detect-native-crashes-and-anrs

Detect crashes the handler can't catch

FireCrasher's onCrash only sees JVM exceptions on threads it controls. Native crashes, ANRs, and low-memory kills terminate the process before any in-process handler runs — they are invisible to it.

On API 30+, Android records these in ApplicationExitInfo. FireCrasher surfaces that record on the next launch so you can report it. All of these return empty/null below API 30, so no version guard is needed in your code.

Option A: the callback (recommended)

Configure onPreviousProcessExit. FireCrasher calls it from install when the system has a record of the app dying abnormally last time:

installFireCrasher {
    onCrash { recover() }

    onPreviousProcessExit { exitInfo ->
        // Only invoked on API 30+; the guard is for lint, which can't see
        // that guarantee through the lambda.
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
            // The record may predate the last launch — check freshness if it matters.
            val recent = System.currentTimeMillis() - exitInfo.timestamp < 60_000
            FirebaseCrashlytics.getInstance().log(
                "previous exit: reason=${exitInfo.reason} desc=${exitInfo.description} recent=$recent"
            )
        }
    }
}

exitInfo.reason values worth branching on include REASON_CRASH, REASON_CRASH_NATIVE, REASON_ANR, and REASON_LOW_MEMORY.

Option B: query directly

Ask for the records from any Context whenever you need them:

// The most recent crash / native crash / ANR, or null.
val lastCrash: ApplicationExitInfo? = lastAbnormalExit()

// Full history, newest first (default up to 16).
val history: List<ApplicationExitInfo> = historicalExitReasons(maxCount = 16)

(From Java: ExitInfoKt.lastAbnormalExit(context) and ExitInfoKt.historicalExitReasons(context, 16).)

Notes

• De-duplicate. The same ApplicationExitInfo record persists across launches. Track the last-seen exitInfo.timestamp (e.g. in SharedPreferences) so you don't report the same death on every launch.
• An ANR record can carry a trace via exitInfo.traceInputStream — attach it to your report when present.
• Below API 30 these APIs no-op; combine this with report-crashes for the JVM exceptions FireCrasher can catch to get full coverage.