[Xamarin.Android.Tools.Bytecode] Kotlin unsigned internal props (#1156)

Context: 6bd7ae4

In commit 6bd7ae4, we updated the logic that matches a Kotlin public
property getter/setter to a generated Java getter/setter that follows
this pattern:

	// Kotlin
	public var type = 0

	// Java
	private int type = 0;

	public int getType () { ... }
	public void setType (int p0) { ... }

However, this caused unit tests in xamarin/xamarin-android to fail
that when using Kotlin unsigned types:

	KotlinUnsignedTypesTests.cs: 
	error CS0200: Property or indexer 'UnsignedInstanceMethods.UnsignedInstanceProperty' cannot be assigned to -- it is read only

This is because properties that use Kotlin unsigned types append a
`-<type-hash>` suffix to their getter/setter names:

	// Kotlin
	public var type: UInt = 0u

	// Java
	private int type = 0;

	public int getType-pVg5ArA () { ... }
	public void setType-WZ4Q5Ns (int p0) { ... }

Update our Kotlin logic to handle this case.

src/Xamarin.Android.Tools.Bytecode/Kotlin/KotlinFixups.cs

@@ -389,10 +389,12 @@ static void FixupField (FieldInfo? field, KotlinProperty metadata)
 				return null;
 
 			// Public/protected getters look like "getFoo"
+			// Public/protected getters with unsigned types look like "getFoo-abcdefg"
 			// Internal getters look like "getFoo$main"
+			// Internal getters with unsigned types look like "getFoo-WZ4Q5Ns$main"
 			var possible_methods = property.IsInternalVisibility ?
-				klass.Methods.Where (method => method.Name.StartsWith ($"get{property.Name.Capitalize ()}$", StringComparison.Ordinal)) :
-				klass.Methods.Where (method => method.Name.Equals ($"get{property.Name.Capitalize ()}", StringComparison.Ordinal));
+				klass.Methods.Where (method => method.GetMethodNameWithoutUnsignedSuffix ().StartsWith ($"get{property.Name.Capitalize ()}$", StringComparison.Ordinal)) :
+				klass.Methods.Where (method => method.GetMethodNameWithoutUnsignedSuffix ().Equals ($"get{property.Name.Capitalize ()}", StringComparison.Ordinal));
 
 			possible_methods = possible_methods.Where (method =>
 					method.GetParameters ().Length == 0 &&
@@ -409,10 +411,12 @@ static void FixupField (FieldInfo? field, KotlinProperty metadata)
 				return null;
 
 			// Public/protected setters look like "setFoo"
+			// Public/protected setters with unsigned types look like "setFoo-abcdefg"
 			// Internal setters look like "setFoo$main"
+			// Internal setters with unsigned types look like "setFoo-WZ4Q5Ns$main"
 			var possible_methods = property.IsInternalVisibility ?
-				klass.Methods.Where (method => method.Name.StartsWith ($"set{property.Name.Capitalize ()}$", StringComparison.Ordinal)) :
-				klass.Methods.Where (method => method.Name.Equals ($"set{property.Name.Capitalize ()}", StringComparison.Ordinal));
+				klass.Methods.Where (method => method.GetMethodNameWithoutUnsignedSuffix ().StartsWith ($"set{property.Name.Capitalize ()}$", StringComparison.Ordinal)) :
+				klass.Methods.Where (method => method.GetMethodNameWithoutUnsignedSuffix ().Equals ($"set{property.Name.Capitalize ()}", StringComparison.Ordinal));
 
 			possible_methods = possible_methods.Where (method => 
 						property.ReturnType != null &&

src/Xamarin.Android.Tools.Bytecode/Kotlin/KotlinUtilities.cs

@@ -76,16 +76,23 @@ public static ParameterInfo[] GetFilteredParameters (this MethodInfo method)
 			return method.GetParameters ().Where (p => p.Type.BinaryName != "Lkotlin/jvm/internal/DefaultConstructorMarker;" && !p.Name.StartsWith ("$", StringComparison.Ordinal)).ToArray ();
 		}
 
