\nameref using 'unexpanded' text?

Question

Suppose I define a custom command \exercise as follows.

\newcounter{exercise}
\newcommand\exercise{%
    \refstepcounter{exercise}%
    \section*{Exercise \theexercise}%
}

Now, in the following example, I want to use \nameref from the hyperref package.

\exercise\label{ex:first}
foo

\exercise\label{ex:second}
see \nameref{ex:first}

\exercise\label{ex:third}
bar

This produces "see Exercise 2" instead of "see Exercise 1". It seems like the 'unexpanded' text is used, expanding into the current counter value. How can I make sure that \nameref{ex:first} produces "Exercise 1"?

(Of course, I could just use Exercise~\ref{ex:first}, but this is more error-prone. And, in the future, I may want to replace "exercise" by "problem" without having to find and replace all occurences in my document.)

---

Full example:

\documentclass{article}

\usepackage{hyperref}

\newcounter{exercise}
\newcommand\exercise{%
    \refstepcounter{exercise}%
    \section*{Exercise \theexercise}%
}

\begin{document}

\exercise\label{ex:first}
foo

\exercise\label{ex:second}
see \nameref{ex:first}

\exercise\label{ex:third}
bar

\end{document}

Answer 1

Indeed, you need to pass the expansion of \theexercise, because hyperref doesn't do it to the title.

\documentclass{article}
\usepackage{hyperref}

\newcounter{exercise}
\newcommand\exercise{%
  \par % just in case
  \refstepcounter{exercise}%
  \begingroup\edef\x{\endgroup
    \noexpand\section*{\unexpanded{Exercise} \theexercise}%
  }\x
}

\begin{document}

\exercise\label{ex:first}
foo

\exercise\label{ex:second}
see \nameref{ex:first}

\exercise\label{ex:third}
bar

\end{document}

This is the (abridged) contents of the .aux file:

\newlabel{ex:first}{{1}{1}{Exercise 1}{section*.1}{}}
\newlabel{ex:second}{{2}{1}{Exercise 2}{section*.2}{}}
\newlabel{ex:third}{{3}{1}{Exercise 3}{section*.3}{}}

It was

\newlabel{ex:first}{{1}{1}{Exercise \theexercise }{section*.1}{}}
\newlabel{ex:second}{{2}{1}{Exercise \theexercise }{section*.2}{}}
\newlabel{ex:third}{{3}{1}{Exercise \theexercise }{section*.3}{}}

with your code.

Note. Why \unexpanded{Exercise}? In the particular case it is obviously unnecessary, but it would be for the German “Übung”.

---

You might use cleveref instead.

\documentclass{article}
\usepackage{hyperref}
\usepackage[nameinlink]{cleveref}

\newcounter{exercise}
\newcommand\exercise{%
  \par % just in case
  \refstepcounter{exercise}%
  \section*{Exercise \theexercise}
}
\crefname{exercise}{Exercise}{Exercises}

\begin{document}

\exercise\label{ex:first}
foo

\exercise\label{ex:second}
see \cref{ex:first}

\exercise\label{ex:third}
bar

\end{document}

The output is the same in both cases.

Can we avoid the \edef\x{\endgroup trick? Yes, of course.

\documentclass{article}
%\usepackage{xparse} % not needed for LaTeX 2020-10-01 or later
\usepackage{hyperref}
\usepackage[nameinlink]{cleveref}

\ExplSyntaxOn
\NewDocumentCommand{\exercise}{}
 {
  \gooz_exercise:ne { \exercisename } { \theexercise }
 }
\cs_new_protected:Nn \gooz_exercise:nn
 {
  \par % just in case
  \refstepcounter{exercise}
  \section*{#1~#2}
 }
\cs_generate_variant:Nn \gooz_exercise:nn { ne }
\ExplSyntaxOff

\newcommand{\exercisename}{Exercise}
\newcounter{exercise}
\crefname{exercise}{\exercisename}{\exercisename s}

\begin{document}

\exercise\label{ex:first}
foo

\exercise\label{ex:second}
see \cref{ex:first} or \nameref{ex:first}

\exercise\label{ex:third}
bar

\end{document}

Note that cleveref is not necessary, just remove the relevant calls if you prefer \nameref.