[TrimmableTypeMap] Remove ForceUnconditionalEntries workaround

src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/ModelBuilder.cs

@@ -16,13 +16,6 @@ static class ModelBuilder
 {
 	const string ProxyTypeSuffix = "_Proxy";
 
-	// Workaround for https://github.com/dotnet/runtime/issues/127004
-	// When true, all TypeMap entries are emitted as 2-arg (unconditional) to avoid the
-	// trimmer bug that strips TypeMapAssociation attributes when a TypeMap attribute
-	// references the same type. Set to false once the runtime bug is fixed to re-enable
-	// 3-arg conditional entries that allow unused framework bindings to be trimmed away.
-	const bool ForceUnconditionalEntries = true;
-
 	static readonly HashSet<string> EssentialRuntimeTypes = new (StringComparer.Ordinal) {
 		"java/lang/Object",
 		"java/lang/Class",
@@ -189,13 +182,7 @@ static void EmitPeers (TypeMapAssemblyData model, string jniName,
 		}
 
 		// Base JNI name entry → alias holder (self-referencing trim target, kept alive by associations)
-		// When ForceUnconditionalEntries is true we MUST emit this as 2-arg (unconditional) just
-		// like BuildEntry does: dotnet/runtime#127004 strips the TypeMapAssociation that keeps the
-		// holder alive when a TypeMap entry references the same type, leaving the dictionary key
-		// missing at runtime and breaking hierarchy lookups for essential types like
-		// java/lang/String and java/lang/Object.
-		bool aliasBaseUnconditional = ForceUnconditionalEntries
-			|| EssentialRuntimeTypes.Contains (jniName)
+		bool aliasBaseUnconditional = EssentialRuntimeTypes.Contains (jniName)
 			|| peersForName.Any (IsUnconditionalEntry);
 		model.Entries.Add (new TypeMapAttributeData {
 			JniName = jniName,
@@ -406,9 +393,7 @@ static TypeMapAttributeData BuildEntry (JavaPeerInfo peer, JavaPeerProxyData? pr
 			proxyRef = AssemblyQualify (peer.ManagedTypeName, peer.AssemblyName);
 		}
 
-		// When ForceUnconditionalEntries is true, always emit 2-arg (unconditional) TypeMap
-		// attributes to work around https://github.com/dotnet/runtime/issues/127004.
-		bool isUnconditional = ForceUnconditionalEntries || IsUnconditionalEntry (peer);
+		bool isUnconditional = IsUnconditionalEntry (peer);
 		string? targetRef = null;
 		if (!isUnconditional) {
 			targetRef = AssemblyQualify (peer.ManagedTypeName, peer.AssemblyName);

src/Mono.Android/Microsoft.Android.Runtime/TrimmableTypeMap.cs

@@ -23,6 +23,7 @@ public class TrimmableTypeMap
 	static readonly JavaPeerProxy s_noPeerSentinel = new MissingJavaPeerProxy ();
 	static TrimmableTypeMap? s_instance;
 	static bool s_nativeMethodsRegistered;
+	static JniMethodInfo? s_classGetInterfacesMethod;
 
 	internal static TrimmableTypeMap Instance =>
 		s_instance ?? throw new InvalidOperationException (
@@ -31,6 +32,7 @@ public class TrimmableTypeMap
 	readonly ITypeMap _typeMap;
 	readonly ConcurrentDictionary<Type, JavaPeerProxy> _proxyCache = new ();
 	readonly ConcurrentDictionary<string, JavaPeerProxy[]> _jniProxyCache = new (StringComparer.Ordinal);
+	readonly ConcurrentDictionary<(string ClassName, Type TargetType), JavaPeerProxy> _interfaceProxyCache = new ();
 
 	TrimmableTypeMap (ITypeMap typeMap)
 	{
@@ -255,6 +257,19 @@ internal bool TryGetJniNameForManagedType (Type managedType, [NotNullWhen (true)
 						}
 					}
 
