[Generator] BindAs attribute for smart enums of an array of nullable values generates code that doesn't compile, Fixes bug 57797 (#2954)

* [Generator] BindAs attribute for smart enums of an array of nullable values generates code that doesn't compile, Fixes bug 57797

https://bugzilla.xamarin.com/show_bug.cgi?id=57797

We now correctly compiles the array nullabe types

* Disable Nullable array types in BindAs until we add registrar support

src/generator.cs

@@ -1307,13 +1307,13 @@ public partial class Generator : IMemberGatherer {
 			var arrRetType = TypeManager.GetUnderlyingNullableType (retType.GetElementType ()) ?? retType.GetElementType ();
 			var valueConverter = string.Empty;
 
-			if (arrType == TypeManager.NSString) {
+			if (arrType == TypeManager.NSString && !isNullable) {
 				valueConverter = isNullable ? "o == null ? null : " : string.Empty;
-				valueConverter += $"{FormatType (retType.DeclaringType, arrRetType)}Extensions.GetConstant (o), {parameterName});";
+				valueConverter += $"{FormatType (retType.DeclaringType, arrRetType)}Extensions.GetConstant ({(isNullable ? "o.Value" : "o")}), {parameterName});";
-			} else if (arrType == TypeManager.NSNumber) {
+			} else if (arrType == TypeManager.NSNumber && !isNullable) {
 				var cast = arrRetType.IsEnum ? "(int)" : string.Empty;
 				valueConverter = $"new NSNumber ({cast}o{denullify}), {parameterName});";
-			} else if (arrType == TypeManager.NSValue) {
+			} else if (arrType == TypeManager.NSValue && !isNullable) {
 				var typeStr = string.Empty;
 				if (!NSValueCreateMap.TryGetValue (arrRetType, out typeStr)) {
 					if (arrRetType.Name == "RectangleF" || arrRetType.Name == "SizeF" || arrRetType.Name == "PointF")
@@ -1323,7 +1323,7 @@ public partial class Generator : IMemberGatherer {
 				}
 				valueConverter = $"NSValue.From{typeStr} (o{denullify}), {parameterName});";
 			} else
-				throw new BindingException (1048, true, "Unsupported type {0} decorated with [BindAs]", retType.Name);
+				throw new BindingException (1048, true, "Unsupported type {0} decorated with [BindAs]", isNullable ? arrRetType.Name + "?[]" : retType.Name);
 			temp = $"NSArray.FromNSObjects (o => {valueConverter}";
 		} else
 			throw new BindingException (1048, true, "Unsupported type {0} decorated with [BindAs]", retType.Name);
@@ -1449,16 +1449,16 @@ public partial class Generator : IMemberGatherer {
 			var arrIsNullable = nullableElementType != null;
 			var arrRetType = arrIsNullable ? nullableElementType : retType.GetElementType ();
 			var valueFetcher = string.Empty;
-			if (arrType == TypeManager.NSString)
+			if (arrType == TypeManager.NSString && !arrIsNullable)
 				append = $"ptr => {{\n\tusing (var str = Runtime.GetNSObject<NSString> (ptr)) {{\n\t\treturn {FormatType (arrRetType.DeclaringType, arrRetType)}Extensions.GetValue (str);\n\t}}\n}}";
-			else if (arrType == TypeManager.NSNumber) {
+			else if (arrType == TypeManager.NSNumber && !arrIsNullable) {
 				if (NSNumberReturnMap.TryGetValue (arrRetType, out valueFetcher) || arrRetType.IsEnum) {
 					var getterStr = string.Format ("{0}{1}", arrIsNullable ? "?" : string.Empty, arrRetType.IsEnum ? ".Int32Value" : valueFetcher);
 					append = string.Format ("ptr => {{\n\tusing (var num = Runtime.GetNSObject<NSNumber> (ptr)) {{\n\t\treturn ({1}) num{0};\n\t}}\n}}", getterStr, FormatType (arrRetType.DeclaringType, arrRetType));
 				}
 				else
 					throw new BindingException (1049, true, GetBindAsExceptionString ("unbox", retType.Name, arrType.Name, "array", minfo.mi));
-			} else if (arrType == TypeManager.NSValue) {
+			} else if (arrType == TypeManager.NSValue && !arrIsNullable) {
 				if (arrRetType.Name == "RectangleF" || arrRetType.Name == "SizeF" || arrRetType.Name == "PointF")
 					valueFetcher = $"{(arrIsNullable ? "?" : string.Empty)}.{arrRetType.Name}Value";
 				else if (!NSValueReturnMap.TryGetValue (arrRetType, out valueFetcher))
@@ -1466,7 +1466,7 @@ public partial class Generator : IMemberGatherer {
 
