[TrimmableTypeMap] Generator correctness fixes

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

@@ -44,8 +44,7 @@ static class ComponentElementBuilder
 			element.Add (CreateIntentFilterElement (intentFilter));
 		}
 
-		// Add <layout> element from a [Layout] attribute, if present
-		if (component.LayoutProperties is not null) {
+		if (component.Kind == ComponentKind.Activity && component.LayoutProperties is not null) {
 			var layout = CreateLayoutElement (component.LayoutProperties);
 			if (layout is not null) {
 				element.Add (layout);

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

@@ -516,7 +516,7 @@ internal static void ApplyPlaceholders (XDocument doc, string? placeholders, str
 		if (!placeholders.IsNullOrEmpty ()) {
 			foreach (var entry in placeholders.Split (PlaceholderSeparators, StringSplitOptions.RemoveEmptyEntries)) {
 				var eqIndex = entry.IndexOf ('=');
-				if (eqIndex > 0) {
+				if (eqIndex >= 0) {
 					var key = entry.Substring (0, eqIndex).Trim ();
 					var value = entry.Substring (eqIndex + 1).Trim ();
 					replacements ["${" + key + "}"] = value;

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

@@ -102,9 +102,8 @@ public static TypeMapAssemblyData Build (IReadOnlyList<JavaPeerInfo> peers, stri
 			string jniName = kvp.Key;
 			var peersForName = kvp.Value;
 
-			// Sort aliases by managed type name for deterministic proxy naming
 			if (peersForName.Count > 1) {
-				peersForName.Sort ((a, b) => StringComparer.Ordinal.Compare (a.ManagedTypeName, b.ManagedTypeName));
+				peersForName.Sort (CompareAliasesForRuntimeResolution);
 			}
 
 			EmitPeers (model, jniName, peersForName, assemblyName, usedProxyNames);
@@ -141,6 +140,19 @@ public static TypeMapAssemblyData Build (IReadOnlyList<JavaPeerInfo> peers, stri
 		return model;
 	}
 
+	static int CompareAliasesForRuntimeResolution (JavaPeerInfo a, JavaPeerInfo b)
+	{
+		// Keep alias [0] aligned with the native java→managed map, which processes Mono.Android first.
+		bool aMonoAndroid = string.Equals (a.AssemblyName, "Mono.Android", StringComparison.Ordinal);
+		bool bMonoAndroid = string.Equals (b.AssemblyName, "Mono.Android", StringComparison.Ordinal);
+		if (aMonoAndroid != bMonoAndroid) {
+			return aMonoAndroid ? -1 : 1;
+		}
+
+		int result = StringComparer.Ordinal.Compare (a.ManagedTypeName, b.ManagedTypeName);
+		return result != 0 ? result : StringComparer.Ordinal.Compare (a.AssemblyName, b.AssemblyName);
+	}
+
 	static void EmitPeers (TypeMapAssemblyData model, string jniName,
 		List<JavaPeerInfo> peersForName, string assemblyName, HashSet<string> usedProxyNames)
 	{

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

@@ -1,11 +1,13 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Reflection.Metadata;
 using System.Reflection.Metadata.Ecma335;
 using System.Reflection.PortableExecutable;
+using System.Security.Cryptography;
 
 namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 
@@ -107,12 +109,28 @@ public void WritePE (Stream stream)
 			new PEHeaderBuilder (imageCharacteristics: Characteristics.Dll),
 			new MetadataRootBuilder (Metadata),
 			ILBuilder,
-			mappedFieldData: _mappedFieldData.Count > 0 ? _mappedFieldData : null);
+			mappedFieldData: _mappedFieldData.Count > 0 ? _mappedFieldData : null,
+			// ManagedPEBuilder otherwise uses a time-based id, changing bytes on every regeneration.
+			deterministicIdProvider: DeterministicContentId);
 		var peBlob = new BlobBuilder ();
 		peBuilder.Serialize (peBlob);
 		peBlob.WriteContentTo (stream);
 	}
 
+	static BlobContentId DeterministicContentId (IEnumerable<Blob> content)
+	{
+		using var hash = IncrementalHash.CreateHash (HashAlgorithmName.SHA256);
+		foreach (var blob in content) {
+			var segment = blob.GetBytes ();
+			if (segment.Count == 0) {
+				continue;
+			}
+			Debug.Assert (segment.Array is not null);
+			hash.AppendData (segment.Array, segment.Offset, segment.Count);
+		}
+		return BlobContentId.FromHash (hash.GetHashAndReset ());
+	}
+
 	/// <summary>
 	/// Adds (or retrieves from cache) an assembly reference.
 	/// </summary>

src/Microsoft.Android.Sdk.TrimmableTypeMap/ITrimmableTypeMapLogger.cs

@@ -13,6 +13,7 @@ public interface ITrimmableTypeMapLogger
 	void LogRootingManifestReferencedTypeInfo (string javaTypeName, string managedTypeName);
 	void LogManifestReferencedTypeNotFoundWarning (string javaTypeName);
 	void LogLibraryManifestMergeWarning (string message);
+	void LogInvalidManifestPlaceholderWarning (string placeholders);
 	void LogUnresolvableJavaPeerSkippedWarning (
 		string managedTypeName,
 		string assemblyName,

