Babel+french: incompatible with cref and colon in name

Question

If I use colons in \cref{sec:mysection} then it fails to compile when I use the french babel. I can remove the colons in the section names, but this feel a bit dirty. Any other option?

MWE:

\documentclass[]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc} %% For UTF8 chars (accented letters).
\usepackage[french]{babel}
\usepackage[colorlinks]{hyperref}
\usepackage[capitalise,noabbrev]{cleveref}

\begin{document}
The section is \cref{sec:mysection}.

\section{My section}\label{sec:mysection}

\end{document}

Related: prettyref bug when used with babel-french

Answer 1

cleveref uses \edef on the label name, and this doesn't like the active colon. You can try to make it protected (but it would be imho nicer if the babel definitions were protected by default):

\documentclass[]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc} %% For UTF8 chars (accented letters).
\usepackage[english,french]{babel}
\usepackage[colorlinks]{hyperref}
\usepackage[capitalise,noabbrev]{cleveref}

\begin{document}
% after begin document:
\addto\extrasfrench{\protected\edef:{\unexpanded\expandafter{:}}}
\selectlanguage{french}

The section is \cref{sec:mysection}.

\section{My section}\label{sec:mysection}

text: text

\selectlanguage{french}

The section is \cref{sec:mysection}. 

\selectlanguage{english}

The section is \cref{sec:mysection}. 
\end{document}

An alternative is to make the colon safe locally, but it would change typesetting if it done for the whole command so one have to guess a place where to switch that off again (and perhaps there are other commands which still break ...):

\documentclass[]{article}
\usepackage[T1]{fontenc}
\usepackage[english,french]{babel}
\usepackage[colorlinks]{hyperref}
\usepackage[capitalise,noabbrev]{cleveref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@cref{\begingroup}{\begingroup\@safe@activestrue}{}{\fail}
% it is only a guess that the following a good place to reactivate the active chars ...
\patchcmd\@cref{\cref@isstackfull{\@refsubstack}}{\cref@isstackfull{\@refsubstack}\@safe@activesfalse}{}{\fail}
\makeatother
\begin{document}
The section is \cref{sec:mysection} 

\section{My section}\label{sec:mysection}

text: text

\end{document}