\hyperbaseurl doesn't work correctly

[u-fischer]

One would expect to be able to change the baseurl locally with it. But this doesn't work.

\documentclass[12pt,a4paper]{article}
\usepackage{l3pdf}
\ExplSyntaxOn
\pdf_uncompress:
\ExplSyntaxOff
\usepackage[
  bookmarks,
  colorlinks,
  unicode,
  baseurl={https://www.latex-project.org},
]{hyperref}


\begin{document}
%\hyperbaseurl{https://www.latex-project.org}
\href{publications.html}{Publications of the \LaTeX3 Project Team}

\url{publications.html}

\href{run:test-utf8.log}{run something}

\hyperbaseurl{https://www.latex3.de/}
\href{help/books.html}  {Books about \LaTeX}

\url{publications.html}

\href{run:test-utf8.log}{run something}

\end{document}

[u-fischer]

Possible fix for file:

\makeatletter
\def\@hyper@linkfile file:#1\\#2#3#4{%
     %file url,link string, name, original uri
  \filename@parse{#1}%
  \ifx\filename@ext\relax
    \edef\filename@ext{\XR@ext}%
  \fi
  \def\use@file{\filename@area\filename@base.\filename@ext}%
  \Hy@IfStringEndsWith\filename@ext\XR@ext{%
    \hyper@linkfile{#2}{\use@file}{#3}%
  }{%
    \ifx\@baseurl\@empty
      \hyper@linkurl{#2}{%
        #4\ifx\\#3\\\else\hyper@hash#3\fi
      }%
    \else
      \hyper@linkurl{#2}{\@baseurl\use@file\ifx\\#3\\\else\hyper@hash#3\fi}%
    \fi
  }%
}

But probably changing \@hyper@readexternallink is better.