Function describeFatal

src/bin/fatal-handler.ts:40–54

(value: unknown)

 * formatting. Pure and total — never throws, never touches `.stack`.
 */
export function describeFatal(value: unknown): string {
  if (value instanceof Error) {
    const name = typeof value.name === 'string' && value.name ? value.name : 'Error';
    // `message` is a plain own/proto string property — reading it does NOT
    // format the stack (which is what can loop forever, #850).
    const message = typeof value.message === 'string' ? value.message : '';
    return message ? `${name}: ${message}` : name;
  }
  try {
    return String(value);
  } catch {
    // e.g. an object with a throwing `toString` / `Symbol.toPrimitive`.
    return '<unstringifiable value>';
  }
}

/** Best-effort synchronous stderr write that can never keep a doomed process alive. */
function writeStderr(line: string): void {