microsoft/typescript-go · error

GetOverlappedResult failed

Error message

GetOverlappedResult failed

What it means

Terminal error from the Windows run loop: both WaitForSingleObject and GetOverlappedResult failed for a pending overlapped read. The subscription calls fatal(), which removes the watch and delivers the error wrapped with ErrWatchTerminated ('fswatch: watch terminated: GetOverlappedResult failed') on the callback. The watch is dead; no further events are delivered.

Source

Thrown at internal/fswatch/windows.go:108

//     - FILE_ACTION_MODIFIED                  → events.update (→ EventUpdate)
//     - FILE_ACTION_REMOVED / RENAMED_OLD_NAME → events.remove + tree.remove
//  4. Call dirWatch.notify() to trigger the debouncer.
//
// Error recovery:
//   - ERROR_OPERATION_ABORTED → normal shutdown (CancelIoEx was called).
//   - ERROR_INVALID_PARAMETER → shrink buffer to 64 KB (network share limit).
//   - ERROR_NOTIFY_ENUM_DIR  → ErrOverflow (too many changes queued).
//   - ERROR_ACCESS_DENIED    → check if the watched dir was deleted.
//
// Shutdown:
//   close(stopCh) → CancelIoEx cancels in-flight IO → run() goroutine
//   exits → deferred CloseHandle closes the directory handle → doneCh closed.
// ---------------------------------------------------------------------------

var (
	errGetFileInfo         = errors.New("could not get file information")
	errReadChanges         = errors.New("failed to read changes")
	errGetOverlappedResult = errors.New("GetOverlappedResult failed")
	errUnknown             = errors.New("unknown error")
)

const (
	defaultBufSize = 1024 * 1024
	networkBufSize = 64 * 1024

	notifyChangeFilter = windows.FILE_NOTIFY_CHANGE_FILE_NAME |
		windows.FILE_NOTIFY_CHANGE_DIR_NAME |
		windows.FILE_NOTIFY_CHANGE_SIZE |
		windows.FILE_NOTIFY_CHANGE_LAST_WRITE
)

// windowsBackend.
type windowsBackend struct {
	watcherBase
}

View on GitHub (pinned to 1bcfa18d79)

Solutions

1. Handle ErrWatchTerminated in the callback and call Close() on the Watch
2. Re-subscribe after the volume or share is available again
3. For removable media, treat termination as expected and gate re-watching on volume presence
4. Keep derived state rebuildable so a re-watch can rescan the tree

func isWatchTerminated(err error) bool {
    return errors.Is(err, fswatch.ErrWatchTerminated)
}

func(events []fswatch.Event, err error) {
    if errors.Is(err, fswatch.ErrWatchTerminated) {
        watch.Close()
        go resubscribeWhenVolumeReady(dir)
        return
    }
    apply(events)
}

When it happens

Trigger: The directory handle was closed or invalidated while overlapped I/O was pending: drive unmounted, network share dropped, device removed. The wait completed with a failure and the completion query confirmed an error.

Common situations: USB drives unplugged while watched. Mapped drives disconnecting. SMB/iSCSI mounts timing out under load.

Related errors

• could not get file information
• error opening directory: %w
• failed to read changes
• unknown error
• CreateEvent: %w

AI-assisted analysis of microsoft/typescript-go@1bcfa18d79 (2026-08-16). Data as JSON: /api/errors/6e7df449b61d5c22. Report an issue: GitHub.