From efbce2eb2ee06d35658e3c81d295c7db888c25eb Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 11:23:59 +0200
Subject: [PATCH 1/8] Remove ManagedPeer from trimmable type map apps

Disable Java.Interop ManagedPeer native registration for trimmable type map builds and remove the Java ManagedPeer class from the trimmable runtime jar. The trimmable path registers native methods through generated JCW static initializers, so ManagedPeer is dead weight there.

Add coverage to ensure trimmable runtime artifacts, generated Java, and built APK dex files do not reference ManagedPeer.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop                         |  2 +-
 ...soft.Android.Sdk.TypeMap.Trimmable.targets |  4 ++
 .../TrimmableTypeMapBuildTests.cs             | 66 ++++++++++++++++++-
 src/java-runtime/java-runtime.targets         |  2 +-
 4 files changed, 70 insertions(+), 4 deletions(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index d546a083f31..51bade624ce 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit d546a083f3139243243959fbf1d9b7d35f6c2cbf
+Subproject commit 51bade624ceeabf9603fc77a6f4f9d9682860fe8
diff --git a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
index b040052577f..a02d1dbec37 100644
--- a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
+++ b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
@@ -33,6 +33,10 @@
   <ItemGroup>
     <RuntimeHostConfigurationOption Include="Microsoft.Android.Runtime.RuntimeFeature.TrimmableTypeMap"
         Value="true" Trim="true" />
+    <!-- The feature switch is defined in Java.Interop, but trimmable app builds
+         own the runtimeconfig value that lets ILLink substitute it. -->
+    <RuntimeHostConfigurationOption Include="Java.Interop.RuntimeFeature.ManagedPeerNativeRegistration"
+        Value="false" Trim="true" />
     <RuntimeHostConfigurationOption Include="System.Runtime.InteropServices.TypeMappingEntryAssembly"
         Value="$(_TypeMapAssemblyName)" />
     <!-- [Export] metadata is still needed at compile time, but the legacy runtime helper
diff --git a/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs b/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs
index 93195ece435..859c20fa17d 100644
--- a/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs
@@ -2,10 +2,12 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Text;
 using System.Text.RegularExpressions;
 using NUnit.Framework;
 using Xamarin.Android.Tasks;
 using Xamarin.ProjectTools;
+using Xamarin.Tools.Zip;
 
 namespace Xamarin.Android.Build.Tests {
 	[TestFixture]
@@ -229,6 +231,15 @@ public void TrimmableTypeMap_RuntimeArtifacts_ArePackagedInSdk ()
 				FileAssert.Exists (Path.Combine (toolsDir, file), $"{file} should exist in the SDK pack.");
 			}
 
+			var trimmableJar = Path.Combine (toolsDir, "java_runtime_trimmable.jar");
+			using (var zip = ZipArchive.Open (trimmableJar, FileMode.Open)) {
+				zip.AssertDoesNotContainEntry (trimmableJar, "net/dot/jni/ManagedPeer.class");
+			}
+
+			var trimmableDex = Path.Combine (toolsDir, "java_runtime_trimmable.dex");
+			Assert.IsFalse (
+				FileContainsAscii (trimmableDex, "Lnet/dot/jni/ManagedPeer;"),
+				"java_runtime_trimmable.dex should not contain the Java ManagedPeer type descriptor.");
 		}
 
 		// T1: end-to-end build coverage for [Export] and [ExportField] under trimmable.
@@ -284,10 +295,11 @@ class ExportShapes : Java.Lang.Object {
 			string? exportShapesText = null;
 			foreach (var f in allJavaFiles) {
 				var text = File.ReadAllText (f);
-				if (text.Contains ("EchoString") && text.Contains ("InitialFoo")) {
+				StringAssert.DoesNotContain ("net.dot.jni.ManagedPeer", text,
+					$"Trimmable generated Java source should not reference net.dot.jni.ManagedPeer: {f}");
+				if (exportShapesJava == null && text.Contains ("EchoString") && text.Contains ("InitialFoo")) {
 					exportShapesJava = f;
 					exportShapesText = text;
-					break;
 				}
 			}
 			Assert.IsNotNull (exportShapesJava,
@@ -318,6 +330,9 @@ class ExportShapes : Java.Lang.Object {
 			var typemapDir = builder.Output.GetIntermediaryPath ("typemap");
 			var typemapDlls = Directory.GetFiles (typemapDir, "*.TypeMap.dll");
 			Assert.IsNotEmpty (typemapDlls, "Trimmable typemap should produce at least one *.TypeMap.dll.");
+
+			var apk = Path.Combine (Root, builder.ProjectDirectory, proj.OutputPath, $"{proj.PackageName}-Signed.apk");
+			AssertApkDexDoesNotContain (apk, "Lnet/dot/jni/ManagedPeer;");
 		}
 