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

@@ -164,6 +164,7 @@ bool TryGetTypeReferenceAssemblyName (TypeReference typeReference, [NotNullWhen
 		// with the wrong AttributeName.
 		List<IntentFilterInfo>? intentFilters = null;
 		List<MetaDataInfo>? metaData = null;
+		Dictionary<string, object?>? layoutProperties = null;
 
 		foreach (var caHandle in typeDef.GetCustomAttributes ()) {
 			var ca = Reader.GetCustomAttribute (caHandle);
@@ -214,6 +215,8 @@ bool TryGetTypeReferenceAssemblyName (TypeReference typeReference, [NotNullWhen
 				metaData ??= new List<MetaDataInfo> ();
 				var (mdName, mdProps) = ParseNameAndProperties (ca);
 				metaData.Add (CreateMetaDataInfo (mdName, mdProps));
+			} else if (attrName == "LayoutAttribute") {
+				layoutProperties = ParseLayoutAttribute (ca);
 			} else if (attrInfo is null && ImplementsJniNameProviderAttribute (ca)) {
 				// Custom attribute implementing IJniNameProviderAttribute (e.g., user-defined [CustomJniName])
 				var name = TryGetNameProperty (ca);
@@ -232,6 +235,9 @@ bool TryGetTypeReferenceAssemblyName (TypeReference typeReference, [NotNullWhen
 			if (metaData is not null) {
 				attrInfo.MetaData.AddRange (metaData);
 			}
+			if (layoutProperties is not null) {
+				attrInfo.LayoutProperties = layoutProperties;
+			}
 		}
 
 		return (registerInfo, attrInfo);
@@ -425,6 +431,18 @@ RegisterInfo ParseRegisterInfo (CustomAttributeValue<string> value)
 		return null;
 	}
 
+	Dictionary<string, object?> ParseLayoutAttribute (CustomAttribute ca)
+	{
+		var value = DecodeAttribute (ca);
+		var properties = new Dictionary<string, object?> (StringComparer.Ordinal);
+		foreach (var named in value.NamedArguments) {
+			if (named.Name is not null) {
+				properties [named.Name] = named.Value;
+			}
+		}
+		return properties;
+	}
+
 	IntentFilterInfo ParseIntentFilterAttribute (CustomAttribute ca)
 	{
 		var value = DecodeAttribute (ca);
@@ -712,6 +730,12 @@ class TypeAttributeInfo (string attributeName)
 	/// Metadata entries declared on this type via [MetaData] attributes.
 	/// </summary>
 	public List<MetaDataInfo> MetaData { get; } = [];
+
+	/// <summary>
+	/// Named property values from a [Layout] attribute on this type, or null if none.
+	/// Maps to the &lt;layout&gt; child element of the component in the manifest.
+	/// </summary>
+	public Dictionary<string, object?>? LayoutProperties { get; set; }
 }
 
 sealed class ApplicationAttributeInfo () : TypeAttributeInfo ("ApplicationAttribute")

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

@@ -274,6 +274,10 @@ static void ForceUnconditionalIfPresent (Dictionary<(string ManagedName, string
 		}
 	}
 
+	// ManagedPeer depends on reflection-based registration; the trimmable path uses IAndroidCallableWrapper.
+	static bool IsUnsupportedByTrimmableTypeMap (string managedFullName, string assemblyName) =>
+		managedFullName == "Java.Interop.ManagedPeer" && assemblyName == "Java.Interop";
+
 	void ScanAssembly (AssemblyIndex index, Dictionary<(string ManagedName, string AssemblyName), JavaPeerInfo> results)
 	{
 		foreach (var typeHandle in index.Reader.TypeDefinitions) {
@@ -286,6 +290,10 @@ void ScanAssembly (AssemblyIndex index, Dictionary<(string ManagedName, string A
 
 			var fullName = MetadataTypeNameResolver.GetFullName (typeDef, index.Reader);
 
+			if (IsUnsupportedByTrimmableTypeMap (fullName, index.AssemblyName)) {
+				continue;
+			}
+
 			// Temporarily allow [JniAddNativeMethodRegistrationAttribute] while we investigate
 			// which scenarios fail later in the trimmable typemap pipeline.
 			// if (index.MayUseJniAddNativeMethodRegistrationAttribute &&
@@ -2528,6 +2536,7 @@ void CollectExportField (MethodDefinition methodDef, AssemblyIndex index, List<J
 			Properties = attrInfo.Properties,
 			IntentFilters = attrInfo.IntentFilters,
 			MetaData = attrInfo.MetaData,
+			LayoutProperties = attrInfo.LayoutProperties,
 		};
 	}
 }

src/Microsoft.Android.Sdk.TrimmableTypeMap/TrimmableTypeMapGenerator.cs

@@ -155,6 +155,7 @@ GeneratedManifest GenerateManifest (List<JavaPeerInfo> allPeers, AssemblyManifes
 				// Other codes (e.g. unresolvable type properties) are not yet assigned XA codes
 				// and are intentionally not surfaced here.
 			},
+			WarnInvalidPlaceholder = placeholders => logger.LogInvalidManifestPlaceholderWarning (placeholders),
 			LibraryManifests = config.LibraryManifests ?? [],
 		};
 

