`cleveref` fails to recognize `\appendix`

[akiyks]

cleveref puts "Chapter" and "section" in references to chapters/sections of after \appendix.
They are expected to be "Appendix" and "appendix".

This is observed against LaTeX2e <2024/11/01> and later.

With LaTeX2e <2023/11/01> installed from Ubuntu 24.04's distro package, I can get the expected behavior.

Minimal example showing the bug

%\RequirePackage{latexbug}       % <-- Commenting out in reporting issues related to cleveref
\documentclass[oneside]{book}

\usepackage{cleveref}

\begin{document}

\mainmatter

\chapter{Intro}
\label{chp:Intro}

\Cref{app:Test} and \cref{app:Test:A} are in appendix.

\appendix

\chapter{Test}
\label{app:Test}

\Cref{chp:Intro} is a chapter.

\section{A}
\label{app:Test:A}

This is under \cref{app:Test}.

\end{document}

Log file (required) and possibly PDF file

MWE.log

MWE.pdf

[u-fischer]

cleveref patches lots of LaTeX commands but sadly hasn't been updated since 8 years and so gets more and more incompatible.

You can try this:

\documentclass[oneside]{book}
 
\usepackage{cleveref}

\AddToHook{cmd/appendix/before}{%
   \crefalias{chapter}{appendix}%
   \crefalias{section}{appendix}%
   \crefalias{subsection}{appendix}%
   \crefalias{subsubsection}{appendix}}
\begin{document}
 
\mainmatter
 
\chapter{Intro}
\label{chp:Intro}
 
\Cref{app:Test} and \cref{app:Test:A} are in appendix.
 
\appendix
 
\chapter{Test}
\label{app:Test}
 
\Cref{chp:Intro} is a chapter.
 
\section{A}
\label{app:Test:A}
 
This is under \cref{app:Test}.
 
\end{document}

[FrankMittelbach]

Since this package is not maintained by us, we can't do much other than suggesting a workaround as done by Ulrike. This really needs fixing at the package end, which is why we require the latexbug line you commented out. It is sad that the package right now is missing an active maintainer so I understand you tried to report here, but we don't have the bandwidth to adopt all kind of packages that got orphaned.

[muzimuzhi]

Could the patches to be added to the existing cleveref firstaid?

[FrankMittelbach]

It could in theory, but this isn't sustainable. We simply don't have the bandwidth to adopt each and every package that has no maintainer any more, so the best solution is that somebody steps up and starts maintaining it. LPPL has provisions to do that if a maintainer drops out.

[josephwright]

Could the patches to be added to the existing cleveref firstaid?

firstaid is for 'temporary' stuff (where we expect the maintainer to take action) or where it's absolutely essential to fix a third-party package - cleverref is 'useful' but not 'vital' in that sense.

[u-fischer]

Well we do already have a number of cleveref patches in firstaid. But the patch in cleveref is actually more complicated as my work-around implies (it has to check if chapter is actually defined, and does also something with subappendix where I have no idea where it comes from). Analyzing all this for a correct firstaid working with all classes costs lots of time which, as Frank wrote, we do not really have.