[TrimmableTypeMap] Add CoreCLRTrimmable Mono.Android.NET-Tests lane

build-tools/automation/yaml-templates/stage-package-tests.yaml

@@ -203,6 +203,16 @@ stages:
         artifactSource: bin/Test$(XA.Build.Configuration)/$(DotNetTargetFramework)-android/Mono.Android.NET_Tests-Signed.aab
         artifactFolder: $(DotNetTargetFramework)-CoreCLR
 
+    - template: /build-tools/automation/yaml-templates/apk-instrumentation.yaml
+      parameters:
+        configuration: $(XA.Build.Configuration)
+        testName: Mono.Android.NET_Tests-CoreCLRTrimmable
+        project: tests/Mono.Android-Tests/Mono.Android-Tests/Mono.Android.NET-Tests.csproj
+        testResultsFiles: TestResult-Mono.Android.NET_Tests-$(XA.Build.Configuration)CoreCLRTrimmable.xml
+        extraBuildArgs: -p:_AndroidTypeMapImplementation=trimmable -p:UseMonoRuntime=false
+        artifactSource: bin/Test$(XA.Build.Configuration)/$(DotNetTargetFramework)-android/Mono.Android.NET_Tests-Signed.aab
+        artifactFolder: $(DotNetTargetFramework)-CoreCLRTrimmable
+
     - template: /build-tools/automation/yaml-templates/apk-instrumentation.yaml
       parameters:
         configuration: $(XA.Build.Configuration)

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

@@ -16,6 +16,13 @@ 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",
@@ -122,8 +129,15 @@ static void EmitPeers (TypeMapAssemblyData model, string jniName,
 				model.ProxyTypes.Add (proxy);
 			}
 
-			model.Entries.Add (BuildEntry (peer, proxy, assemblyName, jniName));
-			if (proxy != null && peer.IsGenericDefinition) {
+			var entry = BuildEntry (peer, proxy, assemblyName, jniName);
+			model.Entries.Add (entry);
+
+			// Emit a TypeMapAssociation for every entry that has a proxy.
+			// The runtime's _proxyTypeMap (GetOrCreateProxyTypeMapping) is populated from
+			// TypeMapAssociationAttribute — NOT from TypeMapAttribute's 3rd arg.
+			// Without this, the proxy type map is empty and CreatePeer fails for
+			// interface types like IIterator where targetType-based lookup is needed.
+			if (proxy != null) {
 				model.Associations.Add (new TypeMapAssociationData {
 					SourceTypeReference = AssemblyQualify (peer.ManagedTypeName, peer.AssemblyName),
 					AliasProxyTypeReference = AssemblyQualify ($"{proxy.Namespace}.{proxy.TypeName}", assemblyName),
@@ -353,7 +367,9 @@ static TypeMapAttributeData BuildEntry (JavaPeerInfo peer, JavaPeerProxyData? pr
 			proxyRef = AssemblyQualify (peer.ManagedTypeName, peer.AssemblyName);
 		}
 
-		bool isUnconditional = IsUnconditionalEntry (peer);
+		// 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);
 		string? targetRef = null;
 		if (!isUnconditional) {
 			targetRef = AssemblyQualify (peer.ManagedTypeName, peer.AssemblyName);

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

@@ -313,7 +313,7 @@ public MethodDefinitionHandle EmitBody (string name, MethodAttributes attrs,
 			attrs, MethodImplAttributes.IL,
 			Metadata.GetOrAddString (name),
 			sigBlobHandle,
-			bodyOffset, default);
+			bodyOffset, MetadataTokens.ParameterHandle (Metadata.GetRowCount (TableIndex.Param) + 1));
 	}
 
 	/// <summary>
@@ -358,7 +358,7 @@ public MethodDefinitionHandle EmitBody (string name, MethodAttributes attrs,
 			attrs, MethodImplAttributes.IL,
 			Metadata.GetOrAddString (name),
 			sigBlobHandle,
-			bodyOffset, default);
+			bodyOffset, MetadataTokens.ParameterHandle (Metadata.GetRowCount (TableIndex.Param) + 1));
 	}
 
