tex4ht ignores \input@path when looking for .4ht files?

Question

My situation is like this. I have a LaTeX file that I want to compile with pdflatex and tex4ht, which includes a package in another directory.

The file bug.tex contains:

\documentclass{article}

\usepackage{etoolbox}
\csdef{input@path}{{subdir/}}
\usepackage{mypackage}

\begin{document}

Test: \aaa.

\end{document}

The file subdir/mypackage.sty contains:

\ProvidesPackage{mypackage}
\newcommand\aaa{AAA}

and the file subdir/mypackage.4ht contains:

\renewcommand\aaa{BBB}

When I compile with pdflatex, I get Test: AAA. in the output. But when I compile with make4ht, I still get Test: AAA. instead of Test: BBB.

(When the package is in the working directory, it works as expected.)

This indicates to me that, when using tex4ht, the redefinition of input@path occurs, but when including packages, tex4ht doesn't search it for .4ht files.

Can anyone help me work around this?

Of course, you are probably thinking that I'm doing this wrong, and I should put the package in my texmf, or set $TEXINPUTS correctly, and you would be right. But I have a complex project that I will need to share with colleagues who I can't expect to use make, so it would be much better if I can manage everything from within the tex files.

Answer 1

tex4ht didn't support the \input@path by default. I've just added the support to the sources, so it should be included in TL soon. It was necessary to change some core macros that are not possible to modify using a .cfg file. So until the update is available, you can use the following workaround:

\InputIfFileExists{mypackage.4ht}{}{}
\Preamble{xhtml}
\begin{document}
\EndPreamble

The \InputIfFileExists command searches the \input@path and includes the required file if it is found.

The result: