if s == "" || os.IsPathSeparator(s[len(s)-1]) {
		return s
	}
	return s + string(filepath.Separator)
}

// QuoteGlob returns s with all Glob metacharacters quoted.
// We don't try to handle backslash here, as that can appear in a
// file path on Windows.
func QuoteGlob(s string) string {
	if !strings.ContainsAny(s, `*?[]`) {
		return s
	}
	var sb strings.Builder
	for _, c := range s {
		switch c {

	// active.
	parentDir := filepath.Dir(dir)
	tmpPrefix := filepath.Base(dir) + ".tmp-"
	if old, err := filepath.Glob(filepath.Join(str.QuoteGlob(parentDir), str.QuoteGlob(tmpPrefix)+"*")); err == nil {
		for _, path := range old {
			RemoveAll(path) // best effort
		}
	}
	if dirExists {
		if err := RemoveAll(dir); err != nil {
			return "", err
		}
	}

			// and not something that we want to remove. Also, we'd like to preserve
			// the access log for future analysis, even if the cache is cleared.
			subdirs, _ := filepath.Glob(filepath.Join(str.QuoteGlob(dir), "[0-9a-f][0-9a-f]"))
			printedErrors := false
			if len(subdirs) > 0 {
				if err := sh.RemoveAll(subdirs...); err != nil && !printedErrors {
					printedErrors = true
					base.Error(err)
				}
			}

		if _, err := pathpkg.Match(glob, ""); err != nil || !validEmbedPattern(glob) {
			return nil, nil, fmt.Errorf("invalid pattern syntax")
		}

		// Glob to find matches.
		match, err := fsys.Glob(str.QuoteGlob(str.WithFilePathSeparator(pkgdir)) + filepath.FromSlash(glob))
		if err != nil {
			return nil, nil, err
		}

		// Filter list of matches down to the ones that will still exist when