 		// T6: trim-warning baseline for [Export] under trimmable.
@@ -425,5 +440,52 @@ public ConcreteProvider (Android.Content.Context context) : base (context) { }
 			using var builder = CreateApkBuilder ();
 			Assert.IsTrue (builder.Build (proj), "Build should have succeeded — abstract types with protected ctors should not cause XAGTT7009.");
 		}
+
+		static void AssertApkDexDoesNotContain (string apk, string value)
+		{
+			FileAssert.Exists (apk);
+			using var zip = ZipArchive.Open (apk, FileMode.Open);
+			var dexEntries = zip
+				.Where (entry => entry.FullName.StartsWith ("classes", StringComparison.Ordinal) &&
+					entry.FullName.EndsWith (".dex", StringComparison.Ordinal))
+				.ToArray ();
+			Assert.IsNotEmpty (dexEntries, $"{apk} should contain at least one dex file.");
+
+			foreach (var entry in dexEntries) {
+				Assert.IsFalse (
+					EntryContainsAscii (entry, value),
+					$"{entry.FullName} should not contain {value}.");
+			}
+		}
+
+		static bool EntryContainsAscii (ZipEntry entry, string value)
+		{
+			using var stream = new MemoryStream ();
+			entry.Extract (stream);
+			return ContainsAscii (stream.ToArray (), value);
+		}
+
+		static bool FileContainsAscii (string file, string value)
+		{
+			return ContainsAscii (File.ReadAllBytes (file), value);
+		}
+
+		static bool ContainsAscii (byte [] data, string value)
+		{
+			var pattern = Encoding.ASCII.GetBytes (value);
+			for (int i = 0; i <= data.Length - pattern.Length; i++) {
+				bool found = true;
+				for (int j = 0; j < pattern.Length; j++) {
+					if (data [i + j] != pattern [j]) {
+						found = false;
+						break;
+					}
+				}
+				if (found) {
+					return true;
+				}
+			}
+			return false;
+		}
 	}
 }
diff --git a/src/java-runtime/java-runtime.targets b/src/java-runtime/java-runtime.targets
index 7f57a85582c..8503e55a9ad 100644
--- a/src/java-runtime/java-runtime.targets
+++ b/src/java-runtime/java-runtime.targets
@@ -14,7 +14,7 @@
     <OutputDex>$(OutputPath)java_runtime_trimmable.dex</OutputDex>
     <IntermediateRuntimeOutputPath>$(IntermediateOutputPath)release-trimmable</IntermediateRuntimeOutputPath>
     <IntermediateRuntimeClassesTxt>$(IntermediateOutputPath)release-trimmable.txt</IntermediateRuntimeClassesTxt>
-    <RemoveItems>..\..\src-ThirdParty\bazel\java\mono\android\debug\MultiDexLoader.java;java\mono\android\debug-net6\BuildConfig.java;java\mono\android\debug\BuildConfig.java;java\mono\android\release\BuildConfig.java;java\mono\android\MonoPackageManager.java;$(JavaInteropSourceDirectory)\src\Java.Interop\java\net\dot\jni\internal\JavaProxyObject.java;$(JavaInteropSourceDirectory)\src\Java.Interop\java\net\dot\jni\internal\JavaProxyThrowable.java</RemoveItems>
+    <RemoveItems>..\..\src-ThirdParty\bazel\java\mono\android\debug\MultiDexLoader.java;java\mono\android\debug-net6\BuildConfig.java;java\mono\android\debug\BuildConfig.java;java\mono\android\release\BuildConfig.java;java\mono\android\MonoPackageManager.java;$(JavaInteropSourceDirectory)\src\Java.Interop\java\net\dot\jni\ManagedPeer.java;$(JavaInteropSourceDirectory)\src\Java.Interop\java\net\dot\jni\internal\JavaProxyObject.java;$(JavaInteropSourceDirectory)\src\Java.Interop\java\net\dot\jni\internal\JavaProxyThrowable.java</RemoveItems>
     <AddItems>java-trimmable\net\dot\jni\internal\JavaProxyObject.java;java-trimmable\net\dot\jni\internal\JavaProxyThrowable.java</AddItems>
   </_RuntimeOutput>
   <_RuntimeOutput Include="$(OutputPath)java_runtime_fastdev.jar">