+					// When targetType is an interface, also check the Java interfaces
+					// at each level. getInterfaces() only returns directly declared
+					// interfaces so we must call it at each class in the hierarchy.
+					// This handles the case where an intermediate class entry (e.g.,
+					// X509ExtendedTrustManager) was trimmed but the Java interface
+					// entry (e.g., X509TrustManager) survives.
+					if (targetType is { IsInterface: true } && className != null) {
+						var result = GetProxyForJavaInterfaces (self, jniClass, className, targetType);
+						if (result != null) {
+							return result;
+						}
+					}
+
 					var super = JniEnvironment.Types.GetSuperclass (jniClass);
 					JniObjectReference.Dispose (ref jniClass);
 					jniClass = super;
@@ -266,6 +281,70 @@ internal bool TryGetJniNameForManagedType (Type managedType, [NotNullWhen (true)
 			return null;
 		}
 
+		static JavaPeerProxy? GetProxyForJavaInterfaces (TrimmableTypeMap self, JniObjectReference jniClass, string className, Type targetType)
+		{
+			var proxy = self._interfaceProxyCache.GetOrAdd (
+				(className, targetType),
+				_ => TryMatchInterfaces (self, jniClass, targetType) ?? s_noPeerSentinel);
+			return ReferenceEquals (proxy, s_noPeerSentinel) ? null : proxy;
+		}
+
+		// getInterfaces() returns only directly declared interfaces (not transitive),
+		// so we recurse into super-interfaces to find the matching TypeMap entry.
+		static JavaPeerProxy? TryMatchInterfaces (TrimmableTypeMap self, JniObjectReference jniClass, Type targetType)
+		{
+			var interfaces = JniEnvironment.InstanceMethods.CallObjectMethod (jniClass, GetClassGetInterfacesMethod ());
+			try {
+				if (!interfaces.IsValid) {
+					return null;
+				}
+
+				int count = JniEnvironment.Arrays.GetArrayLength (interfaces);
+				for (int i = 0; i < count; i++) {
+					var iface = JniEnvironment.Arrays.GetObjectArrayElement (interfaces, i);
+					try {
+						var ifaceName = JniEnvironment.Types.GetJniTypeNameFromClass (iface);
+						if (ifaceName != null) {
+							var proxy = self.GetProxyForJniClass (ifaceName, targetType);
+							if (proxy != null && TargetTypeMatches (targetType, proxy.TargetType)) {
+								return proxy;
+							}
+						}
+
+						// Recurse into super-interfaces
+						var result = TryMatchInterfaces (self, iface, targetType);
+						if (result != null) {
+							return result;
+						}
+					} finally {
+						JniObjectReference.Dispose (ref iface);
+					}
+				}
+			} finally {
+				JniObjectReference.Dispose (ref interfaces);
+			}
+
+			return null;
+		}
+
+		static JniMethodInfo GetClassGetInterfacesMethod ()
+		{
+			var method = s_classGetInterfacesMethod;
+			if (method != null) {
+				return method;
+			}
+
+			var classClass = JniEnvironment.Types.FindClass ("java/lang/Class");
+			try {
+				method = JniEnvironment.InstanceMethods.GetMethodID (classClass, "getInterfaces", "()[Ljava/lang/Class;");
+			} finally {
+				JniObjectReference.Dispose (ref classClass);
+			}
+
+			var previous = Interlocked.CompareExchange (ref s_classGetInterfacesMethod, method, null);
+			return previous ?? method;
+		}
+
 		static JavaPeerProxy? TryGetProxyFromTargetType (TrimmableTypeMap self, IntPtr handle, Type? targetType)
 		{
 			if (targetType is null) {
@@ -316,16 +395,11 @@ internal bool TryGetJniNameForManagedType (Type managedType, [NotNullWhen (true)
 	/// closed subclasses of an open generic class peer.
 	/// </summary>
 	/// <remarks>
-	/// Implementers of an open generic <em>interface</em> peer are intentionally
-	/// not matched here: <see cref="TryGetProxyFromHierarchy"/> walks only the
-	/// JNI class chain (<c>getSuperclass</c>), never JNI interfaces, so the
-	/// proxy returned from that walk is always a class peer. Matching on
-	/// <c>Type.GetInterfaces()</c> would also force a trimmer
+	/// Open generic <em>interface</em> peers are intentionally not matched here:
+	/// matching on <c>Type.GetInterfaces()</c> would force a trimmer
 	/// <c>DynamicallyAccessedMembers(Interfaces)</c> annotation up the chain
-	/// (ultimately into Java.Interop's <c>CreatePeer</c> API). If we ever need
-	/// to discover interface peers, the generator should emit an explicit
-	/// implementer→interface map so runtime can avoid reflection over
-	/// interface lists.
+	/// (ultimately into Java.Interop's <c>CreatePeer</c> API). Interface peer
+	/// discovery is handled from the Java class metadata instead.
 	/// </remarks>
 	internal static bool TargetTypeMatches (Type targetType, Type proxyTargetType)
 	{

