Thanks! Your fix does a good job at the site of the stacktrace, but it seems easier to just say at the beginning of the function if (input.isEmpty()) { return input; }. That way all the code below that can take as a precondition "this string has length > 0". That's more robust than having to check for it at every point.

Also, update your changelog entry so that it points to this PR.

Thanks for the PR!