Horizontal rule in latex output no longer works with recent texlive

[marek-step]

Is there a change with horizontal lines? After Homebrew update my markdown file is not compiling with pandoc anymore. I have this error now related to horizontal lines:

`
Error producing PDF.
! Missing number, treated as zero.

\protect
l.153 ...nter}\rule{0.5\linewidth}{\linethickness}

make: *** [typeset] Error 43
`

And I am wondering, whether pandoc is not replacing these lines with the definition of \HRline defined in the template.

What I did so far to resolve this issue: I changed all horizontal lines in file.md
3 Hyphens 3 Underscores 3 Asterix
to:
\HRule
Surrounded by empty lines. And the definition of it in the Headers of my template.tex to:
\newcommand{\HRule}{\begin{center}\rule{0.5\linewidth}{0.2mm}\end{center}}

Working now!

My Platform: Mac Mojave,
Homebrew 2.1.12
Homebrew/homebrew-core (git revision 5b995; last commit 2019-10-05)
Homebrew/homebrew-cask (git revision a8417a; last commit 2019-10-05)
pandoc 2.7.3
Compiled with pandoc-types 1.17.5.4, texmath 0.11.2.2, skylighting 0.8.1
Default user data directory: /Users/mstep/.local/share/pandoc or /Users/mstep/.pandoc

[alerque]

Given that the LaTeX code you are generating is exactly what pandoc is generating, I'm not sure what could be going on here:

$ pandoc -t latex <<< "***"
\begin{center}\rule{0.5\linewidth}{\linethickness}\end{center}

Have you customized your template or included something else that would have messed with the LaTeX definition for \rule perhaps?

[marek-step]

Thank you alerque for this speedy reply. Unfortunately I can't tell, whether it's the update of pandoc (with homebrew) or the update of my LaTeX, which broke things; I made both updates one after the other. After these updates, I got error messages, from pandoc and pdflatex in my vim saying:

LaTeX Warning: Command \InputIfFileExists has changed. 27 Check if current package is valid.

So I suppose there is something wrong with my texlive install. I will dig into it, or wait for the next update of texlive.

Thank you for the pandoc -t latex <<< "***" command! Did not know that! Really impressing!

Thx again

[alerque]

Have you tried boiling this down to a minimum example? Get out of your problem document, leave that folder, go work in a blank space from scratch and try something simple like

$ pandoc -o hr.pdf <<< "***"

Does hr.pdf get built with a horizontal line? If not is the error the same or different? If so, start a test file and start adding features of your failing document until it fails (or start stripping things from your failing one until it works).

[marek-step]

Wow! Did not know this command either! Here the result of it:

pandoc -o hr.pdf <<< "***"
Error producing PDF.
! Missing number, treated as zero.
<to be read again>
\protect
l.51 ...enter}\rule{0.5\linewidth}{\linethickness}

No PDF is produced ...
Which line 51 is meant? Thx again!

[alerque]

LaTeX error messages tend to be a bit cryptic, but I'm guessing that's going to be line 51 of the standalone TeX file created by Pandoc as an intermediary to generating the PDF. Speaking of which if you can post the output of that I'll check to see if it's different than mine:

$ pandoc -s -o test.tex <<< "***"

Attach that file here or post it to a pastbin of some kind. If you happen to have Netcat installed you cat try this:

$ pandoc -s -t latex <<< "***" | nc termbin.com 9999

That will post the generated LaTeX directly and give you a URL back you can copy here.

(Note the <<< syntax is just bash syntactical sugar for echo "***" | pandoc ..., it just feeds a string into STDIN, nothing too magic.)

[marek-step]

I am learning a lot with this thread! I am very grateful for your input ... I just installed netcat and the resulting URL is:

https://termbin.com/0g5r
The output of the TeX-File seams to work:

