Current best practice re. cross-references to last page

Question

I am/was using pageslts, which I know is not supposed to be compatible with current LaTeX. As far as I understand, there is no alternative offering the same functionality, but I'd like to at least find a way to get a reference to the last page of the document.

I need this to work whether or not hyperref is loaded and whether fancyref or cleveref is used.

I've been playing with putting a label into either enddocument or shipout/lastpage. Of the two, shipout/lastpage seems to work a little better, but I'm not at all convinced by my approach.

There are also \g_shipout_readonly_int/\ReadOnlyShipoutCounter and \g_shipout_totalpages_int/totalpages but those don't, as far as I can tell get me a hyperlink target if hyperref is loaded.

The documentation of the new shipout routine and hooks explains how to replace various packages, but I can't find anything specifically about lastpage or pageslts.

I'm not sure I'm using the correct hook. I'm not sure I should be using a hook at all. I'm really not sure I should be using \phantomsection. I'm not at all sure using pageslts isn't better, even if it isn't really compatible. (For basic usage, it still seems to work and then it figures out where to put its labels.)

\documentclass{book}
\usepackage{kantlipsum}
\AddToHook{begindocument}{\ProvideDocumentCommand \phantomsection {}{}}
\usepackage{bookmark}
\usepackage{cleveref}
\AddToHook {enddocument} {\phantomsection\label{enddocument:lastpage}}
\AddToHook {shipout/lastpage} {\phantomsection\label{shipout-lastpage:lastpage}}
\begin{document}
\frontmatter
The last page of this document is \pageref{enddocument:lastpage}.

The last page of this document is \pageref{shipout-lastpage:lastpage}.

The last page of this document is \cpageref{endocument:lastpage,shipout-lastpage:lastpage}.

\mainmatter
\kant[1-10]

\backmatter
The last page of this document is \thepage.


\end{document}

What's the recommended way to do this now?

Answer 1

There is not really a need to set an anchor as hyperref adds anchors to all pages anyway:

\documentclass{book}
\usepackage{kantlipsum}
\usepackage{bookmark}
\usepackage{cleveref}
\makeatletter
\AddToHook {shipout/lastpage} {\gdef\@currentHref{\@currentHpage}\label{shipout-lastpage:lastpage}}
\makeatother
\begin{document}
\frontmatter

The last page of this document is \pageref{shipout-lastpage:lastpage}.

The last page of this document is \cpageref{shipout-lastpage:lastpage}.

\mainmatter
\kant[1-10]

\backmatter
The last page of this document is \thepage.
\end{document}

This interface requires a current LaTeX and hyperref version. Loading hyperref is not required, if it is not present \@currentHpage is simply empty. There will naturally be no anchor if you load hyperref with pageanchor=false, in this case you should add one manually, e.g. with \MakeLinkTarget, see hyperref-linktarget.pdf.

You can also label and reference the pageanchor with a property, naturally this requires new reference commands:

\documentclass{book}
\usepackage{kantlipsum}
\usepackage{bookmark}
\AddToHook {shipout/lastpage} {\RecordProperties{shipout-lastpage:lastpage}{page,pagetarget}}

\begin{document}
\frontmatter

The last page of this document is \hyperlink{\RefProperty{shipout-lastpage:lastpage}{pagetarget}}{\RefProperty{shipout-lastpage:lastpage}{page}}.


\mainmatter
\kant[1-10]

\backmatter
The last page of this document is \thepage.
\end{document}