Function appendServerCrashLogSync

src/cli/serverCrashLogging.ts:91–115

(options: ServerCrashLogOptions)

}

export function appendServerCrashLogSync(options: ServerCrashLogOptions): string {
  let entry: string;
  try {
    entry = buildServerCrashLogEntry(options);
  } catch (error) {
    // Crash hooks must survive even if the current working directory disappeared
    // or another formatting helper throws while we're already handling a fatal error.
    entry = `${(options.timestamp ?? new Date()).toISOString()} [mux server crash] ${options.event}\nfailed_to_build_crash_entry=${getErrorMessage(error)}\n`;
  }

  const logFilePath = options.logFilePath ?? getLogFilePath();

  // Fatal crashes can terminate the process before the async logger flushes,
  // so server-mode crash hooks append a compact entry synchronously.
  try {
    // eslint-disable-next-line local/no-sync-fs-methods -- crash handlers must create the log directory before the process exits.
    fs.mkdirSync(path.dirname(logFilePath), { recursive: true });
    // eslint-disable-next-line local/no-sync-fs-methods -- synchronous append is intentional so fatal exits still leave a breadcrumb.
    fs.appendFileSync(logFilePath, entry, "utf-8");
  } catch {
    // Best effort: crash logging must never trigger a second failure.
  }

  return entry;
}