Incompatibility between kvoptions and babel

Question

I'm using kvoptions in my document class and it's worked nicely so far, but after a major rewrite I started getting strange errors that I was able to trace back to the babel package.

MWE:

%% myclass.cls

\NeedsTeXFormat{LaTeX2e}[2018/04/01]
\ProvidesClass{myclass}

\RequirePackage[patch]{kvoptions}

\DeclareStringOption{title}
\ProcessKeyvalOptions*

\LoadClass{article}
\title{\myclass@title}
\RequirePackage[english]{babel}

\endinput

\documentclass[title={Here be dragons}]{myclass}

\begin{document}
Lorem Ipsum
\end{document}

An excerpt from the log (paths omitted for brevity):

babel.sty:460: LaTeX Error: Missing \begin{document}. [    {}}]
babel.sty:460: Too many }'s. [    {}}]
babel.sty:475: LaTeX Error: Missing \begin{document}. [    \ifin@\edef\bbl@tempc{\bbl@tempb}\fi}]

Without the kvoptions patch, the errors are getting worse:

babel.sty:339: LaTeX Error: Missing \begin{document}. [\ProcessOptions*]
babel.sty:339: You can't use `macro parameter character #' in horizontal mode. [\ProcessOptions*]
TeX STOPPED: File ended while scanning use of \reserved@{##1,##2\reserved@b }\def \reserved@b ##1,\reserved@b ##2\reserved@b 
TeX reports the error was in file:3 
myclass.cls:13: LaTeX Error: Unknown option `english' for package `babel'. []

Analysis: The problem is that I have used spaces (and braces) in the global option (title) and this option is obviously passed on to babel. Without the spaces, the errors don't occur.

Question: Can I prevent document class options from being used as global options by packages? Or is there some work-around akin to \hypersetup{} for me to use instead of options? I could live with that.

Answer 1

I solved this problem by taking inspiration from an answer to another question. Applied to the MWE above, it would look like this:

%% myclass.cls

\NeedsTeXFormat{LaTeX2e}[2018/04/01]
\ProvidesClass{myclass}

\RequirePackage{kvoptions}

\DeclareStringOption{title}
\ProcessKeyvalOptions*

\LoadClass{article}

\newcommand*{\docsetup}[1]{
  \kvsetkeys{myclass}{#1}
  \title{\myclass@title}
  \RequirePackage[english]{babel}
}

\endinput

\documentclass{myclass}
\docsetup{title={An awesome title}}

\begin{document}
Lorem Ipsum
\end{document}