[TrimmableTypeMap] Manifest rooting and deferred registration propagation (#11097)

* [TrimmableTypeMap] Manifest rooting and deferred registration propagation

- Manifest name promotion: promote compat JNI names for manifest-rooted
  components so the generated JCW class name matches the manifest entry
- Deferred registration propagation: propagate CannotRegisterInStaticConstructor
  to generated managed base types of Application/Instrumentation
- Instrumentation targetPackage: pass package name for manifest
  instrumentation elements
- XA4250 warning: warn when manifest references a type that cannot be
  resolved in any scanned assembly
- NestedAssembly for UTF-8 helpers: fix FieldAccessException from
  NestedPrivate visibility

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* [TrimmableTypeMap] Address review feedback on manifest rooting

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: simonrozsival

Documentation/docs-mobile/messages/index.md

@@ -207,6 +207,7 @@ Either change the value in the AndroidManifest.xml to match the $(SupportedOSPla
 + [XA4247](xa4247.md): Could not resolve POM file for artifact '{artifact}'.
 + [XA4248](xa4248.md): Could not find NuGet package '{nugetId}' version '{version}' in lock file. Ensure NuGet Restore has run since this `<PackageReference>` was added.
 + [XA4235](xa4249.md): Maven artifact specification '{artifact}' is invalid. The correct format is 'group_id:artifact_id:version'.
++ [XA4250](xa4250.md): Manifest-referenced type '{type}' was not found in any scanned assembly. It may be a framework type.
 + XA4300: Native library '{library}' will not be bundled because it has an unsupported ABI.
 + [XA4301](xa4301.md): Apk already contains the item `xxx`.
 + [XA4302](xa4302.md): Unhandled exception merging \`AndroidManifest.xml\`: {ex}

Documentation/docs-mobile/messages/xa4250.md

@@ -0,0 +1,33 @@
+---
+title: .NET for Android warning XA4250
+description: XA4250 warning code
+ms.date: 04/07/2026
+f1_keywords:
+  - "XA4250"
+---
+
+# .NET for Android warning XA4250
+
+## Example message
+
+Manifest-referenced type '{0}' was not found in any scanned assembly. It may be a framework type.
+
+```text
+warning XA4250: Manifest-referenced type 'com.example.MainActivity' was not found in any scanned assembly. It may be a framework type.
+```
+
+## Issue
+
+The build found a type name in `AndroidManifest.xml`, but it could not match that name to any Java peer discovered in the app's managed assemblies.
+
+This can be expected for framework-provided types, but it can also indicate that the manifest entry does not match the name generated for a managed Android component.
+
+## Solution
+
+If the manifest entry refers to an Android framework type, this warning can usually be ignored.
+
+Otherwise:
+
+1. Verify the `android:name` value in the manifest.
+2. Ensure the managed type is included in the app build.
+3. Check for namespace, `[Register]`, or nested-type naming mismatches between the manifest and the managed type.

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

@@ -165,7 +165,7 @@ internal static void UpdateApplicationElement (XElement app, JavaPeerInfo peer)
 		PropertyMapper.ApplyMappings (app, component.Properties, PropertyMapper.ApplicationElementMappings);
 	}
 
-	internal static void AddInstrumentation (XElement manifest, JavaPeerInfo peer)
+	internal static void AddInstrumentation (XElement manifest, JavaPeerInfo peer, string packageName)
 	{
 		string jniName = JniSignatureHelper.JniNameToJavaName (peer.JavaName);
 		var element = new XElement ("instrumentation",
@@ -176,6 +176,9 @@ internal static void AddInstrumentation (XElement manifest, JavaPeerInfo peer)
 			return;
 		}
 		PropertyMapper.ApplyMappings (element, component.Properties, PropertyMapper.InstrumentationMappings);
+		if (element.Attribute (AndroidNs + "targetPackage") is null && !packageName.IsNullOrEmpty ()) {
+			element.SetAttributeValue (AndroidNs + "targetPackage", packageName);
+		}
 
 		manifest.Add (element);
 	}

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

@@ -73,7 +73,7 @@ class ManifestGenerator
 			}
 
 			if (peer.ComponentAttribute.Kind == ComponentKind.Instrumentation) {
-				ComponentElementBuilder.AddInstrumentation (manifest, peer);
+				ComponentElementBuilder.AddInstrumentation (manifest, peer, PackageName);
 				continue;
 			}
 
