[TrimmableTypeMap] Propagate deferred registerNatives to base classes

[simonrozsival]

Summary

Fixes a startup crash (UnsatisfiedLinkError: No implementation found for void mono.android.Runtime.registerNatives) when running device tests with the trimmable typemap enabled.

Background

Deferred registerNatives support was introduced across several PRs:

• [TrimmableTypeMap] Skip registerNatives for Application/Instrumentation types #10957 — Added CannotRegisterInStaticConstructor flag and set it in JavaPeerScanner for types with [Application] or [Instrumentation] attributes. The JCW generator skips the static { registerNatives(...); } block for these types and emits a lazy __md_registerNatives() helper instead.
• [TrimmableTypeMap] Root AndroidManifest-referenced types #11037 — Extended deferred registration to manifest-rooted types: RootManifestReferencedTypes sets CannotRegisterInStaticConstructor on types matched by <application> or <instrumentation> manifest entries.
• [TrimmableTypeMap] Scanner and JCW edge-case fixes #11096 / [TrimmableTypeMap] Manifest rooting and deferred registration propagation #11097 — Further scanner and JCW edge-case fixes, including deferred registration propagation for generated managed base types.

None of these PRs propagated the flag to base classes in the Java type hierarchy. When NUnitInstrumentation (listed in the manifest) correctly uses deferred registration, its base class TestInstrumentation_1 still emits static { registerNatives(...); }. Since Java loads the base class <clinit> before the managed runtime registers the JNI native method, this crashes with UnsatisfiedLinkError.

Changes

Add PropagateDeferredRegistrationToBaseClasses() in TrimmableTypeMapGenerator, called after RootManifestReferencedTypes. It walks each flagged peer's BaseJavaName chain with a simple linear scan and sets CannotRegisterInStaticConstructor = true on all base peers that have JCW stubs (i.e., !DoNotGenerateAcw). Framework MCW types are skipped.

In practice only 1–2 types need propagation (one Application, maybe one Instrumentation), each with a short base-class chain. A linear scan per ancestor is simpler and cheaper than building a Dictionary<JavaName, List<Peer>> lookup over all peers up front.

Test

New unit test PropagateDeferredRegistrationToBaseClasses_PropagatesToBaseClassesOfManifestReferencedTypes verifies a 3-level instrumentation hierarchy (base → mid → leaf) where only the leaf is in the manifest. After propagation, all three peers have deferred registration.

All 353 existing unit tests continue to pass.

[Copilot]

Pull request overview

Fixes a startup crash in trimmable typemap device tests by ensuring deferred Runtime.registerNatives() behavior is applied not only to manifest-rooted peers (e.g., Instrumentation) but also to their Java base classes, preventing premature base-class <clinit> registration.

Changes:

• Invoke a new deferred-registration propagation step after manifest rooting in TrimmableTypeMapGenerator.Execute().
• Add PropagateDeferredRegistrationToBaseClasses() to walk BaseJavaName chains and mark base peers for deferred registration.
• Add a unit test covering a 3-level instrumentation hierarchy where only the leaf is manifest-rooted.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/Microsoft.Android.Sdk.TrimmableTypeMap/TrimmableTypeMapGenerator.cs	Adds and wires up deferred-registration propagation across base Java peers.
tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Generator/TrimmableTypeMapGeneratorTests.cs	Adds regression coverage for deferred-registration propagation across a base chain.

[simonrozsival]

🤖 AI Review Summary

Verdict: ✅ LGTM

Clean, focused fix for a real startup crash. The change is minimal — one new method + one test — and the linear scan approach is well-justified given the tiny number of types that need propagation.

Found 1 suggestion:

• 💡 Performance: The string != comparison in the inner loop could use StringComparison.Ordinal for explicit intent (TrimmableTypeMapGenerator.cs:234)

👍 Good things:

• Excellent PR description tracing the history of deferred registration across PRs
• XML doc comment on the method clearly explains the "why"
• The inline comment explaining the linear scan vs dictionary trade-off is helpful for future readers
• Test covers a 3-level hierarchy with assertions both before and after propagation — good boundary verification

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Review generated by android-reviewer from review guidelines.