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

src/StoreKit/NativeMethods.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 using System.Runtime.InteropServices;
 using ObjCRuntime;

src/StoreKit/SKAdNetworkCompat.cs

@@ -7,6 +7,8 @@
 // Copyright 2018 Microsoft Corporation.
 //
 
+#nullable enable
+
 using System;
 using System.ComponentModel;
 

src/StoreKit/SKCloudServiceSetupOptions.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 #if __IOS__
 
 using System;
@@ -10,10 +12,12 @@ partial class SKCloudServiceSetupOptions {
 
 		public virtual SKCloudServiceSetupAction? Action {
 			get {
+				if (_Action is null)
+					return null;
 				return (SKCloudServiceSetupAction?) (SKCloudServiceSetupActionExtensions.GetValue (_Action));
 			}
 			set {
-				_Action = value != null ? SKCloudServiceSetupActionExtensions.GetConstant (value.Value) : null;
+				_Action = value is not null ? SKCloudServiceSetupActionExtensions.GetConstant (value.Value) : null;
 			}
 		}
 	}

src/StoreKit/SKOverlayAppClipConfiguration.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 #if __IOS__
 using System;
 
@@ -10,7 +12,7 @@ namespace StoreKit {
 #if !COREBUILD
 	public partial class SKOverlayAppClipConfiguration
 	{
-		public NSObject this[string i] {
+		public NSObject? this[string i] {
 			get => GetAdditionalValue (i); 
 			set => SetAdditionalValue (value, i);
 		}

src/StoreKit/SKOverlayAppConfiguration.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 #if __IOS__
 using System;
 
@@ -10,7 +12,7 @@ namespace StoreKit {
 #if !COREBUILD
 	public partial class SKOverlayAppConfiguration 
 	{
-		public NSObject this[string i] {
+		public NSObject? this[string i] {
 			get => GetAdditionalValue (i); 
 			set => SetAdditionalValue (value, i);
 		}

src/StoreKit/SKPayment.cs

@@ -1,5 +1,7 @@
 // Copyright 2015 Xamarin Inc.
 
+#nullable enable
+
 using System;
 
 using StoreKit;

src/StoreKit/SKPaymentTransactionObserver.cs

@@ -1,5 +1,7 @@
 // Copyright 2015-2016 Xamarin Inc.
 
+#nullable enable
+
 #if !XAMCORE_3_0
 
 using System;

src/StoreKit/SKReceiptProperty.cs

@@ -6,6 +6,9 @@
 //
 // Copyright 2013 Xamarin Inc.
 //
+
+#nullable enable
+
 using ObjCRuntime;
 using Foundation;
 using CoreFoundation;

src/StoreKit/StoreProductParameters.cs

@@ -25,6 +25,8 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
+#nullable enable
+
 #if !WATCH
 
 using System;
@@ -54,7 +56,7 @@ public int? ITunesItemIdentifier {
 			}
 		}
 
-		public string AffiliateToken {
+		public string? AffiliateToken {
 			get {
 				return GetStringValue (SKStoreProductParameterKey.AffiliateToken);
 			}
@@ -63,7 +65,7 @@ public string AffiliateToken {
 			}
 		}
 
-		public string CampaignToken {
+		public string? CampaignToken {
 			get {
 				return GetStringValue (SKStoreProductParameterKey.CampaignToken);
 			}