@@ -116,10 +116,7 @@ class ManifestGenerator
 		}
 
 		// Apply manifest placeholders
-		string? placeholders = ManifestPlaceholders;
-		if (placeholders is not null && placeholders.Length > 0) {
-			ApplyPlaceholders (doc, placeholders);
-		}
+		ApplyPlaceholders (doc, ManifestPlaceholders);
 
 		return (doc, providerNames);
 	}
@@ -250,8 +247,12 @@ XElement CreateRuntimeProvider (string name, string? processName, int initOrder)
 	/// Replaces ${key} placeholders in all attribute values throughout the document.
 	/// Placeholder format: "key1=value1;key2=value2"
 	/// </summary>
-	static void ApplyPlaceholders (XDocument doc, string placeholders)
+	internal static void ApplyPlaceholders (XDocument doc, string? placeholders)
 	{
+		if (placeholders.IsNullOrEmpty ()) {
+			return;
+		}
+
 		var replacements = new Dictionary<string, string> (StringComparer.Ordinal);
 		foreach (var entry in placeholders.Split (PlaceholderSeparators, StringSplitOptions.RemoveEmptyEntries)) {
 			var eqIndex = entry.IndexOf ('=');

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

@@ -10,4 +10,6 @@ public interface ITrimmableTypeMapLogger
 	void LogGeneratedRootTypeMapInfo (int assemblyReferenceCount);
 	void LogGeneratedTypeMapAssembliesInfo (int assemblyCount);
 	void LogGeneratedJcwFilesInfo (int sourceCount);
+	void LogUnresolvedTypeWarning (string name);
+	void LogRootingManifestReferencedTypeInfo (string name, string managedTypeName);
 }

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

@@ -12,9 +12,11 @@ public sealed record JavaPeerInfo
 {
 	/// <summary>
 	/// JNI type name, e.g., "android/app/Activity".
-	/// Extracted from the [Register] attribute.
+	/// Extracted from the [Register] attribute or auto-computed during scanning.
+	/// Manifest rooting may later promote this to <see cref="CompatJniName"/> when
+	/// a component is referenced by its managed-namespace form.
 	/// </summary>
-	public required string JavaName { get; init; }
+	public required string JavaName { get; set; }
 
 	/// <summary>
 	/// Compat JNI type name, e.g., "myapp.namespace/MyType" for user types (uses raw namespace, not CRC64).
@@ -48,7 +50,7 @@ public sealed record JavaPeerInfo
 	/// that extends Activity. Null for java/lang/Object or types without a Java base.
 	/// Needed by JCW Java source generation ("extends" clause).
 	/// </summary>
-	public string? BaseJavaName { get; init; }
+	public string? BaseJavaName { get; set; }
 
 	/// <summary>
 	/// JNI names of Java interfaces this type implements, e.g., ["android/view/View$OnClickListener"].
@@ -69,16 +71,23 @@ public sealed record JavaPeerInfo
 	/// Types with component attributes ([Activity], [Service], etc.),
 	/// custom views from layout XML, or manifest-declared components
 	/// are unconditionally preserved (not trimmable).
+	/// May be set to <c>true</c> after scanning when the manifest references a type
+	/// that the scanner did not mark as unconditional. Should only ever be set
+	/// to <c>true</c>, never back to <c>false</c>.
 	/// </summary>
-	public bool IsUnconditional { get; init; }
+	public bool IsUnconditional { get; set; }
 
 	/// <summary>
-	/// True for Application and Instrumentation types. These types cannot call
+	/// True for Application and Instrumentation types, plus any generated managed
+	/// base classes they rely on during startup. These types cannot call
 	/// <c>registerNatives</c> in their static initializer because the native library
 	/// (<c>libmonodroid.so</c>) is not loaded until after the Application class is instantiated.
 	/// Registration is deferred to <c>ApplicationRegistration.registerApplications()</c>.
+	/// This may also be set after scanning when a type is only discovered from
+	/// manifest <c>android:name</c> usage on <c>&lt;application&gt;</c> or
+	/// <c>&lt;instrumentation&gt;</c>.
 	/// </summary>
-	public bool CannotRegisterInStaticConstructor { get; init; }
+	public bool CannotRegisterInStaticConstructor { get; set; }
 
 	/// <summary>
 	/// Marshal methods: methods with [Register(name, sig, connector)], [Export], or