private static String requireNonNormalizable(String segment) {
            return require( ! (segment.isEmpty() || segment.equals(".") || segment.equals("..")),
                           segment, "path segments cannot be \"\", \".\", or \"..\"");
        }
Parses the given raw, normalized path string; this ignores whether the path is absolute or relative.
vespajlib/src/main/java/ai/vespa/http/HttpURL.java