larksuite/cli · error

local input path must not use a Windows network or device na

Error message

local input path must not use a Windows network or device namespace

What it means

validateLocalInputPlatform rejects input paths using Windows network (UNC \\server\share) or device (\\.\, \\.\pipe) namespaces. Local file I/O in this VFS is restricted to real local filesystem paths; remote/device namespaces require different transports and are blocked up front.

Source

Thrown at internal/vfs/localfileio/path_local_windows.go:39

	}
	cleaned := filepath.Clean(path)
	// A drive-relative path ("C:foo") carries a volume but is not absolute: it
	// resolves against that drive's own current directory, so the location it
	// names is not the one this validation can see. It is also how the stream
	// check below would be slipped, since "C:" is stripped as the volume and
	// the remaining "foo" holds no colon.
	if filepath.VolumeName(cleaned) != "" && !filepath.IsAbs(cleaned) {
		return fmt.Errorf("path must not be drive-relative; give a full path or a path without a drive letter")
	}
	if strings.Contains(cleaned[len(filepath.VolumeName(cleaned)):], ":") {
		return fmt.Errorf("path must not address an NTFS alternate data stream")
	}
	return nil
}

func validateLocalInputPlatform(path string) error {
	if isWindowsNonLocalNamespace(path) {
		return fmt.Errorf("local input path must not use a Windows network or device namespace")
	}

	cleaned := filepath.Clean(path)
	volume := filepath.VolumeName(cleaned)
	remainder := strings.TrimLeft(cleaned[len(volume):], `\/`)
	for _, component := range strings.FieldsFunc(remainder, func(r rune) bool {
		return r == '\\' || r == '/'
	}) {
		if component == "." || component == ".." {
			continue
		}
		if !filepath.IsLocal(component) {
			return fmt.Errorf("local input path contains a reserved Windows path component %q", component)
		}
	}
	return nil
}

View on GitHub (pinned to 7fd6ef3c07)

Solutions

1. Map the UNC share to a drive letter (net use) — note the resulting path must still be absolute, not drive-relative
2. Copy the file to a local directory first and use the local path
3. If a network/device resource is genuinely needed, use the appropriate network-capable API instead of the local FileIO

Example fix

// before
runtime.FileIO().Read(`\\nas\share\config.json`)
// after
runtime.FileIO().Read(`C:\data\config.json`)

func isNonLocalNamespace(p string) bool {
	return strings.HasPrefix(p, `\\`) // UNC (\\server\share) and device (\\.\) namespaces
}

func isLocalDrivePath(p string) bool {
	v := filepath.VolumeName(filepath.Clean(p))
	return v != "" && !strings.HasPrefix(v, `\\`) && filepath.IsAbs(p)
}

When it happens

Trigger: Passing a UNC path like \\fileserver\share\doc.xlsx, a device path \\.\C:\..., or a named pipe \\.\pipe\foo into a local FileIO read/validate call.

Common situations: Pointing the CLI at a network share assumed to behave like a local disk, or attempting to read a device/pipe from a file flag.

Related errors

• %s: cannot stat %q: %w
• cannot stat opened file: %w
• file changed between validation and open
• not a regular file (directories, devices, FIFOs, and sockets
• cannot inspect opened file links: %w

AI-assisted analysis of larksuite/cli@7fd6ef3c07 (2026-09-04). Data as JSON: /api/errors/c53d4b4ddc3cf0b5. Report an issue: GitHub.