 	/// <summary>

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

@@ -75,6 +75,7 @@ sealed class TypeMapAssemblyEmitter
 	TypeReferenceHandle _iJavaPeerableRef;
 	TypeReferenceHandle _jniHandleOwnershipRef;
 	TypeReferenceHandle _jniObjectReferenceRef;
+	TypeReferenceHandle _jniObjectReferenceTypeRef;
 	TypeReferenceHandle _jniObjectReferenceOptionsRef;
 	TypeReferenceHandle _iAndroidCallableWrapperRef;
 	TypeReferenceHandle _jniEnvRef;
@@ -91,7 +92,7 @@ sealed class TypeMapAssemblyEmitter
 	MemberReferenceHandle _notSupportedExceptionCtorRef;
 	MemberReferenceHandle _jniObjectReferenceCtorRef;
 	MemberReferenceHandle _jniEnvDeleteRefRef;
-	MemberReferenceHandle _withinNewObjectScopeRef;
+	MemberReferenceHandle _shouldSkipActivationRef;
 	MemberReferenceHandle _ucoAttrCtorRef;
 	BlobHandle _ucoAttrBlobHandle;
 	MemberReferenceHandle _typeMapAttrCtorRef2Arg;
@@ -206,6 +207,8 @@ void EmitTypeReferences ()
 			metadata.GetOrAddString ("Android.Runtime"), metadata.GetOrAddString ("JNIEnv"));
 		_jniObjectReferenceRef = metadata.AddTypeReference (_javaInteropRef,
 			metadata.GetOrAddString ("Java.Interop"), metadata.GetOrAddString ("JniObjectReference"));
+		_jniObjectReferenceTypeRef = metadata.AddTypeReference (_javaInteropRef,
+			metadata.GetOrAddString ("Java.Interop"), metadata.GetOrAddString ("JniObjectReferenceType"));
 		_jniObjectReferenceOptionsRef = metadata.AddTypeReference (_javaInteropRef,
 			metadata.GetOrAddString ("Java.Interop"), metadata.GetOrAddString ("JniObjectReferenceOptions"));
 		_iAndroidCallableWrapperRef = metadata.AddTypeReference (_pe.MonoAndroidRef,
@@ -279,10 +282,16 @@ void EmitMemberReferences ()
 				rt => rt.Void (),
 				p => p.AddParameter ().Type ().String ()));
 
+		// JniObjectReference..ctor(IntPtr handle, JniObjectReferenceType type)
+		// Note: The C# constructor has a default parameter (type = Invalid), but in IL there is only
+		// the 2-parameter overload. We must emit both parameters explicitly.
 		_jniObjectReferenceCtorRef = _pe.AddMemberRef (_jniObjectReferenceRef, ".ctor",
-			sig => sig.MethodSignature (isInstanceMethod: true).Parameters (1,
+			sig => sig.MethodSignature (isInstanceMethod: true).Parameters (2,
 				rt => rt.Void (),
-				p => p.AddParameter ().Type ().IntPtr ()));
+				p => {
+					p.AddParameter ().Type ().IntPtr ();
+					p.AddParameter ().Type ().Type (_jniObjectReferenceTypeRef, true);
+				}));
 
 		// JNIEnv.DeleteRef(IntPtr, JniHandleOwnership) — static, internal
 		// Used by JI-style activation to clean up the original handle after constructing the peer.
@@ -295,11 +304,11 @@ void EmitMemberReferences ()
 					p.AddParameter ().Type ().Type (_jniHandleOwnershipRef, true);
 				}));
 
-		// JniEnvironment.get_WithinNewObjectScope() -> bool (static property)
-		_withinNewObjectScopeRef = _pe.AddMemberRef (_jniEnvironmentRef, "get_WithinNewObjectScope",
-			sig => sig.MethodSignature ().Parameters (0,
+		// JavaPeerProxy.ShouldSkipActivation(IntPtr) -> bool (static method)
+		_shouldSkipActivationRef = _pe.AddMemberRef (_javaPeerProxyNonGenericRef, "ShouldSkipActivation",
+			sig => sig.MethodSignature ().Parameters (1,
 				rt => rt.Type ().Boolean (),
-				p => { }));
+				p => { p.AddParameter ().Type ().IntPtr (); }));
 
