[TrimmableTypeMap] fix JavaPeerableProxy activation gref leak

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

@@ -27,7 +27,7 @@ namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 ///     // Creates the managed peer when Java calls into .NET
 ///     public override IJavaPeerable CreateInstance(IntPtr handle, JniHandleOwnership ownership)
 ///         => new Activity(handle, ownership);                        // leaf ctor
-///         // or: (Activity)RuntimeHelpers.GetUninitializedObject(typeof(Activity));
+///         // or: (Activity)CreateActivatedPeer(typeof(Activity), handle);
 ///         //     obj.BaseCtor(handle, ownership);                     // inherited ctor
 ///         // or: new IOnClickListenerInvoker(handle, ownership);      // interface invoker
 ///         // or: null;                                                // no activation
@@ -43,7 +43,7 @@ namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 ///     [UnmanagedCallersOnly]
 ///     public static void nctor_0_uco(IntPtr jnienv, IntPtr self)
 ///         => new Activity(self, JniHandleOwnership.DoNotTransfer);
-///         // or: var obj = (Activity)RuntimeHelpers.GetUninitializedObject(typeof(Activity));
+///         // or: var obj = (Activity)CreateActivatedPeer(typeof(Activity), self);
 ///         //     obj.BaseCtor(self, JniHandleOwnership.DoNotTransfer);
 ///
 ///     // Registers JNI native methods (ACWs only):
@@ -68,6 +68,7 @@ sealed class TypeMapAssemblyEmitter
 
 	AssemblyReferenceHandle _javaInteropRef;
 
+	TypeReferenceHandle _javaPeerProxyBaseRef;
 	TypeReferenceHandle _javaPeerProxyRef;
 	TypeReferenceHandle _iJavaPeerableRef;
 	TypeReferenceHandle _jniHandleOwnershipRef;
@@ -79,10 +80,9 @@ sealed class TypeMapAssemblyEmitter
 	TypeReferenceHandle _runtimeTypeHandleRef;
 	TypeReferenceHandle _jniTypeRef;
 	TypeReferenceHandle _notSupportedExceptionRef;
-	TypeReferenceHandle _runtimeHelpersRef;
 
 	MemberReferenceHandle _getTypeFromHandleRef;
-	MemberReferenceHandle _getUninitializedObjectRef;
+	MemberReferenceHandle _createActivatedPeerRef;
 	MemberReferenceHandle _notSupportedExceptionCtorRef;
 	MemberReferenceHandle _jniObjectReferenceCtorRef;
 	MemberReferenceHandle _jniEnvDeleteRefRef;
@@ -163,6 +163,8 @@ void EmitCore (TypeMapAssemblyData model)
 	void EmitTypeReferences ()
 	{
 		var metadata = _pe.Metadata;
+		_javaPeerProxyBaseRef = metadata.AddTypeReference (_pe.MonoAndroidRef,
+			metadata.GetOrAddString ("Java.Interop"), metadata.GetOrAddString ("JavaPeerProxy"));
 		_javaPeerProxyRef = metadata.AddTypeReference (_pe.MonoAndroidRef,
 			metadata.GetOrAddString ("Java.Interop"), metadata.GetOrAddString ("JavaPeerProxy`1"));
 		_iJavaPeerableRef = metadata.AddTypeReference (_javaInteropRef,
@@ -185,8 +187,6 @@ void EmitTypeReferences ()
 			metadata.GetOrAddString ("Java.Interop"), metadata.GetOrAddString ("JniType"));
 		_notSupportedExceptionRef = metadata.AddTypeReference (_pe.SystemRuntimeRef,
 			metadata.GetOrAddString ("System"), metadata.GetOrAddString ("NotSupportedException"));
-		_runtimeHelpersRef = metadata.AddTypeReference (_pe.SystemRuntimeRef,
-			metadata.GetOrAddString ("System.Runtime.CompilerServices"), metadata.GetOrAddString ("RuntimeHelpers"));
 
 		_jniNativeMethodRef = metadata.AddTypeReference (_javaInteropRef,
 			metadata.GetOrAddString ("Java.Interop"), metadata.GetOrAddString ("JniNativeMethod"));
@@ -208,10 +208,13 @@ void EmitMemberReferences ()
 				rt => rt.Type ().Type (_systemTypeRef, false),
 				p => p.AddParameter ().Type ().Type (_runtimeTypeHandleRef, true)));
 
