reference commands are not correctly tagged

[u-fischer]

Reference command have currently two problems regarding tagging:

• without hyperref they are not tagged at all.
• \eqref is tagged as Lbl as it inherits tagging from the label in the equation.

The following resolves both (when hyperref it will replace the references with links, that is ok, but can be adjusted if needed)

\DocumentMetadata{uncompress,testphase={phase-III,math}}
\documentclass{article}
\usepackage{amsmath} 

\ExplSyntaxOn\makeatletter
\def\@kernel@target@exp#1{\cs_if_exist:cT
   {r@#1}{\tl_item:cn{r@#1}{4}}}

\NewSocket{tagsupport/ref/begin}{1}
\NewSocket{tagsupport/ref/end}{0}
\NewSocket{tagsupport/inlineinsert/begin}{1}
\NewSocket{tagsupport/inlineinsert/end}{0}

\NewSocketPlug{tagsupport/ref/begin}{kernel}
 {
  \leavevmode\tagmcend 
  \tagstructbegin{tag=Reference}
  \tag_struct_gput:nne 
   {\g__tag_struct_stack_current_tl}
   {ref_dest}{\@kernel@target@exp{#1}}
  \tagmcbegin{}
 }

\NewSocketPlug{tagsupport/ref/end}{kernel}
 {\tagmcend \tagstructend \tagmcbegin{}}

\AssignSocketPlug{tagsupport/ref/begin}{kernel} 
\AssignSocketPlug{tagsupport/ref/end}{kernel} 

\NewSocketPlug{tagsupport/inlineinsert/begin}{kernel}
  {\tagmcend \tagstructbegin{#1}\tagmcbegin{}}
\NewSocketPlug{tagsupport/inlineinsert/end}{kernel}
  {\tagmcend \tagstructend \tagmcbegin{}}

\AssignSocketPlug{tagsupport/inlineinsert/begin}{kernel} 
\AssignSocketPlug{tagsupport/inlineinsert/end}{kernel} 

\RenewDocumentCommand\ref{sm}
 {
  \UseTaggingSocket{ref/begin}{#2}
  \IfBooleanTF{#1}{\@kernel@sref{#2}}{\@kernel@ref{#2}}
  \UseTaggingSocket{ref/end}
 }

\DeclareRobustCommand{\eqref}[1]
  {
    \textup{%
    \AssignSocketPlug{tagsupport/inlineinsert/begin}{noop}%
    \AssignSocketPlug{tagsupport/inlineinsert/end}{noop}%  
    \tagform@{\ref{#1}}}
  }
\AtBeginDocument
 {
  \@namedef{maketag@@@}#1{%
    \ifmeasuring@
      \hbox{\m@th\normalfont#1}%
    \else
      \UseTaggingSocket{inlineinsert/begin}{tag=Lbl}%      
      \hbox{\m@th\normalfont#1}%
      \UseTaggingSocket{inlineinsert/end}%
    \fi
    } 
  }  
\ExplSyntaxOff\makeatother

\begin{document}

\section{section}\label{sec}

\ref{sec}
 
\begin{align}
x \label{eq}
\end{align}

\eqref{eq}
\end{document}

[teepeemm]

A converse problem: \text{\ref} from within the AMS environments leads to "Object missing in object reference" and "Inconsistent entry found" errors in PAC.

% !TEX program = LuaLaTeX
\DocumentMetadata{lang=en,testphase=latest,uncompress,
  pdfversion=1.7,pdfstandard=ua-1,
}
\documentclass{article}
\usepackage{amsmath}
\usepackage{hyperref}
\title{title}
\begin{document}
\section{Section}\label{sec_label}
\[a+b=c\qquad\text{eq ok from Section \ref{sec_label}}\]
\begin{gather*}
	a+b=c\qquad\text{gather good from Section \ref*{sec_label}}\\
	a+b=c\qquad\text{gather bad from Section \ref{sec_label}}.
\end{gather*}
\begin{multline*}
	a+b=c\qquad\text{multline good from Section \ref*{sec_label}}\\
	a+b=c\qquad\text{multline bad from Section \ref{sec_label}}.
\end{multline*}
\begin{align*}
	a+b&=c\qquad\text{align good from Section \ref*{sec_label}}\\
	a+b&=c\qquad\text{align bad from Section \ref{sec_label}}.
\end{align*}
\end{document}

The \ref* commands are ok, and so is \ref in \[...\]. What I find odd is that all four \ref seem to have the same /K [,/Obj<</A<</D section.1>> >>], which I think would be the object reference in question. (Is it related that show-pdf-tags.lua dies in the gather* because "attempt to index a nil value (field 'Obj')"?)

[u-fischer]

@teepeemm please do not use an existing issue to report a problem only because it looks vagely related. This issue here is about the \ref command without hyperref. Unless you are really sure that you are reporting the same problem better open a new issue.

Your problem (which is real bug) is closely related to hyperref and has nothing to do with the issue at hand. I opened a new issue about this #920