feat(react-native): detect and report Android ANRs

[KishanPRao]

Summary

Adds Android ANR detection with two modes, a threshold watchdog that reports mid-hang and ApplicationExitInfo records reported on the next launch, both carrying every thread's stack.

Changes

packages/react-native/src

• BacktraceConfiguration.ts: adds the BacktraceAnrType enum and anr configuration options.
• BacktraceClient.ts: starts ANR reporting on initialize, picks watchdog or exit-info by type, disposes the handler.
• anr/AnrWatchdogHandler.ts: turns watchdog events into reports with main as the faulting thread and every other thread included, pauses the watchdog while backgrounded.
• anr/AnrReporter.ts: reads exit-info records on launch, sends oldest first, saves the last-timestamp cursor when a report is delivered or stored in the database for retry, attaches the OS dump.
• anr/AnrThreads.ts: attaches the non-main threads to a report, renaming duplicate thread names.
• anr/AnrException.ts: error named Hang for classification.
• index.ts: exports the new enum and config type.

packages/react-native/android

• BacktraceAnrWatchdog.java: native module, starts/stops the watchdog, emits detection events with frames for every thread.
• BacktraceReactNative.java: adds getAnrExitInfo, logs read failures at warn.
• ReactNativePackage.java: registers the watchdog module.
• AnrExitInfoReader.java: collects REASON_ANR records, returns them oldest first with attributes, message, raw trace, and parsed frames for the main thread and every other thread in the dump.
• anr/AnrWatchdog.java: watchdog thread, posts a ticker to the main looper, reports when the tick is missed past the timeout, one report per hang, optional debugger bail-out.
• anr/BacktraceThreadWatcher.java: tick counters the watchdog compares.
• anr/ExitInfo.java: ported from backtrace-android.
• anr/ExitInfoAdapter.java: ported from backtrace-android.
• anr/ProcessExitInfoProvider.java: ported from backtrace-android.
• anr/ActivityManagerExitInfoProvider.java: exit-record lookup, fetches all records instead of a fixed count.
• anr/ExitInfoStackTraceParser.java: parses the OS ANR dump into per-thread frames, keeps native-method, unknown-source, and fileless frames, null-guards unnamed threads.
• anr/AppExitInfoDetailsExtractor.java: extracts the ANR attributes and OS trace, attribute names match backtrace-android.
• anr/StackFrameMapper.java: maps stack traces to bridge frames and formatted text, keeps the native program counter as address.
• build.gradle: adds junit for unit tests.

Tests

• tests/anrReporterTests.spec.ts: covers ordering, cursor advancement, database-stored failures, attributes, attachment.
• tests/anrWatchdogHandlerTests.spec.ts: covers event handling, thread-name dedup, background pause, dispose.
• android/src/test/ExitInfoStackTraceParserTest.java: parser tests over a real ANR dump, covering the fileless and duplicate-name forms.
• android/src/test/resources/anrAppExitInfoStacktrace.txt: the dump fixture.

Docs and CI

• README.md: ANR Detection section.
• .github/workflows/android.yml: runs the SDK unit tests before the emulator build.

examples/sdk/reactNative

• index.js: enables ANR in the example.
• metro.config.js: pins a single react-native copy, a duplicate splits the JS event registry from the native one.
• ErrorGenerator.java: adds blockMainThread to trigger a real ANR.
• src/actions/android/action.ts: the ANR action blocks the main thread instead of sleeping async.

Note

A threshold report can be lost if the OS kills the app before the hang clears; the applicationExit type survives the kill.

ref: BT-7451

[melekr]

🚀