-		_getUninitializedObjectRef = _pe.AddMemberRef (_runtimeHelpersRef, "GetUninitializedObject",
-			sig => sig.MethodSignature ().Parameters (1,
-				rt => rt.Type ().Object (),
-				p => p.AddParameter ().Type ().Type (_systemTypeRef, false)));
+		_createActivatedPeerRef = _pe.AddMemberRef (_javaPeerProxyBaseRef, "CreateActivatedPeer",
+			sig => sig.MethodSignature ().Parameters (2,
+				rt => rt.Type ().Type (_iJavaPeerableRef, false),
+				p => {
+					p.AddParameter ().Type ().Type (_systemTypeRef, false);
+					p.AddParameter ().Type ().IntPtr ();
+				}));
 
 		_notSupportedExceptionCtorRef = _pe.AddMemberRef (_notSupportedExceptionRef, ".ctor",
 			sig => sig.MethodSignature (isInstanceMethod: true).Parameters (1,
@@ -493,7 +496,8 @@ void EmitCreateInstanceInheritedCtor (EntityHandle targetTypeRef, ActivationCtor
 			encoder.OpCode (ILOpCode.Ldtoken);
 			encoder.Token (targetTypeRef);
 			encoder.Call (_getTypeFromHandleRef);
-			encoder.Call (_getUninitializedObjectRef);
+			encoder.OpCode (ILOpCode.Ldarg_1);
+			encoder.Call (_createActivatedPeerRef);
 			encoder.OpCode (ILOpCode.Castclass);
 			encoder.Token (targetTypeRef);
 
@@ -543,7 +547,7 @@ void EmitCreateInstanceViaJavaInteropNewobj (EntityHandle typeRef)
 
 	/// <summary>
 	/// Emits CreateInstance for JavaInterop-style activation (inherited ctor):
-	///   var obj = (TargetType)RuntimeHelpers.GetUninitializedObject(typeof(TargetType));
+	///   var obj = (TargetType)CreateActivatedPeer(typeof(TargetType), handle);
 	///   var jniRef = new JniObjectReference(handle);
 	///   obj.BaseCtor(ref jniRef, JniObjectReferenceOptions.Copy);
 	///   JNIEnv.DeleteRef(handle, ownership);
@@ -555,11 +559,12 @@ void EmitCreateInstanceInheritedJavaInteropCtor (EntityHandle targetTypeRef, Act
 		EmitCreateInstanceBodyWithLocals (
 			EncodeJniObjectReferenceLocal,
 			encoder => {
-				// var obj = (TargetType)RuntimeHelpers.GetUninitializedObject(typeof(TargetType));
+				// var obj = (TargetType)CreateActivatedPeer(typeof(TargetType), handle);
 				encoder.OpCode (ILOpCode.Ldtoken);
 				encoder.Token (targetTypeRef);
 				encoder.Call (_getTypeFromHandleRef);
-				encoder.Call (_getUninitializedObjectRef);
+				encoder.OpCode (ILOpCode.Ldarg_1); // handle
+				encoder.Call (_createActivatedPeerRef);
 				encoder.OpCode (ILOpCode.Castclass);
 				encoder.Token (targetTypeRef);
 
@@ -743,7 +748,8 @@ MethodDefinitionHandle EmitUcoConstructor (UcoConstructorData uco, JavaPeerProxy
 						encoder.OpCode (ILOpCode.Ldtoken);
 						encoder.Token (targetTypeRef);
 						encoder.Call (_getTypeFromHandleRef);
-						encoder.Call (_getUninitializedObjectRef);
+						encoder.LoadArgument (1); // self
+						encoder.Call (_createActivatedPeerRef);
 						encoder.OpCode (ILOpCode.Castclass);
 						encoder.Token (targetTypeRef);
 					}
@@ -792,7 +798,8 @@ MethodDefinitionHandle EmitUcoConstructor (UcoConstructorData uco, JavaPeerProxy
 						encoder.OpCode (ILOpCode.Ldtoken);
 						encoder.Token (targetTypeRef);
 						encoder.Call (_getTypeFromHandleRef);
-						encoder.Call (_getUninitializedObjectRef);
+						encoder.LoadArgument (1); // self
+						encoder.Call (_createActivatedPeerRef);
 						encoder.OpCode (ILOpCode.Castclass);
 						encoder.Token (targetTypeRef);
 