src/Xamarin.Android.Build.Tasks/Tasks/GenerateTrimmableTypeMap.cs

@@ -46,6 +46,8 @@ public void LogManifestReferencedTypeNotFoundWarning (string javaTypeName) =>
 			log.LogCodedWarning ("XA4250", Properties.Resources.XA4250, javaTypeName);
 		public void LogLibraryManifestMergeWarning (string message) =>
 			log.LogCodedWarning ("XA4302", Properties.Resources.XA4302, message);
+		public void LogInvalidManifestPlaceholderWarning (string placeholders) =>
+			log.LogCodedWarning ("XA1010", Properties.Resources.XA1010, placeholders);
 		public void LogUnresolvableJavaPeerSkippedWarning (
 			string managedTypeName,
 			string assemblyName,

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

@@ -105,6 +105,25 @@ public void Placeholders_AllValid_DoesNotWarn ()
 		Assert.Equal ("val1", (string?) doc.Root?.Element ("application")?.Attribute (AndroidNs + "label"));
 	}
 
+	[Fact]
+	public void Placeholders_EmptyKey_ReplacesEmptyTokenWithoutWarning ()
+	{
+		var gen = CreateDefaultGenerator ();
+		var warnings = new List<string> ();
+		gen.WarnInvalidPlaceholder = warnings.Add;
+		gen.ManifestPlaceholders = "=val1";
+		var template = ParseTemplate ("""
+			<?xml version="1.0" encoding="utf-8"?>
+			<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.app">
+			  <uses-sdk />
+			  <application android:label="${}" />
+			</manifest>
+			""");
+		var doc = GenerateAndLoad (gen, template: template);
+		Assert.Empty (warnings);
+		Assert.Equal ("val1", (string?) doc.Root?.Element ("application")?.Attribute (AndroidNs + "label"));
+	}
+
 	[Fact]
 	public void Package_PlaceholderToken_ReplacedWithResolvedPackageName ()
 	{
@@ -385,6 +404,24 @@ public void Activity_LayoutAttributeElement ()
 		Assert.Equal ("400dp", (string?)layout?.Attribute (AndroidNs + "minHeight"));
 	}
 
+	[Fact]
+	public void Service_LayoutAttributeElement_Ignored ()
+	{
+		var gen = CreateDefaultGenerator ();
+		var peer = CreatePeer ("com/example/app/MyService", new ComponentInfo {
+			Kind = ComponentKind.Service,
+			LayoutProperties = new Dictionary<string, object?> {
+				["DefaultWidth"] = "500dp",
+			},
+		});
+
+		var doc = GenerateAndLoad (gen, [peer]);
+		var service = doc.Root?.Element ("application")?.Element ("service");
+
+		Assert.NotNull (service);
+		Assert.Null (service?.Element ("layout"));
+	}
+
 	[Fact]
 	public void Activity_AllExtendedProperties ()
 	{

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

@@ -38,6 +38,8 @@ public void LogManifestReferencedTypeNotFoundWarning (string javaTypeName) =>
 			warnings?.Add ($"Manifest-referenced type '{javaTypeName}' was not found in any scanned assembly. It may be a framework type.");
 		public void LogLibraryManifestMergeWarning (string message) =>
 			warnings?.Add (message);
+		public void LogInvalidManifestPlaceholderWarning (string placeholders) =>
+			warnings?.Add ($"Invalid $(AndroidManifestPlaceholders) '{placeholders}'.");
 		public void LogUnresolvableJavaPeerSkippedWarning (
 			string managedTypeName,
 			string assemblyName,

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

@@ -113,6 +113,23 @@ public void Build_ThreeWayAlias_CreatesCorrectIndexedEntries ()
 			Assert.Equal (3, model.AliasHolders [0].AliasKeys.Count);
 		}
 
+		[Fact]
+		public void Build_AliasGroup_MonoAndroidPeerSortsFirst ()
+		{
+			// Java.Interop first proves Mono.Android still becomes alias [0], matching runtime lookup.
+			var peers = new List<JavaPeerInfo> {
+				MakeMcwPeer ("java/lang/Object", "Java.Interop.JavaObject", "Java.Interop") with { IsFromJniTypeSignature = true },
+				MakeMcwPeer ("java/lang/Object", "Java.Lang.Object", "Mono.Android"),
+			};
+
+			var model = BuildModel (peers, "MonoAndroid");
+
+			Assert.Equal ("java/lang/Object[0]", model.Entries [0].MapKey);
+			Assert.Contains ("Java.Lang.Object", model.Entries [0].ProxyTypeReference);
+			Assert.Equal ("java/lang/Object[1]", model.Entries [1].MapKey);
+			Assert.Contains ("Java.Interop.JavaObject", model.Entries [1].ProxyTypeReference);
+		}
+
 		[Fact]
 		public void Build_AliasWithMixedActivation_PrimaryNoActivation_AliasHasActivation ()
 		{