Function readBridgePointer

src/bridge/bridgePointer.ts:83–113

(
  dir: string,
)

 * keep re-prompting after the backend has already GC'd the env.
 */
export async function readBridgePointer(
  dir: string,
): Promise<(BridgePointer & { ageMs: number }) | null> {
  const path = getBridgePointerPath(dir)
  let raw: string
  let mtimeMs: number
  try {
    // stat for mtime (staleness anchor), then read. Two syscalls, but both
    // are needed — mtime IS the data we return, not a TOCTOU guard.
    mtimeMs = (await stat(path)).mtimeMs
    raw = await readFile(path, 'utf8')
  } catch {
    return null
  }

  const parsed = BridgePointerSchema().safeParse(safeJsonParse(raw))
  if (!parsed.success) {
    logForDebugging(`[bridge:pointer] invalid schema, clearing: ${path}`)
    await clearBridgePointer(dir)
    return null
  }

  const ageMs = Math.max(0, Date.now() - mtimeMs)
  if (ageMs > BRIDGE_POINTER_TTL_MS) {
    logForDebugging(`[bridge:pointer] stale (>4h mtime), clearing: ${path}`)
    await clearBridgePointer(dir)
    return null
  }

  return { ...parsed.data, ageMs }
}

/**
 * Worktree-aware read for `--continue`. The REPL bridge writes its pointer