 				append = string.Format ("ptr => {{\n\tusing (var val = Runtime.GetNSObject<NSValue> (ptr)) {{\n\t\treturn val{0};\n\t}}\n}}", valueFetcher);
 			} else
-				throw new BindingException (1048, true, "Unsupported type {0} decorated with [BindAs]", retType.Name);
+				throw new BindingException (1048, true, "Unsupported type {0} decorated with [BindAs]", arrIsNullable ? arrRetType.Name + "?[]" : retType.Name);
 		} else
 			throw new BindingException (1048, true, "Unsupported type {0} decorated with [BindAs]", retType.Name);
 		return append;

tests/generator/BGenTool.cs

@@ -23,6 +23,7 @@ namespace Xamarin.Tests
 	class BGenTool : Tool
 	{
 		public Profile Profile;
+		public bool ProcessEnums;
 
 		public List<string> ApiDefinitions = new List<string> ();
 		public string TmpDirectory;
@@ -73,6 +74,9 @@ namespace Xamarin.Tests
 			if (!string.IsNullOrEmpty (TmpDirectory))
 				sb.Append (" --tmpdir=").Append (StringUtils.Quote (TmpDirectory));
 
+			if (ProcessEnums)
+				sb.Append (" --process-enums");
+
 			return sb.ToString ();
 		}
 

tests/generator/ErrorTests.cs

@@ -71,5 +71,99 @@ namespace Bug57795Tests {
 			bgen.AssertExecuteError ("build");
 			bgen.AssertError (1048, "Unsupported type AVMediaTypes[,] decorated with [BindAs]");
 		}
+
+		[Test]
+		public void BindAsNullableNSStringArrayError ()
+		{
+			// https://bugzilla.xamarin.com/show_bug.cgi?id=57797
+
+			var bgen = new BGenTool {
+				Profile = Profile.iOS
+			};
+			bgen.CreateTemporaryBinding (@"
+using System;
+using Foundation;
+using ObjCRuntime;
+using AVFoundation;
+using CoreAnimation;
+
+namespace Bug57797Tests {
+
+	[BaseType (typeof (NSObject))]
+	interface FooObject {
+
+		[BindAs (typeof (AVMediaTypes? []))]
+		[Export (""strongNullableAVMediaTypesProperties"")]
+		NSString [] StrongNullableAVMediaTypesProperties { get; set; }
+	}
+}");
+			bgen.AssertExecuteError ("build");
+			bgen.AssertError (1048, "Unsupported type AVMediaTypes?[] decorated with [BindAs]");
+		}
+
+		[Test]
+		public void BindAsNullableNSValueArrayError ()
+		{
+			// https://bugzilla.xamarin.com/show_bug.cgi?id=57797
+
+			var bgen = new BGenTool {
+				Profile = Profile.iOS
+			};
+			bgen.CreateTemporaryBinding (@"
+using System;
+using Foundation;
+using ObjCRuntime;
+using AVFoundation;
+using CoreAnimation;
+
+namespace Bug57797Tests {
+
+	[BaseType (typeof (NSObject))]
+	interface FooObject {
+
+		[BindAs (typeof (CATransform3D? []))]
+		[Export (""PCATransform3DNullableArray"")]
+		NSValue [] PCATransform3DNullableArrayValue { get; set; }
+	}
+}");
+			bgen.AssertExecuteError ("build");
+			bgen.AssertError (1048, "Unsupported type CATransform3D?[] decorated with [BindAs]");
+		}
+
+		[Test]
+		public void BindAsNullableNSNumberArrayError ()
+		{
+			// https://bugzilla.xamarin.com/show_bug.cgi?id=57797
+
+			var bgen = new BGenTool {
+				Profile = Profile.iOS,
+				ProcessEnums = true
+			};
+			bgen.CreateTemporaryBinding (@"
+using System;
+using Foundation;
+using ObjCRuntime;
+using AVFoundation;
+using CoreAnimation;
+
+namespace Bug57797Tests {
+
+	[Native]
+	enum Foo : long {
+		One,
+		Two
+	}
+
+	[BaseType (typeof (NSObject))]
+	interface FooObject {
+
+		[BindAs (typeof (Foo? []))]
+		[Export (""strongNullableAVMediaTypesProperties"")]
+		NSNumber[] StrongNullableFoo { get; set; }
+	}
+}");
+			bgen.AssertExecuteError ("build");
+			bgen.AssertError (1048, "Unsupported type Foo?[] decorated with [BindAs]");
+		}
 	}
 }