From dbae16f869af82eb7fc17cc9d6d85f8a1811afdd Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 12:08:51 +0200
Subject: [PATCH 2/8] Disable ManagedPeer registration from Android runtime

Remove the Java.Interop runtimeconfig switch from the trimmable typemap targets. Android now disables the legacy ManagedPeer native registration path through JniRuntime.CreationOptions when the existing trimmable typemap runtime feature is enabled.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop                                         | 2 +-
 src/Mono.Android/Android.Runtime/AndroidRuntime.cs            | 1 +
 .../targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets   | 4 ----
 3 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index 51bade624ce..7fc93f2b4da 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit 51bade624ceeabf9603fc77a6f4f9d9682860fe8
+Subproject commit 7fc93f2b4da904f101004dcdfc995016b100de2e
diff --git a/src/Mono.Android/Android.Runtime/AndroidRuntime.cs b/src/Mono.Android/Android.Runtime/AndroidRuntime.cs
index 918b8377b54..3228d9afbae 100644
--- a/src/Mono.Android/Android.Runtime/AndroidRuntime.cs
+++ b/src/Mono.Android/Android.Runtime/AndroidRuntime.cs
@@ -110,6 +110,7 @@ public AndroidRuntimeOptions (IntPtr jnienv,
 			TypeManager             = typeManager;
 			ValueManager            = valueManager;
 			JniAddNativeMethodRegistrationAttributePresent = jniAddNativeMethodRegistrationAttributePresent;
+			ManagedPeerNativeRegistration = !RuntimeFeature.TrimmableTypeMap;
 		}
 	}
 
diff --git a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
index a02d1dbec37..b040052577f 100644
--- a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
+++ b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
@@ -33,10 +33,6 @@
   <ItemGroup>
     <RuntimeHostConfigurationOption Include="Microsoft.Android.Runtime.RuntimeFeature.TrimmableTypeMap"
         Value="true" Trim="true" />
-    <!-- The feature switch is defined in Java.Interop, but trimmable app builds
-         own the runtimeconfig value that lets ILLink substitute it. -->
-    <RuntimeHostConfigurationOption Include="Java.Interop.RuntimeFeature.ManagedPeerNativeRegistration"
-        Value="false" Trim="true" />
     <RuntimeHostConfigurationOption Include="System.Runtime.InteropServices.TypeMappingEntryAssembly"
         Value="$(_TypeMapAssemblyName)" />
     <!-- [Export] metadata is still needed at compile time, but the legacy runtime helper

From f1f0c42fdef6311bf339993503245fed3bbc524a Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 12:18:39 +0200
Subject: [PATCH 3/8] Address trimmable ManagedPeer review feedback

Use Span.IndexOf for the test dex byte search and update the Java.Interop submodule with the ManagedPeer runtime-option review fixes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop                              |  2 +-
 .../TrimmableTypeMapBuildTests.cs                  | 14 +-------------
 2 files changed, 2 insertions(+), 14 deletions(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index 7fc93f2b4da..0b3a35a0344 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit 7fc93f2b4da904f101004dcdfc995016b100de2e
+Subproject commit 0b3a35a0344cf4c3ae0f53226271f3400783c442
diff --git a/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs b/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs
index 859c20fa17d..30743773cf5 100644
--- a/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs
@@ -473,19 +473,7 @@ static bool FileContainsAscii (string file, string value)
 		static bool ContainsAscii (byte [] data, string value)
 		{
 			var pattern = Encoding.ASCII.GetBytes (value);
-			for (int i = 0; i <= data.Length - pattern.Length; i++) {
-				bool found = true;
-				for (int j = 0; j < pattern.Length; j++) {
-					if (data [i + j] != pattern [j]) {
-						found = false;
-						break;
-					}
-				}
-				if (found) {
-					return true;
-				}
-			}
-			return false;
+			return data.AsSpan ().IndexOf (pattern) >= 0;
 		}
 	}
 }

From 6a24e8839d62ad9d41c6bba9d1ea66209a32f672 Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 12:27:26 +0200
Subject: [PATCH 4/8] Update Java.Interop ManagedPeer review coverage