src/Mono.Android/Xamarin.Android.Net/ServerCertificateCustomValidator.cs

@@ -180,25 +180,9 @@ private static IX509TrustManager FindX509TrustManager(ITrustManager[] trustManag
 					index = i;
 					return x509TrustManager;
 				}
-
-				// On API 21-23, the default Java trust manager is TrustManagerImpl from Conscrypt. The class implements X509TrustManager
-				// but the .NET pattern matching will fail in this case and we need to cast it explicitly.
-				int apiLevel = (int)Build.VERSION.SdkInt;
-				if (apiLevel <= 23) {
-					if (IsTrustManagerImpl (trustManager)) {
-						index = i;
-						return trustManager.JavaCast<IX509TrustManager> ();
-					}
-				}
 			}
 
 			throw new InvalidOperationException($"Could not find {nameof(IX509TrustManager)} in {nameof(ITrustManager)} array.");
-
-			static bool IsTrustManagerImpl (ITrustManager trustManager)
-			{
-				var javaClassName = JNIEnv.GetClassNameFromInstance (trustManager.Handle);
-				return javaClassName.Equals ("com/android/org/conscrypt/TrustManagerImpl", StringComparison.Ordinal);
-			}
 		}
 
 		private static ITrustManager[] ModifyTrustManagersArray (ITrustManager[] trustManagers, int originalTrustManagerIndex, IX509TrustManager replacement)

src/Mono.Android/map.csv

@@ -478,9 +478,9 @@ E,36,android/app/appfunctions/AppFunctionException.ERROR_ENTERPRISE_POLICY_DISAL
 E,36,android/app/appfunctions/AppFunctionException.ERROR_FUNCTION_NOT_FOUND,1003,Android.App.AppFunctions.AppFunctionError,FunctionNotFound,remove,
 E,36,android/app/appfunctions/AppFunctionException.ERROR_INVALID_ARGUMENT,1001,Android.App.AppFunctions.AppFunctionError,InvalidArgument,remove,
 E,36,android/app/appfunctions/AppFunctionException.ERROR_SYSTEM_ERROR,2000,Android.App.AppFunctions.AppFunctionError,SystemError,remove,
-E,36,android/app/appfunctions/AppFunctionManager.APP_FUNCTION_STATE_DEFAULT,0,Android.App.AppFunctions.AppFunctionState,Default,remove,
-E,36,android/app/appfunctions/AppFunctionManager.APP_FUNCTION_STATE_DISABLED,2,Android.App.AppFunctions.AppFunctionState,Disabled,remove,
-E,36,android/app/appfunctions/AppFunctionManager.APP_FUNCTION_STATE_ENABLED,1,Android.App.AppFunctions.AppFunctionState,Enabled,remove,
+E,36,android/app/appfunctions/AppFunctionManager.APP_FUNCTION_STATE_DEFAULT,0,Android.App.AppFunctions.AppFunctionEnabledState,Default,remove,
+E,36,android/app/appfunctions/AppFunctionManager.APP_FUNCTION_STATE_DISABLED,2,Android.App.AppFunctions.AppFunctionEnabledState,Disabled,remove,
+E,36,android/app/appfunctions/AppFunctionManager.APP_FUNCTION_STATE_ENABLED,1,Android.App.AppFunctions.AppFunctionEnabledState,Enabled,remove,
 E,37,android/app/appfunctions/AppFunctionMetadata.SCOPE_ACTIVITY,1,Android.App.AppFunctions.AppFunctionMetadataScope,Activity,remove,
 E,37,android/app/appfunctions/AppFunctionMetadata.SCOPE_GLOBAL,0,Android.App.AppFunctions.AppFunctionMetadataScope,Global,remove,
 E,37,android/app/AppInteractionAttribution.INTERACTION_TYPE_OTHER,0,Android.App.AppInteractionAttributionInteractionType,Other,remove,