 		// JniNativeMethod..ctor(byte*, byte*, IntPtr)
 		_jniNativeMethodCtorRef = _pe.AddMemberRef (_jniNativeMethodRef, ".ctor",
@@ -691,9 +700,10 @@ void EmitCreateInstanceViaJavaInteropNewobj (EntityHandle typeRef)
 		EmitCreateInstanceBodyWithLocals (
 			EncodeJniObjectReferenceAndObjectLocals,
 			encoder => {
-				// var jniRef = new JniObjectReference(handle);
+				// var jniRef = new JniObjectReference(handle, JniObjectReferenceType.Invalid);
 				encoder.LoadLocalAddress (0);
 				encoder.OpCode (ILOpCode.Ldarg_1); // handle
+				encoder.LoadConstantI4 (0); // JniObjectReferenceType.Invalid
 				encoder.Call (_jniObjectReferenceCtorRef);
 
 				// var result = new TargetType(ref jniRef, JniObjectReferenceOptions.Copy);
@@ -738,9 +748,10 @@ void EmitCreateInstanceInheritedJavaInteropCtor (EntityHandle targetTypeRef, Act
 				// dup obj (one copy for the call, one for the return)
 				encoder.OpCode (ILOpCode.Dup);
 
-				// var jniRef = new JniObjectReference(handle);
+				// var jniRef = new JniObjectReference(handle, JniObjectReferenceType.Invalid);
 				encoder.LoadLocalAddress (0);
 				encoder.OpCode (ILOpCode.Ldarg_1); // handle
+				encoder.LoadConstantI4 (0); // JniObjectReferenceType.Invalid
 				encoder.Call (_jniObjectReferenceCtorRef);
 
 				// obj.BaseCtor(ref jniRef, JniObjectReferenceOptions.Copy);
@@ -932,6 +943,7 @@ MethodDefinitionHandle EmitUcoConstructor (UcoConstructorData uco, JavaPeerProxy
 
 					enc.LoadLocalAddress (3); // jniRef
 					enc.LoadArgument (1);     // self
+					enc.LoadConstantI4 (0);   // JniObjectReferenceType.Invalid
 					enc.Call (_jniObjectReferenceCtorRef);
 
 					if (activationCtor.IsOnLeafType) {
@@ -990,7 +1002,7 @@ MethodDefinitionHandle EmitUcoConstructor (UcoConstructorData uco, JavaPeerProxy
 	/// <code>
 	/// if (!JniEnvironment.BeginMarshalMethod(jnienv, out envp, out runtime)) return;
 	/// try {
-	///     if (!JniEnvironment.WithinNewObjectScope) { [emitActivation] }
+	///     if (!JavaPeerProxy.ShouldSkipActivation(self)) { [emitActivation] }
 	/// } catch (Exception e) {
 	///     runtime?.OnUserUnhandledException(ref envp, e);
 	/// } finally {
@@ -1016,9 +1028,10 @@ void EmitUcoConstructorBodyWithMarshal (InstructionEncoder encoder, ControlFlowB
 		encoder.Call (_beginMarshalMethodRef);
 		encoder.Branch (ILOpCode.Brfalse, afterAll);
 
-		// TRY — check WithinNewObjectScope, then run activation code.
+		// TRY — check ShouldSkipActivation, then run activation code.
 		encoder.MarkLabel (tryStart);
-		encoder.Call (_withinNewObjectScopeRef);
+		encoder.LoadArgument (1);      // self (IntPtr)
+		encoder.Call (_shouldSkipActivationRef);
 		encoder.Branch (ILOpCode.Brtrue, skipLabel);
 
 		emitActivation (encoder);

src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/AssemblyIndex.cs

@@ -95,6 +95,8 @@ void Build ()
 			if (attrName == "RegisterAttribute") {
 				registerInfo = ParseRegisterAttribute (ca);
 				registerInfo = registerInfo with { JniName = registerInfo.JniName.Replace ('.', '/') };
+			} else if (attrName == "JniTypeSignatureAttribute") {
+				registerInfo = ParseJniTypeSignatureAttribute (ca);
 			} else if (attrName == "ExportAttribute") {
 				// [Export] is a method-level attribute; it is parsed at scan time by JavaPeerScanner
 			} else if (IsKnownComponentAttribute (attrName)) {
@@ -218,6 +220,28 @@ internal RegisterInfo ParseRegisterAttribute (CustomAttribute ca)
 		return ParseRegisterInfo (DecodeAttribute (ca));
 	}
 
