[TrimmableTypeMap] Generator correctness fixes

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

@@ -98,9 +98,22 @@ 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
+			// Order aliases to match the java→managed selection the native runtime performs (see
+			// clr_typemap_java_to_managed / monovm_typemap_java_to_managed and NativeTypeMappingData):
+			// the runtime builds its java→managed map by processing the Mono.Android module first and
+			// keeping the first managed type that claims a Java name (first-writer-wins). GetTypeForSimpleReference
+			// returns the first (index [0]) alias, so put the Mono.Android peer first — e.g. java/lang/Object
+			// must resolve to Java.Lang.Object (Mono.Android), not Java.Interop.JavaObject. Remaining peers are
+			// ordered by ordinal managed type name for deterministic proxy naming.
 			if (peersForName.Count > 1) {
-				peersForName.Sort ((a, b) => StringComparer.Ordinal.Compare (a.ManagedTypeName, b.ManagedTypeName));
+				peersForName.Sort ((a, b) => {
+					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;
+					}
+					return StringComparer.Ordinal.Compare (a.ManagedTypeName, b.ManagedTypeName);
+				});
 			}
 
 			EmitPeers (model, jniName, peersForName, assemblyName, usedProxyNames);

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

@@ -6,6 +6,7 @@
 using System.Reflection.Metadata;
 using System.Reflection.Metadata.Ecma335;
 using System.Reflection.PortableExecutable;
+using System.Security.Cryptography;
 
 namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 
@@ -107,12 +108,28 @@ 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,
+			// Derive the PE content id (and thus the header TimeDateStamp/debug id) from a hash of the
+			// image so the bytes are fully deterministic. Without this, ManagedPEBuilder falls back to a
+			// time-based id, so every regeneration produces different bytes even for identical input; that
+			// churns the generated typemap assemblies and breaks incremental packaging (a no-op rebuild
+			// re-touches the .dll, forcing repackage + re-sign). The MVID is already deterministic.
+			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 ();
+			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

@@ -12,6 +12,7 @@ public interface ITrimmableTypeMapLogger
 	void LogGeneratedJcwFilesInfo (int sourceCount);
 	void LogRootingManifestReferencedTypeInfo (string javaTypeName, string managedTypeName);
 	void LogManifestReferencedTypeNotFoundWarning (string javaTypeName);
+	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 +274,13 @@ static void ForceUnconditionalIfPresent (Dictionary<(string ManagedName, string
 		}
 	}
 
+	// Managed types that must never be emitted into the trimmable type map, keyed by
+	// (managed full name, assembly simple name). These are reflection-based ([RequiresUnreferencedCode])
+	// helpers that the trimmable runtime never activates via the type map; emitting proxies for them
+	// only produces IL2026 trim warnings.
+	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 +293,16 @@ void ScanAssembly (AssemblyIndex index, Dictionary<(string ManagedName, string A
 
 			var fullName = MetadataTypeNameResolver.GetFullName (typeDef, index.Reader);
 
+			// Java.Interop.ManagedPeer is a reflection-based helper (marked
+			// [RequiresUnreferencedCode]) that is not supported by the trimmable type map: on the
+			// trimmable path native registration goes through IAndroidCallableWrapper.RegisterNatives
+			// and ManagedPeerNativeRegistration is disabled, so ManagedPeer is never activated via the
+			// type map. Emitting a proxy for it only produces IL2026 trim warnings (its constructors
+			// use reflection), so exclude it here.
+			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 +2545,7 @@ 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

@@ -149,6 +149,7 @@ GeneratedManifest GenerateManifest (List<JavaPeerInfo> allPeers, AssemblyManifes
 			ForceExtractNativeLibs = forceDebuggable,
 			ManifestPlaceholders = config.ManifestPlaceholders,
 			ApplicationJavaClass = config.ApplicationJavaClass,
+			WarnInvalidPlaceholder = placeholders => logger.LogInvalidManifestPlaceholderWarning (placeholders),
 		};
 
 		var (doc, providerNames) = generator.Generate (manifestTemplate, allPeers, assemblyManifestInfo);

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

@@ -44,6 +44,8 @@ public void LogRootingManifestReferencedTypeInfo (string javaTypeName, string ma
 			log.LogMessage (MessageImportance.Low, $"Rooting manifest-referenced type '{javaTypeName}' ({managedTypeName}) as unconditional.");
 		public void LogManifestReferencedTypeNotFoundWarning (string javaTypeName) =>
 			log.LogCodedWarning ("XA4250", Properties.Resources.XA4250, javaTypeName);
+		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/TrimmableTypeMapGeneratorTests.cs

@@ -36,6 +36,8 @@ public void LogRootingManifestReferencedTypeInfo (string javaTypeName, string ma
 			logMessages.Add ($"Rooting manifest-referenced type '{javaTypeName}' ({managedTypeName}) as unconditional.");
 		public void LogManifestReferencedTypeNotFoundWarning (string javaTypeName) =>
 			warnings?.Add ($"Manifest-referenced type '{javaTypeName}' was not found in any scanned assembly. It may be a framework type.");
+		public void 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 +113,29 @@ public void Build_ThreeWayAlias_CreatesCorrectIndexedEntries ()
 			Assert.Equal (3, model.AliasHolders [0].AliasKeys.Count);
 		}
 
+		[Fact]
+		public void Build_AliasGroup_MonoAndroidPeerSortsFirst ()
+		{
+			// Mirror the native runtime's java→managed selection (clr_typemap_java_to_managed /
+			// monovm_typemap_java_to_managed): NativeTypeMappingData builds that map by processing the
+			// Mono.Android module first and keeping the first managed type to claim a Java name, so
+			// java/lang/Object resolves to Java.Lang.Object (Mono.Android), not Java.Interop.JavaObject
+			// (Java.Interop). GetTypeForSimpleReference returns alias index [0], so the Mono.Android peer
+			// must sort first. Declare them in the "wrong" order to prove the sort reorders them.
+			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");
+
+			// The Mono.Android peer (Java.Lang.Object) must be alias index [0].
+			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 ()
 		{