MapsInLazyColumnActivity hangs the demo app in DemoAppSmokeTest on a Pixel 4 (Android 13) #1070

Summary

Running the demo smoke tests on a physical Pixel 4, DemoAppSmokeTest.demoLaunchesAndShowsMap[MapsInLazyColumnActivity] hangs the app and Android shows "android-maps-compose isn't responding". It happened in two separate runs, always on that demo and nowhere else. The same suite passes on the API 36 emulator in CI.

Environment

• Pixel 4, Android 13 (build TP1A.221005.002.B2), Google Play services 26.43.30
• main at 174f0fd, :maps-app:connectedDebugAndroidTest with requireMapLoaded=true
• Found while testing test: use the v2 Compose test rules in the maps-app instrumentation tests #1069; it does not depend on it, DemoAppSmokeTest does not use the Compose test rule

What the ANR traces show

Both ANRs are on MapsInLazyColumnActivity (11:17 and 11:48), reported when the screen turned off/on and the app could not handle the broadcast.

• The test runner thread is waiting on the main thread at DemoAppSmokeTest.kt:137: in the first run in ActivityScenario.close() (Instrumentation.waitForIdleSync), in the second one in ActivityScenario.launch() (Instrumentation.startActivitySync).
• There is no "main" thread in the dump of the app process. The tid=1 slot belongs to a binder thread (binder:25311_7), while the original main thread (sysTid = pid) is still alive, blocked in futex_wait_queue_me. So the main thread is no longer attached to the runtime, which is what happens when it ends after an uncaught exception.
• DemoAppSmokeTest replaces the default uncaught exception handler with one that only records the exception (setUp, lines 118-120). If the main thread throws, the process does not crash: the main thread just stops, and the app hangs until the ANR.
• LeakCanary-Heap-Dump was idle in both dumps, so it is not a heap dump freezing the app.

Launching MapsInLazyColumnActivity by hand on the same phone (without the test handler) works: it loads and stays alive, with no crash in logcat. The only thing logged is Play services saying MapView.onCreate blocked the main thread for 143 ms, which is expected.

Open questions

• What the exception on the main thread is. The handler swallows it and the test hangs before assertNoUncaughtExceptions() can report it. Since it only happens under the test, the fast launch/close is the main suspect (several MapViews created and destroyed inside a LazyColumn).
• Whether it reproduces on other devices or Android versions.

Proposal

1. Make the test handler also log the throwable (or delegate to the original handler for the main thread), so the exception shows up in logcat and the test fails with it instead of hanging.
2. Re-run on the Pixel 4 to get the actual exception, then fix MapsInLazyColumnActivity or the library code behind it.