Bring in the Java.Interop regression test that documents ManagedPeer is intentionally absent from the built-in simple-reference map.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index 0b3a35a0344..7d04ce48be3 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit 0b3a35a0344cf4c3ae0f53226271f3400783c442
+Subproject commit 7d04ce48be38f36fe403911a27d997a502cec6f1

From 33c3a13a429e563aae60752cbd1c1c221465c7d0 Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 12:39:11 +0200
Subject: [PATCH 5/8] Disable ManagedPeer through Java.Interop runtime switch

Set Java.Interop.RuntimeFeature.ManagedPeerNativeRegistration=false for the trimmable typemap path and update the Java.Interop submodule to keep legacy ManagedPeer behavior enabled by default elsewhere.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop                                           | 2 +-
 src/Mono.Android/Android.Runtime/AndroidRuntime.cs              | 1 -
 .../targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets     | 2 ++
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index 7d04ce48be3..7c20f13529b 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit 7d04ce48be38f36fe403911a27d997a502cec6f1
+Subproject commit 7c20f13529bf5a69d4a9b14be64432c324fb847c
diff --git a/src/Mono.Android/Android.Runtime/AndroidRuntime.cs b/src/Mono.Android/Android.Runtime/AndroidRuntime.cs
index 3228d9afbae..918b8377b54 100644
--- a/src/Mono.Android/Android.Runtime/AndroidRuntime.cs
+++ b/src/Mono.Android/Android.Runtime/AndroidRuntime.cs
@@ -110,7 +110,6 @@ public AndroidRuntimeOptions (IntPtr jnienv,
 			TypeManager             = typeManager;
 			ValueManager            = valueManager;
 			JniAddNativeMethodRegistrationAttributePresent = jniAddNativeMethodRegistrationAttributePresent;
-			ManagedPeerNativeRegistration = !RuntimeFeature.TrimmableTypeMap;
 		}
 	}
 
diff --git a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
index b040052577f..ed881993fea 100644
--- a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
+++ b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
@@ -33,6 +33,8 @@
   <ItemGroup>
     <RuntimeHostConfigurationOption Include="Microsoft.Android.Runtime.RuntimeFeature.TrimmableTypeMap"
         Value="true" Trim="true" />
+    <RuntimeHostConfigurationOption Include="Java.Interop.RuntimeFeature.ManagedPeerNativeRegistration"
+        Value="false" Trim="true" />
     <RuntimeHostConfigurationOption Include="System.Runtime.InteropServices.TypeMappingEntryAssembly"
         Value="$(_TypeMapAssemblyName)" />
     <!-- [Export] metadata is still needed at compile time, but the legacy runtime helper

From f102337d95ea4405b7d1f64f7d05ce2e737af27d Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 12:43:21 +0200
Subject: [PATCH 6/8] Update Java.Interop ManagedPeer switch tests

Bring in the Java.Interop coverage that verifies Java.Interop.RuntimeFeature.ManagedPeerNativeRegistration=false skips ManagedPeer.Init().

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index 7c20f13529b..5e109914b68 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit 7c20f13529bf5a69d4a9b14be64432c324fb847c
+Subproject commit 5e109914b6892f7a525401197b4e30c5b85892b9

From e4039a458999f86ac8b45534cbb7da9f94a926c8 Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 12:49:30 +0200
Subject: [PATCH 7/8] Update Java.Interop ManagedPeer test fix

Update the Java.Interop dependency to remove test-only ManagedPeer production instrumentation while keeping the ManagedPeer runtime switch coverage.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index 5e109914b68..480feefd309 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit 5e109914b6892f7a525401197b4e30c5b85892b9
+Subproject commit 480feefd309bedcb30af8f8860fc2536a50053b2

From d1ea7d9a1c2ffc7ea87cc26e728b4b13723e2a87 Mon Sep 17 00:00:00 2001
From: Simon Rozsival <simon@rozsival.com>
Date: Mon, 25 May 2026 13:05:24 +0200
Subject: [PATCH 8/8] Update Java.Interop ManagedPeer switch fix

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 external/Java.Interop | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/external/Java.Interop b/external/Java.Interop
index 480feefd309..5788d5fb10d 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit 480feefd309bedcb30af8f8860fc2536a50053b2
+Subproject commit 5788d5fb10dfd38309d5665e1d5c352e12f85932