src/Mono.Android/methodmap.csv

@@ -4100,7 +4100,7 @@
 36,android.app.appfunctions,AppFunctionException,getErrorCategory,return,Android.App.AppFunctions.AppFunctionErrorCategory
 36,android.app.appfunctions,AppFunctionException,getErrorCode,return,Android.App.AppFunctions.AppFunctionError
 36,android.app.appfunctions,AppFunctionException,writeToParcel,flags,Android.OS.ParcelableWriteFlags
-36,android.app.appfunctions,AppFunctionManager,setAppFunctionEnabled,newEnabledState,Android.App.AppFunctions.AppFunctionState
+36,android.app.appfunctions,AppFunctionManager,setAppFunctionEnabled,newEnabledState,Android.App.AppFunctions.AppFunctionEnabledState
 36,android.app.appfunctions,ExecuteAppFunctionRequest,writeToParcel,flags,Android.OS.ParcelableWriteFlags
 36,android.app.appfunctions,ExecuteAppFunctionResponse,writeToParcel,flags,Android.OS.ParcelableWriteFlags
 36,android.app,ApplicationStartInfo,getStartComponent,return,Android.App.ApplicationStartInfoStartComponent

tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Generator/TypeMapModelBuilderTests.cs

@@ -135,6 +135,54 @@ public void Build_AliasWithMixedActivation_PrimaryNoActivation_AliasHasActivatio
 			// Both peers get associations to alias holder
 			Assert.Equal (2, model.Associations.Count);
 		}
+
+		[Fact]
+		public void Build_AllMcwAliasGroup_BaseEntryIsConditional ()
+		{
+			// When all peers in an alias group are MCW bindings (trimmable),
+			// the base alias-holder entry should be conditional (3-arg).
+			var peers = new List<JavaPeerInfo> {
+				MakeMcwPeer ("test/AllMcw", "Test.First", "A") with { DoNotGenerateAcw = true },
+				MakeMcwPeer ("test/AllMcw", "Test.Second", "A") with { DoNotGenerateAcw = true },
+			};
+
+			var model = BuildModel (peers);
+			var baseEntry = model.Entries.Single (e => e.JniName == "test/AllMcw");
+			Assert.False (baseEntry.IsUnconditional, "All-MCW alias group base entry should be conditional");
+			Assert.NotNull (baseEntry.TargetTypeReference);
+		}
+
+		[Fact]
+		public void Build_MixedAcwMcwAliasGroup_BaseEntryIsUnconditional ()
+		{
+			// When at least one peer in an alias group is an ACW (unconditional),
+			// the base alias-holder entry should be unconditional (2-arg).
+			var peers = new List<JavaPeerInfo> {
+				MakeMcwPeer ("test/Mixed", "Test.Mcw", "A") with { DoNotGenerateAcw = true },
+				MakeAcwPeer ("test/Mixed", "Test.Acw", "A"),
+			};
+
+			var model = BuildModel (peers);
+			var baseEntry = model.Entries.Single (e => e.JniName == "test/Mixed");
+			Assert.True (baseEntry.IsUnconditional, "Mixed alias group with ACW should have unconditional base entry");
+			Assert.Null (baseEntry.TargetTypeReference);
+		}
+
+		[Fact]
+		public void Build_EssentialTypeAliasGroup_BaseEntryIsUnconditional ()
+		{
+			// Essential runtime types (java/lang/Object etc.) should always be unconditional,
+			// even when all peers are MCW bindings.
+			var peers = new List<JavaPeerInfo> {
+				MakeMcwPeer ("java/lang/Object", "Java.Lang.Object", "Mono.Android"),
+				MakeMcwPeer ("java/lang/Object", "Java.Lang.Another", "Mono.Android"),
+			};
+
+			var model = BuildModel (peers);
+			var baseEntry = model.Entries.Single (e => e.JniName == "java/lang/Object");
+			Assert.True (baseEntry.IsUnconditional, "Essential type alias group should have unconditional base entry");
+			Assert.Null (baseEntry.TargetTypeReference);
+		}
 	}
 
 	public class ConditionalAttributes
@@ -172,14 +220,12 @@ public void Build_UserAcwType_IsUnconditional ()
 		public void Build_McwBinding_IsTrimmable ()
 		{
 			// MCW binding types (DoNotGenerateAcw=true) are trimmable unless essential.
-			// When ForceUnconditionalEntries is enabled (workaround for dotnet/runtime#127004),
-			// all entries become unconditional.
 			var peer = MakeMcwPeer ("android/app/Activity", "Android.App.Activity", "Mono.Android") with { DoNotGenerateAcw = true };
 			var model = BuildModel (new [] { peer });
 
