/**
 * Deadline guards for filesystem work that can land on a network mount.
 *
 * Inside the agent container `/skaile/workspace` **is** an rclone FUSE mount
 * (SharePoint / OneDrive / WebDAV). When the host rclone process wedges, a
 * filesystem call against that path parks in an uninterruptible kernel wait.
 * A **synchronous** call there stops the entire single-threaded event loop —
 * the whole `skaile serve` process stops serving, and the platform reads the
 * session as dead or idle. A hang is not an error, so `try/catch` never fires.
 *
 * Two rules follow, and both matter:
 *
 * 1. **Never touch a mount synchronously.** Async `node:fs/promises` keeps the
 *    loop free, so a wedged mount degrades to one stuck request instead of a
 *    dead session. This is the actual fix.
 * 2. **Bound the wait.** {@link withFsDeadline} converts an unbounded wait into
 *    a bounded failure so the requester gets an error rather than nothing.
 *
 * `withFsDeadline` does **not** cancel the underlying operation — Node cannot
 * abort a syscall already in the kernel. The losing promise stays pending until
 * the mount recovers or the process exits. That is acceptable precisely because
 * rule 1 holds: a pending promise costs one handle, not the event loop.
 *
 * Modelled on `connectors/src/fleet-utils.ts` (`ensureFleetMounted`), which
 * already does async-stat-with-deadline correctly.
 */
/** Default deadline for a single filesystem operation on a possibly-networked mount. */
export declare const DEFAULT_FS_DEADLINE_MS = 15000;
/**
 * Env override for {@link DEFAULT_FS_DEADLINE_MS}, in milliseconds.
 *
 * A cloud-backed mount over a slow link can legitimately need longer than the
 * default; operators raise this rather than patching call sites.
 */
export declare const FS_DEADLINE_ENV_VAR = "SKAILE_FS_DEADLINE_MS";
/**
 * Thrown when a filesystem operation misses its deadline.
 *
 * Distinct from a plain `Error` so callers can tell "the mount is wedged" apart
 * from "the file does not exist" and surface the right message to the frontend.
 */
export declare class FsDeadlineError extends Error {
    readonly timeoutMs: number;
    readonly operation: string;
    constructor(operation: string, timeoutMs: number);
}
/**
 * Resolve the effective filesystem deadline.
 *
 * Reads {@link FS_DEADLINE_ENV_VAR} on every call rather than caching it: the
 * runner mutates `process.env` while wiring a session, so a module-load-time
 * snapshot would pin the value set before configuration ran.
 *
 * @param fallback - Deadline to use when the env var is absent or unusable.
 * @returns The deadline in milliseconds.
 */
export declare function fsDeadlineMs(fallback?: number): number;
/**
 * Run an async filesystem operation under a deadline.
 *
 * @param operation - Short label used in the timeout message (e.g. `"readdir /skaile/workspace"`).
 * @param fn - Thunk performing the operation. Called immediately.
 * @param timeoutMs - Deadline override; defaults to {@link fsDeadlineMs}.
 * @returns The operation's result.
 * @throws {FsDeadlineError} when the deadline elapses first.
 * @throws Whatever `fn` rejects with, unchanged, when it loses no race.
 * @docLink packages/core/api-reference#with-fs-deadline
 */
export declare function withFsDeadline<T>(operation: string, fn: () => Promise<T>, timeoutMs?: number): Promise<T>;
/**
 * Run an async filesystem operation under a deadline, mapping every failure to
 * `fallback`.
 *
 * For best-effort probes that previously used `existsSync` — a missing file, an
 * unreadable file, and a wedged mount are all "nothing usable here", and the
 * caller has no better move than to continue without it.
 *
 * @param operation - Short label used in the timeout message.
 * @param fn - Thunk performing the operation.
 * @param fallback - Value returned when `fn` rejects or the deadline elapses.
 * @param timeoutMs - Deadline override; defaults to {@link fsDeadlineMs}.
 */
export declare function tryWithFsDeadline<T>(operation: string, fn: () => Promise<T>, fallback: T, timeoutMs?: number): Promise<T>;
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