+	internal RegisterInfo ParseJniTypeSignatureAttribute (CustomAttribute ca)
+	{
+		var value = DecodeAttribute (ca);
+
+		string jniName = "";
+		bool doNotGenerateAcw = false;
+
+		if (value.FixedArguments.Length > 0) {
+			jniName = (string?)value.FixedArguments [0].Value ?? "";
+		}
+
+		if (TryGetNamedArgument<bool> (value, "GenerateJavaPeer", out var generateJavaPeer)) {
+			doNotGenerateAcw = !generateJavaPeer;
+		}
+
+		return new RegisterInfo {
+			JniName = jniName.Replace ('.', '/'),
+			DoNotGenerateAcw = doNotGenerateAcw,
+			IsFromJniTypeSignature = true,
+		};
+	}
+
 	internal CustomAttributeValue<string> DecodeAttribute (CustomAttribute ca)
 	{
 		return ca.DecodeValue (customAttributeTypeProvider);
@@ -504,6 +528,7 @@ sealed record RegisterInfo
 	public string? Signature { get; init; }
 	public string? Connector { get; init; }
 	public bool DoNotGenerateAcw { get; init; }
+	public bool IsFromJniTypeSignature { get; init; }
 }
 
 /// <summary>

src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerInfo.cs

@@ -65,6 +65,13 @@ public sealed record JavaPeerInfo
 	/// </summary>
 	public bool DoNotGenerateAcw { get; init; }
 
+	/// <summary>
+	/// True when the type was discovered via <c>[JniTypeSignatureAttribute]</c>
+	/// rather than <c>[RegisterAttribute]</c>.  Used to resolve cross-assembly
+	/// alias ownership: <c>[Register]</c> types take precedence.
+	/// </summary>
+	public bool IsFromJniTypeSignature { get; init; }
+
 	/// <summary>
 	/// Types with component attributes ([Activity], [Service], etc.),
 	/// custom views from layout XML, or manifest-declared components

src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerScanner.cs

@@ -86,12 +86,15 @@ public List<JavaPeerInfo> Scan (IReadOnlyList<(string Name, PEReader Reader)> as
 			assemblyCache [index.AssemblyName] = index;
 		}
 
-		var resultsByManagedName = new Dictionary<string, JavaPeerInfo> (StringComparer.Ordinal);
+		// Key by (managedTypeName, assemblyName) to avoid collisions when two assemblies
+		// define a type with the same managed name (e.g. Java.Lang.Throwable in both
+		// Java.Interop and Mono.Android).
+		var resultsByQualifiedName = new Dictionary<(string ManagedName, string AssemblyName), JavaPeerInfo> ();
 		foreach (var index in assemblyCache.Values) {
-			ScanAssembly (index, resultsByManagedName);
+			ScanAssembly (index, resultsByQualifiedName);
 		}
-		ForceUnconditionalCrossReferences (resultsByManagedName, assemblyCache);
-		return new List<JavaPeerInfo> (resultsByManagedName.Values);
+		ForceUnconditionalCrossReferences (resultsByQualifiedName, assemblyCache);
+		return new List<JavaPeerInfo> (resultsByQualifiedName.Values);
 	}
 
 	/// <summary>
@@ -112,19 +115,19 @@ internal AssemblyManifestInfo ScanAssemblyManifestInfo ()
 	/// [Application(ManageSpaceActivity = typeof(X))] must be unconditional,
 	/// because the manifest will reference them even if nothing else does.
 	/// </summary>
-	static void ForceUnconditionalCrossReferences (Dictionary<string, JavaPeerInfo> resultsByManagedName, Dictionary<string, AssemblyIndex> assemblyCache)
+	static void ForceUnconditionalCrossReferences (Dictionary<(string ManagedName, string AssemblyName), JavaPeerInfo> results, Dictionary<string, AssemblyIndex> assemblyCache)
 	{
 		foreach (var index in assemblyCache.Values) {
 			foreach (var attrInfo in index.AttributesByType.Values) {
 				if (attrInfo is ApplicationAttributeInfo applicationAttributeInfo) {
-					ForceUnconditionalIfPresent (resultsByManagedName, applicationAttributeInfo.BackupAgent);
-					ForceUnconditionalIfPresent (resultsByManagedName, applicationAttributeInfo.ManageSpaceActivity);
+					ForceUnconditionalIfPresent (results, applicationAttributeInfo.BackupAgent);
+					ForceUnconditionalIfPresent (results, applicationAttributeInfo.ManageSpaceActivity);
 				}
 			}
 		}
 	}
 
