (GKState.GetClass (componentType, "componentType"));
 		}

src/GameplayKit/GKGameModel.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 
 namespace GameplayKit {

src/GameplayKit/GKGridGraph.cs

@@ -7,6 +7,8 @@
 // Copyright 2016 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using ObjCRuntime;
 #if NET
@@ -19,12 +21,12 @@ namespace GameplayKit {
 	public partial class GKGridGraph {
 
 #if !NET
-		public virtual GKGridGraphNode GetNodeAt (Vector2i position)
+		public virtual GKGridGraphNode? GetNodeAt (Vector2i position)
 		{
 			return GetNodeAt<GKGridGraphNode> (position);
 		}
 #endif
-		public NodeType GetNodeAt<NodeType> (Vector2i position) where NodeType : GKGridGraphNode
+		public NodeType? GetNodeAt<NodeType> (Vector2i position) where NodeType : GKGridGraphNode
 		{
 			return Runtime.GetNSObject<NodeType> (_GetNodeAt (position));
 		}

src/GameplayKit/GKObstacleGraph.cs

@@ -7,6 +7,8 @@
 // Copyright 2016 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
@@ -54,12 +56,12 @@ public GKObstacleGraph (NSCoder coder) : base (coder)
 		{
 		}
 
-		public static GKObstacleGraph<NodeType> FromObstacles (GKPolygonObstacle [] obstacles, float bufferRadius)
+		public static new GKObstacleGraph<NodeType>? FromObstacles (GKPolygonObstacle [] obstacles, float bufferRadius)
 		{
 			return Runtime.GetNSObject <GKObstacleGraph<NodeType>> (GraphWithObstacles (obstacles, bufferRadius, new Class (typeof (NodeType))));
 		}
 
-		public NodeType [] GetNodes (GKPolygonObstacle obstacle)
+		public new NodeType [] GetNodes (GKPolygonObstacle obstacle)
 		{
 			return NSArray.ArrayFromHandle<NodeType> (_GetNodes (obstacle));
 		}

src/GameplayKit/GKPath.cs

@@ -7,6 +7,8 @@
 // Copyright 2015 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
@@ -25,8 +27,8 @@ public partial class GKPath {
 
 		public static GKPath FromPoints (Vector2[] points, float radius, bool cyclical)
 		{
-			if (points == null)
-				throw new ArgumentNullException ("points");
+			if (points is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (points));
 
 			var buffer = IntPtr.Zero;
 			try {
@@ -42,8 +44,8 @@ public static GKPath FromPoints (Vector2[] points, float radius, bool cyclical)
 		[DesignatedInitializer]
 		public GKPath (Vector2 [] points, float radius, bool cyclical)
 		{
-			if (points == null)
-				throw new ArgumentNullException ("points");
+			if (points is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (points));
 
 			var buffer = IntPtr.Zero;
 			try {
@@ -68,8 +70,8 @@ public GKPath (Vector2 [] points, float radius, bool cyclical)
 #endif
 		public static GKPath FromPoints (Vector3 [] points, float radius, bool cyclical)
 		{
-			if (points == null)
-				throw new ArgumentNullException ("points");
+			if (points is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (points));
 
 			var buffer = IntPtr.Zero;
 			try {
@@ -95,8 +97,8 @@ public static GKPath FromPoints (Vector3 [] points, float radius, bool cyclical)
 #endif
 		public GKPath (Vector3 [] points, float radius, bool cyclical)
 		{
-			if (points == null)
-				throw new ArgumentNullException ("points");
+			if (points is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (points));
 
 			var buffer = IntPtr.Zero;
 			try {

src/GameplayKit/GKPolygonObstacle.cs

@@ -7,6 +7,8 @@
 // Copyright 2015 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
@@ -22,8 +24,8 @@ public partial class GKPolygonObstacle {
 
 		public static GKPolygonObstacle FromPoints (Vector2 [] points)
 		{
-			if (points == null)
-				throw new ArgumentNullException ("points");
+			if (points is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (points));
 
 			var size = Marshal.SizeOf (typeof (Vector2));
 			var length = points.Length * size;
@@ -45,8 +47,8 @@ public static GKPolygonObstacle FromPoints (Vector2 [] points)
 
 		static unsafe IntPtr GetPointer (Vector2[] points)
 		{
-			if (points == null)
-				throw new ArgumentNullException ("points");
+			if (points is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (points));
 
 			if (ctor_pointer != IntPtr.Zero) {
 				// This can occur of a previous call to the base ctor threw an exception