 			Assert.Single (model.Entries);
-			Assert.True (model.Entries [0].IsUnconditional);
-			Assert.Null (model.Entries [0].TargetTypeReference);
+			Assert.False (model.Entries [0].IsUnconditional);
+			Assert.Equal ("Android.App.Activity, Mono.Android", model.Entries [0].TargetTypeReference);
 		}
 
 		[Fact]
@@ -248,8 +294,8 @@ public void Build_PeerWithActivation_CreatesNamedProxy (string jniName, string m
 		[Fact]
 		public void Build_SinglePeer_HasAssociation ()
 		{
-			// When ForceUnconditionalEntries is enabled, single peers emit associations
-			// so the runtime proxy type map is populated.
+			// Single peers with generated proxies emit associations so the runtime proxy
+			// type map is populated.
 			var peer = MakePeerWithActivation ("my/app/MainActivity", "MyApp.MainActivity", "App");
 			var model = BuildModel (new [] { peer }, "MyTypeMap");
 
@@ -338,8 +384,8 @@ public void Fixture_McwBinding_IsTrimmable (string javaName)
 			var peer = FindFixtureByJavaName (javaName);
 			Assert.True (peer.DoNotGenerateAcw);
 			var model = BuildModel (new [] { peer });
-			// ForceUnconditionalEntries workaround makes all entries unconditional
-			Assert.True (model.Entries [0].IsUnconditional);
+			Assert.False (model.Entries [0].IsUnconditional);
+			Assert.NotNull (model.Entries [0].TargetTypeReference);
 		}
 	}
 
@@ -776,7 +822,6 @@ public class PeBlobValidation
 		[Fact]
 		public void FullPipeline_Mixed2ArgAnd3Arg_BothSurviveRoundTrip ()
 		{
-			// With ForceUnconditionalEntries, both are emitted as 2-arg unconditional
 			var objectPeer = FindFixtureByJavaName ("java/lang/Object");
 			var activityPeer = FindFixtureByJavaName ("android/app/Activity");
 
@@ -793,7 +838,7 @@ public void FullPipeline_Mixed2ArgAnd3Arg_BothSurviveRoundTrip ()
 
 				var activityEntry = attrs.FirstOrDefault (a => a.jniName == "android/app/Activity");
 				Assert.NotNull (activityEntry.jniName);
-				Assert.Null (activityEntry.targetRef); // unconditional due to ForceUnconditionalEntries
+				Assert.Equal ("Android.App.Activity, TestFixtures", activityEntry.targetRef);
 			});
 		}
 
@@ -818,22 +863,20 @@ public void FullPipeline_UnconditionalType_Emits2ArgAttribute (string javaName,
 		}
 
 		[Fact]
-		public void FullPipeline_McwBinding_Emits2ArgAttribute_WithWorkaround ()
+		public void FullPipeline_McwBinding_Emits3ArgAttribute ()
 		{
-			// With ForceUnconditionalEntries workaround for dotnet/runtime#127004,
-			// MCW bindings are emitted as 2-arg unconditional.
 			var peer = FindFixtureByJavaName ("android/app/Activity");
-			var model = BuildModel (new [] { peer }, "Blob2ArgWorkaround");
+			var model = BuildModel (new [] { peer }, "Blob3ArgConditional");
 			Assert.Single (model.Entries);
-			Assert.True (model.Entries [0].IsUnconditional);
+			Assert.False (model.Entries [0].IsUnconditional);
 
-			EmitAndVerify (model, "Blob2ArgWorkaround", (pe, reader) => {
+			EmitAndVerify (model, "Blob3ArgConditional", (pe, reader) => {
 				var (jniName, proxyRef, targetRef) = ReadFirstTypeMapAttributeBlob (reader);
 
 				Assert.Equal ("android/app/Activity", jniName);
 				Assert.NotNull (proxyRef);
 				Assert.Contains ("Android_App_Activity_Proxy", proxyRef!);
-				Assert.Null (targetRef); // unconditional due to ForceUnconditionalEntries
+				Assert.Equal ("Android.App.Activity, TestFixtures", targetRef);
 			});
 		}
 	}