-	static void ForceUnconditionalIfPresent (Dictionary<string, JavaPeerInfo> resultsByManagedName, string? managedTypeName)
+	static void ForceUnconditionalIfPresent (Dictionary<(string ManagedName, string AssemblyName), JavaPeerInfo> results, string? managedTypeName)
 	{
 		if (managedTypeName is null) {
 			return;
@@ -135,26 +138,27 @@ static void ForceUnconditionalIfPresent (Dictionary<string, JavaPeerInfo> result
 			return;
 		}
 
-		// Try exact match first (handles both plain and assembly-qualified names)
-		if (resultsByManagedName.TryGetValue (managedTypeName, out var peer)) {
-			resultsByManagedName [managedTypeName] = peer with { IsUnconditional = true };
-			return;
-		}
-
 		// TryGetTypeProperty may return assembly-qualified names like "Ns.Type, Assembly, ..."
 		// Strip to just the type name for lookup
 		var commaIndex = managedTypeName.IndexOf (',');
-		if (commaIndex <= 0) {
+		if (commaIndex > 0) {
+			managedTypeName = managedTypeName.Substring (0, commaIndex).Trim ();
+		}
+
+		if (managedTypeName.Length == 0) {
 			return;
 		}
 
-		var typeName = managedTypeName.Substring (0, commaIndex).Trim ();
-		if (typeName.Length > 0 && resultsByManagedName.TryGetValue (typeName, out peer)) {
-			resultsByManagedName [typeName] = peer with { IsUnconditional = true };
+		// Search by managed type name across all assemblies (BackupAgent/ManageSpaceActivity
+		// attribute values are not assembly-qualified).
+		foreach (var key in results.Keys) {
+			if (string.Equals (key.ManagedName, managedTypeName, StringComparison.Ordinal)) {
+				results [key] = results [key] with { IsUnconditional = true };
+			}
 		}
 	}
 
-	void ScanAssembly (AssemblyIndex index, Dictionary<string, JavaPeerInfo> results)
+	void ScanAssembly (AssemblyIndex index, Dictionary<(string ManagedName, string AssemblyName), JavaPeerInfo> results)
 	{
 		foreach (var typeHandle in index.Reader.TypeDefinitions) {
 			var typeDef = index.Reader.GetTypeDefinition (typeHandle);
@@ -237,6 +241,7 @@ void ScanAssembly (AssemblyIndex index, Dictionary<string, JavaPeerInfo> results
 				IsInterface = isInterface,
 				IsAbstract = isAbstract,
 				DoNotGenerateAcw = doNotGenerateAcw,
+				IsFromJniTypeSignature = registerInfo?.IsFromJniTypeSignature ?? false,
 				IsUnconditional = isUnconditional,
 				CannotRegisterInStaticConstructor = cannotRegisterInStaticConstructor,
 				MarshalMethods = marshalMethods,
@@ -248,7 +253,7 @@ void ScanAssembly (AssemblyIndex index, Dictionary<string, JavaPeerInfo> results
 				ComponentAttribute = ToComponentInfo (attrInfo),
 			};
 
-			results [fullName] = peer;
+			results [(fullName, index.AssemblyName)] = peer;
 		}
 	}
 
@@ -901,7 +906,7 @@ static string GetJavaAccess (MethodAttributes access)
 		};
 	}
 
-	string? ResolveBaseJavaName (TypeDefinition typeDef, AssemblyIndex index, Dictionary<string, JavaPeerInfo> results)
+	string? ResolveBaseJavaName (TypeDefinition typeDef, AssemblyIndex index, Dictionary<(string ManagedName, string AssemblyName), JavaPeerInfo> results)
 	{
 		if (!TryResolveBaseType (typeDef, index, out var baseTypeDef, out _, out var baseIndex, out var baseTypeName, out _)) {
 			return null;
@@ -914,7 +919,7 @@ static string GetJavaAccess (MethodAttributes access)
 		}
 
 		// Fall back to already-scanned results (component-attributed or CRC64-computed peers)
-		if (results.TryGetValue (baseTypeName, out var basePeer)) {
+		if (results.TryGetValue ((baseTypeName, baseIndex.AssemblyName), out var basePeer)) {
 			return basePeer.JavaName;
 		}