-		public static string GetMethodNameWithoutSuffix (this MethodInfo method)
+		public static string GetMethodNameWithoutUnsignedSuffix (this MethodInfo method)
+			=> GetMethodNameWithoutUnsignedSuffix (method.Name);
+
+		public static string GetMethodNameWithoutUnsignedSuffix (string name)
 		{
-			// Kotlin will rename some of its constructs to hide them from the Java runtime
-			// These take the form of thing like:
-			// - add-impl
+			// Kotlin will add a type hash suffix to the end of the method name that use unsigned types
 			// - add-H3FcsT8
 			// We strip them for trying to match up the metadata to the MethodInfo
-			var index = method.Name.IndexOfAny (new [] { '-', '$' });
+			// Additionally, generated setters for unsigned types have multiple suffixes,
+			// we only want to remove the unsigned suffix.
+			// - getFoo-pVg5ArA$main
+			var dollar_index = name.IndexOf ('$');
+			var dollar_suffix = dollar_index >= 0 ? name.Substring (dollar_index) : string.Empty;
+
+			var index = name.IndexOf ('-');
 
-			return index >= 0 ? method.Name.Substring (0, index) : method.Name;
+			return index >= 0 ? name.Substring (0, index) + dollar_suffix : name;
 		}
 
 		public static bool IsDefaultConstructorMarker (this MethodInfo method)

tests/Xamarin.Android.Tools.Bytecode-Tests/KotlinFixupsTests.cs

@@ -347,6 +347,17 @@ public void HandleKotlinNameShadowing ()
 			Assert.False (klass.Methods.Single (m => m.Name == "getItype2$main").AccessFlags.HasFlag (MethodAccessFlags.Public));
 			Assert.True (klass.Methods.Single (m => m.Name == "getItype2").AccessFlags.HasFlag (MethodAccessFlags.Public));
 			Assert.True (klass.Methods.Single (m => m.Name == "setItype2").AccessFlags.HasFlag (MethodAccessFlags.Public));
+
+			// Internal property with unsigned type
+			// Generated getter/setter should not be public
+			Assert.False (klass.Methods.Single (m => m.Name == "getUnsignedInternalProperty-pVg5ArA$main").AccessFlags.HasFlag (MethodAccessFlags.Public));
+			Assert.False (klass.Methods.Single (m => m.Name == "setUnsignedInternalProperty-WZ4Q5Ns$main").AccessFlags.HasFlag (MethodAccessFlags.Public));
+
+			// Public property with unsigned type
+			// We want to check that KotlinType/KotlinReturnType are filled it as it proves our FindJavaProperty[Getter|Setter] functions are matching
+			// (We aren't changing the visibility of the getter/setter, so we can't just check the access flags)
+			Assert.AreEqual ("uint", klass.Methods.Single (m => m.Name == "getUnsignedPublicProperty-pVg5ArA").KotlinReturnType);
+			Assert.AreEqual ("uint", klass.Methods.Single (m => m.Name == "setUnsignedPublicProperty-WZ4Q5Ns").GetParameters () [0].KotlinType);
 		}
 
 		[Test]
@@ -418,5 +429,15 @@ public void MatchMetadataToMultipleMethodsWithSameMangledName ()
 			Assert.AreEqual ("ubyte", java_methods.ElementAt (0).GetParameters ().Single (p => p.Name == "element").KotlinType);
 			Assert.AreEqual ("ubyte", java_methods.ElementAt (1).GetParameters ().Single (p => p.Name == "element").KotlinType);
 		}
+
+		[Test]
+		public void GetMethodNameWithoutUnsignedSuffix ()
+		{
+			// Just a few quick tests to ensure the various cases are covered
+			Assert.AreEqual ("setFoo", KotlinUtilities.GetMethodNameWithoutUnsignedSuffix ("setFoo"));
+			Assert.AreEqual ("setFoo", KotlinUtilities.GetMethodNameWithoutUnsignedSuffix ("setFoo-7apg3OU"));
+			Assert.AreEqual ("setFoo$main", KotlinUtilities.GetMethodNameWithoutUnsignedSuffix ("setFoo-7apg3OU$main"));
+			Assert.AreEqual ("setFoo$main", KotlinUtilities.GetMethodNameWithoutUnsignedSuffix ("setFoo$main"));
+		}
 	}
 }

tests/Xamarin.Android.Tools.Bytecode-Tests/kotlin/NameShadowing.kt

@@ -27,4 +27,8 @@ public class NameShadowing {
 	internal val itype2 = 0
 	fun getItype2(): Int = itype2
 	fun setItype2(type: Int) { }
+
+	// Unsigned types properties
+    internal var unsignedInternalProperty: UInt = 3u
+    var unsignedPublicProperty: UInt = 3u
 }