src/GameplayKit/GKPrimitives.cs

@@ -7,6 +7,8 @@
 // Copyright 2016 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using System.Runtime.InteropServices;
 using ObjCRuntime;
@@ -72,8 +74,8 @@ public Vector3 [] Points {
 				return points ?? (points = new Vector3 [3]);
 			}
 			set {
-				if (value == null)
-					throw new ArgumentNullException (nameof (value));
+				if (value is null)
+					ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (value));
 				if (value.Length != 3)
 					throw new ArgumentOutOfRangeException (nameof (value), "The length of the Value array must be 3");
 				points = value;

src/GameplayKit/GKState.cs

@@ -7,6 +7,8 @@
 // Copyright 2015 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
@@ -16,8 +18,8 @@ public partial class GKState {
 
 		internal static Class GetClass (Type type, string parameterName)
 		{
-			if (type == null)
-				throw new ArgumentNullException (parameterName);
+			if (type is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (parameterName));
 
 			var klass = new Class (type);
 			// most API do not accept null so we throw in managed code instead of crashing the app
@@ -29,11 +31,11 @@ internal static Class GetClass (Type type, string parameterName)
 
 		internal static Class GetClass (NSObject instance, string parameterName)
 		{
-			if (instance == null)
-				throw new ArgumentNullException (parameterName);
+			if (instance is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (parameterName));
 
 			var klass = instance.Class; 
-			if ((klass == null) || (klass.Handle == IntPtr.Zero))
+			if ((klass is null) || (klass.Handle == IntPtr.Zero))
 				throw new ArgumentException ("Not an type exposed to ObjC", parameterName);
 
 			return klass;

src/GameplayKit/GKStateMachine.cs

@@ -7,19 +7,21 @@
 // Copyright 2015 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
 
 namespace GameplayKit {
 	public partial class GKStateMachine : NSObject {
 
-		public GKState GetState (Type stateType)
+		public GKState? GetState (Type stateType)
 		{
 			return GetState (GKState.GetClass (stateType, "stateType"));
 		}
 
-		public GKState GetState (GKState state)
+		public GKState? GetState (GKState state)
 		{
 			return GetState (GKState.GetClass (state, "state"));
 		}

src/GameplayKit/NSArray_GameplayKit.cs

@@ -7,6 +7,8 @@
 // Copyright 2016 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
@@ -28,8 +30,8 @@ public static class NSArray_GameplayKit {
 		[Export ("shuffledArrayWithRandomSource:")]
 		public static T [] GetShuffledArray<T> (this NSArray This, GKRandomSource randomSource) where T : class, INativeObject
 		{
-			if (randomSource == null)
-				throw new ArgumentNullException (nameof (randomSource));
+			if (randomSource is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (randomSource));
 			return NSArray.ArrayFromHandle<T> (Messaging.IntPtr_objc_msgSend_IntPtr (This.Handle, Selector.GetHandle ("shuffledArrayWithRandomSource:"), randomSource.Handle));
 		}
 

tests/monotouch-test/GameplayKit/GKBehaviorTests.cs

@@ -0,0 +1,42 @@
+//
+// Unit tests for GKBehavior
+//
+// Authors:
+//	TJ Lambert <TJ.Lambert@microsoft.com>
+//
+//
+// Copyright 2022 Xamarin Inc. All rights reserved.
+//
+
+#if !__WATCHOS__
+
+using System;
+using NUnit.Framework;
+
+using Foundation;
+using GameplayKit;
+
+namespace MonoTouchFixtures.GamePlayKit {
+	[TestFixture]
+	[Preserve (AllMembers = true)]
+	public class GKBehaviorTests {
+
+		[Test]
+		public void ObjectForKeyedSubscriptTest ()
+		{
+			// Create 2 GKGoals to use in the gkBehavior
+			var goal1 = GKGoal.GetGoalToReachTargetSpeed (10);
+			var goal2 = GKGoal.GetGoalToReachTargetSpeed (15);
+
+			// Create a GKGoal that will not be included in gkBehavior
+			var goal3 = GKGoal.GetGoalToReachTargetSpeed (15);
+
+			// Create a GKBehavior from those first 2 goals
+			var gkBehavior = GKBehavior.FromGoals (new GKGoal [] { goal1, goal2 });
+
+			// Searching the gkBehavior for a non-exisitant goal should throw an ArgumentOutOfRangeException
+			Assert.Throws<ArgumentOutOfRangeException> ( () => { _ = gkBehavior[goal3]; }, "The ObjectForKeyedSubscript indexer should throw ArgumentOutOfRangeException if the goal is not in the behavior's list of GKGoals.");
+		}
+	}
+}
+#endif