Function attachExitHandler

packages/cli/src/subprocess.ts:134–169

* Handle process exit — attempt one auto-restart, then switch to file-watch * mode so the server restarts as soon as the agent (or user) saves a fix.

(child: ResultPromise)

 * mode so the server restarts as soon as the agent (or user) saves a fix.
 */
function attachExitHandler(child: ResultPromise) {
    child.catch(async (error) => {
        // Don't auto-restart if we're intentionally stopping or restarting
        if (state.status === 'restarting' || state.status === 'stopped') return;

        state.status = 'crashed';
        state.lastError = error instanceof Error ? error.message : String(error);
        awel.error(`Dev server crashed: ${state.lastError}`);

        if (!autoRestartEnabled) return;

        state.restartCount++;

        // First crash: try one immediate auto-restart (could be a transient issue)
        if (state.restartCount <= 1) {
            const delay = getBackoffDelay(state.restartCount);
            awel.log(`Auto-restarting dev server in ${delay}ms (attempt ${state.restartCount})...`);
            await new Promise(r => setTimeout(r, delay));

            if (state.status !== 'crashed') return;

            try {
                await doSpawn();
                awel.log('Dev server auto-restarted successfully.');
                return;
            } catch (err) {
                const msg = err instanceof Error ? err.message : String(err);
                awel.error(`Auto-restart failed: ${msg}`);
            }
        }

        // Repeated crashes: stop retrying blindly, watch for file changes instead
        awel.log('Watching for file changes to restart dev server...');
        startCrashWatcher();
    });
}

/**
 * Internal spawn + health-check routine.