Hyperref doesn't highlight cites

Question

When I load hyperref inside my own class definition wrapped in AtEndDocument from the etoolbox package, my cites aren't colored. But all used section references get colored.

I could figure out that all cite will be colored when hyperref is loaded directly.

\begin{filecontents}{testclass.cls}
    \ProvidesClass{testclass}[2018-02-27 v0.1 Test class]
    \RequirePackage{etoolbox}
    \LoadClass{scrartcl}

    \RequirePackage[%
     backend = biber
    ]{biblatex}
    \addbibresource{biblatex-examples.bib}

    % Working for ref
    % But not for cite
    \AtEndPreamble{%
        \RequirePackage{hyperref}
        \hypersetup{colorlinks}
    }

    \AtEndDocument{%
        \printbibliography[heading=bibintoc]
    }%

    \endinput
\end{filecontents}

\documentclass{testclass}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

% Working both for ref and cite
%\usepackage{hyperref}
%\hypersetup{colorlinks}

\begin{document}
    \section{Hello world}\label{sec:hello}
        Hello world \cite{doody}
    \section{What ever}
        If've no idea~\ref{sec:hello}
\end{document}

My question is now how can I color cite when hyperref is loaded inside my custom class? Thanks for any advice.

Answer 1

You have a 'race condition' in \AtEndPreamble. biblatex does its hyperref set-up in \AtEndPreamble, and you load hyperref only in \AtEndPreamble. Since your \AtEndPreamble comes in later than biblatex's \AtEndPreamble code, hyperref is not loaded when biblatex does its setup.

One solution is to move your \AtEndPreamble to before you load biblatex

\ProvidesClass{testclass}[2018-02-27 v0.1 Test class]
\RequirePackage{etoolbox}
\LoadClass{scrartcl}

% Working for ref
% But not for cite
\AtEndPreamble{%
    \RequirePackage{hyperref}
    \hypersetup{colorlinks}
}

\RequirePackage[%
 backend = biber
]{biblatex}
\addbibresource{biblatex-examples.bib}

\AtEndDocument{%
    \printbibliography[heading=bibintoc]
}%

\endinput

This is similar to https://github.com/plk/biblatex/issues/585. If you must have the \AtEndPreamble loading hyperref after loading biblatex, you can use hyperref=manual, but you will have to issue \BiblatexManualHyperrefOn after you've loaded hyperref manually yourself.

Answer 2

Well at least I'm not alone. See this discussion here https://github.com/plk/biblatex/issues/585.

You can use the commands mentioned in the discussion:

\begin{filecontents}{testclass.cls}
    \ProvidesClass{testclass}[2018-02-27 v0.1 Test class]
    \RequirePackage{etoolbox}
    \LoadClass{scrartcl}

    \RequirePackage[%
     backend = biber,
     hyperref=manual
    ]{biblatex}

    \addbibresource{biblatex-examples.bib}

    % Working for ref
    % But not for cite
    \AtEndPreamble{%
        \RequirePackage{hyperref}
        \BiblatexManualHyperrefOn
        \hypersetup{colorlinks}
    }

    \AtEndDocument{%
        \printbibliography[heading=bibintoc]
    }%

    \endinput
\end{filecontents}

\documentclass{testclass}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

% Working both for ref and cite
%\usepackage{hyperref}
%\hypersetup{colorlinks}

\begin{document}
    \section{Hello world}\label{sec:hello}
        Hello world \cite{doody}
    \section{What ever}
        If've no idea~\ref{sec:hello}
\end{document}