remove "./" of "\currfileabspath" when using lualatex

Question

I have a small problem with the package currfile and the command \currfileabspath. When compiling the file using (pdf|xe)latex I get the expected result, but if I use lualatex it adds ./ to the absolute path of the file. I'm using TeXLive 2018 (updated) in Fedora 29, the working directory looks like this:

[pablo@fedora forum] $ pwd
/home/pablo/forum
[pablo@fedora forum] $ ls -lha
total 12K
drwxrwxr-x.  2 pablo pablo 4,0K feb 17 13:11 .
drwx------. 43 pablo pablo 4,0K feb 17 13:10 ..
-rw-rw-r--.  1 pablo pablo  187 feb 17 13:03 test.tex

My MWE (test.tex) is this:

\documentclass{article}
\usepackage[abspath]{currfile}
\setlength{\parindent}{0pt} 
\begin{document}
\texttt{\jobname.pdf} created from file \texttt{\currfileabspath}%
\end{document}

I use the following line to compile it:

$ pdflatex -recorder test.tex

with which I obtain:

test.pdf created from file /home/pablo/forum/test.tex

which is correct, but if I change it to:

$ lualatex -recorder test.tex

I get

test.pdf created from file /home/pablo/forum/./test.tex

How can I solve this? regards

Answer 1

Removing the period is easy:

\documentclass{article}
\usepackage[abspath]{currfile}
\usepackage{expl3}
\ExplSyntaxOn
\regex_replace_once:nnN{\.\/}{}\currfileabspath
\ExplSyntaxOff
\setlength{\parindent}{0pt}
\begin{document}
\texttt{\jobname.pdf} created from file 
\currfileabspath%
\end{document}

But imho it would be better if currfile would do this, when lualatex is used, as the period and the slash is also in other commands.

Answer 2

You can easily get the absolute path in LuaTeX using the FFI and a platform-dependent function. On POSIX-based systems you can use the realpath() function, on Windows you would use _fullpath (I think).

Because it uses the FFI you have to enable --shell-escape.

In tex.sprint I use the first argument -2 to switch to verbatim catcodes, in case the path contains any characters which are treated special by TeX, such as {}$%#.

\documentclass{article}
\directlua{

local ffi = assert(require"ffi")
ffi.cdef[[

char *realpath(const char *path, char *resolved_path);

]]

function realpath(path)
    local p = ffi.C.realpath(path, ffi.NULL)
    if p \string~= ffi.NULL then
        return ffi.string(p)
    end
    return nil
end

}

\def\currfileabspath{%
  \directlua{tex.sprint(-2, realpath(status.filename))}%
}

\begin{document}
\currfileabspath
\end{document}