src/Mono.Android/Java.Interop/JavaPeerProxy.cs

@@ -18,10 +18,12 @@ namespace Java.Interop
 	[AttributeUsage (AttributeTargets.Class | AttributeTargets.Interface, Inherited = false, AllowMultiple = false)]
 	public abstract class JavaPeerProxy : Attribute
 	{
+		const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
+
 		protected JavaPeerProxy (
 			string jniName,
 			Type targetType,
-			[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+			[DynamicallyAccessedMembers (Constructors)]
 			Type? invokerType)
 		{
 			JniName = jniName ?? throw new ArgumentNullException (nameof (jniName));
@@ -52,7 +54,7 @@ protected JavaPeerProxy (
 		/// Gets the invoker type for interfaces and abstract classes.
 		/// Returns null for concrete types that can be directly instantiated.
 		/// </summary>
-		[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+		[DynamicallyAccessedMembers (Constructors)]
 		public Type? InvokerType { get; }
 
 		/// <summary>
@@ -61,6 +63,22 @@ protected JavaPeerProxy (
 		/// </summary>
 		/// <returns>A factory for creating containers of the target type, or null if not supported.</returns>
 		public virtual JavaPeerContainerFactory? GetContainerFactory () => null;
+		/// <summary>
+		/// Creates the managed peer for inherited Java activation paths and binds it
+		/// to the provided JNI handle before the activation constructor runs.
+		/// </summary>
+		protected static IJavaPeerable CreateActivatedPeer (
+			[DynamicallyAccessedMembers (Constructors)] Type type,
+			IntPtr handle)
+		{
+			var peer = (IJavaPeerable) System.Runtime.CompilerServices.RuntimeHelpers.GetUninitializedObject (type);
+
+			peer.SetJniManagedPeerState (peer.JniManagedPeerState | JniManagedPeerStates.Replaceable | JniManagedPeerStates.Activatable);
+
+			var reference = new JniObjectReference (handle);
+			JniEnvironment.Runtime.ValueManager.ConstructPeer (peer, ref reference, JniObjectReferenceOptions.Copy);
+			return peer;
+		}
 	}
 
 	/// <summary>

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

@@ -176,7 +176,7 @@ public void Generate_EmptyPeerList_ProducesValidAssembly ()
 	}
 
 	[Fact]
-	public void Generate_SimpleActivity_UsesGetUninitializedObject ()
+	public void Generate_SimpleActivity_UsesSharedActivationHelper ()
 	{
 		var peers = ScanFixtures ();
 		var simpleActivity = peers.First (p => p.JavaName == "my/app/SimpleActivity");
@@ -186,12 +186,11 @@ public void Generate_SimpleActivity_UsesGetUninitializedObject ()
 		using var stream = GenerateAssembly (new [] { simpleActivity }, "InheritedCtorTest");
 		using var pe = new PEReader (stream);
 		var reader = pe.GetMetadataReader ();
-		var typeNames = GetTypeRefNames (reader);
-		Assert.Contains ("RuntimeHelpers", typeNames);
 
 		var memberNames = GetMemberRefNames (reader);
 		Assert.DoesNotContain ("CreateManagedPeer", memberNames);
-		Assert.Contains ("GetUninitializedObject", memberNames);
+		Assert.Contains ("CreateActivatedPeer", memberNames);
+		Assert.DoesNotContain ("GetUninitializedObject", memberNames);
 	}
 
 	[Fact]
@@ -230,7 +229,8 @@ public void Generate_InheritedCtor_UcoUsesGuardAndInlinedActivation ()
 		var memberNames = GetMemberRefNames (reader);
 
 		Assert.Contains ("get_WithinNewObjectScope", memberNames);
-		Assert.Contains ("GetUninitializedObject", memberNames);
+		Assert.Contains ("CreateActivatedPeer", memberNames);
+		Assert.DoesNotContain ("GetUninitializedObject", memberNames);
 		Assert.DoesNotContain ("ActivateInstance", memberNames);
 		Assert.DoesNotContain ("ActivatePeerFromJavaConstructor", memberNames);
 	}