% Options for packages loaded elsewhere
\PassOptionsToPackage{unicode}{hyperref}
\PassOptionsToPackage{hyphens}{url}
%
\documentclass[
]{article}
\usepackage{lmodern}
\usepackage{amssymb,amsmath}
\usepackage{ifxetex,ifluatex}
\ifnum 0\ifxetex 1\fi\ifluatex 1\fi=0 % if pdftex
  \usepackage[T1]{fontenc}
  \usepackage[utf8]{inputenc}
  \usepackage{textcomp} % provide euro and other symbols
\else % if luatex or xetex
  \usepackage{unicode-math}
  \defaultfontfeatures{Scale=MatchLowercase}
  \defaultfontfeatures[\rmfamily]{Ligatures=TeX,Scale=1}
\fi
% Use upquote if available, for straight quotes in verbatim environments
\IfFileExists{upquote.sty}{\usepackage{upquote}}{}
\IfFileExists{microtype.sty}{% use microtype if available
  \usepackage[]{microtype}
  \UseMicrotypeSet[protrusion]{basicmath} % disable protrusion for tt fonts
}{}
\makeatletter
\@ifundefined{KOMAClassName}{% if non-KOMA class
  \IfFileExists{parskip.sty}{%
    \usepackage{parskip}
  }{% else
    \setlength{\parindent}{0pt}
    \setlength{\parskip}{6pt plus 2pt minus 1pt}}
}{% if KOMA class
  \KOMAoptions{parskip=half}}
\makeatother
\usepackage{xcolor}
\IfFileExists{xurl.sty}{\usepackage{xurl}}{} % add URL line breaks if available
\IfFileExists{bookmark.sty}{\usepackage{bookmark}}{\usepackage{hyperref}}
\hypersetup{
  hidelinks,
  pdfcreator={LaTeX via pandoc}}
\urlstyle{same} % disable monospaced font for URLs
\setlength{\emergencystretch}{3em} % prevent overfull lines
\providecommand{\tightlist}{%
  \setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}
\setcounter{secnumdepth}{-\maxdimen} % remove section numbering

\date{}

\begin{document}

\begin{center}\rule{0.5\linewidth}{\linethickness}\end{center}

\end{document}

Best greetings from Munich - Everybody is digesting the bear from Oktoberfest, except me!

[alerque]

I just compared your dump with mine and they are bit for bit identical. This suggests that it was something that got buggered up in your LaTeX installation rather than with Pandoc.

I'm curious if you can run xelatex text.tex on that standalone tex file created above. Does that give you any flack? Any more useful error output?

[marek-step]

I am always compiling with pdflatex. The test with xelatex and pdflatex are spitting out an empty pdf
The errors are similar (I include a hyperref warning):

Package hyperref Warning: Rerun to get /PageLabels entry.

! Missing number, treated as zero.
<to be read again>
                   \protect
l.51 ...enter}\rule{0.5\linewidth}{\linethickness}
                                                  \end{center}
?
! Illegal unit of measure (pt inserted).
<to be read again>
                   \protect
l.51 ...enter}\rule{0.5\linewidth}{\linethickness}
                                                  \end{center}

With pdflatex I get:

! Missing number, treated as zero.
<to be read again>
                   \protect
l.51 ...enter}\rule{0.5\linewidth}{\linethickness}
                                                  \end{center}
?
! Illegal unit of measure (pt inserted).
<to be read again>
                   \protect
l.51 ...enter}\rule{0.5\linewidth}{\linethickness}
                                                  \end{center}
?

You are certainly right. There is something wrong after the last update of texlive ...

marek

[alerque]

The problem is unlikely to be something in texlive itself, I'm guessing something is borked about the Homebrew packaging or, even more likely, your specific system. I would try a force re-install or uninstall/install of the entire texlive ball of wax — whatever it gives you the option for. I'm sorry it's been a while since I was hands on with brew so I can't remember exactly what you're options are, but support channels or filing an issue with Homebrew is probably your next recourse. Given the evidence so far I'm pretty confident there is not an issue with Pandoc to be resolved here.

[marek-step]

Thx again alerque

I can live with horizontal lines \HRule and definition of it in the tex.template headers: \newcommand{\HRule}{\begin{center}\rule{0.5\linewidth}{0.2mm}\end{center}}

pandoc is incredibly smart and I am big fan of my combo: markdown -> Makefile (JSON) -> LaTeX -> PDF

I am writing Books with it, many many pages ...

Best greetings

marek

[bogdanni]

This issue occurs with the current up-to-date version of TexLive.

[marek-step]

Thx bogdanni
So we have to be patient and wait some updates of texlive ...

Best greetings

[alerque]

@jgm We should probably re-open this and look into what's coming down the pike from LaTeX.

[wilx]

I have hit this too just today but I did not realize it was Pandoc's fault. See TeX, LaTeX and Friends | chat.stackexchange.com chat transcript. It previously only worked accidentally. The solution is to use \@wholewidth as the 2nd argument of the \rule.

[jgm]

I guess I didn't understand the issue (maybe I still don't). What has changed, exactly, in recent LaTeX? What should be changed in pandoc?

[jgm]

I can reproduce the problem now, having updated texlive.

[cbrnr]

Thanks @jgm for fixing this. I'm using horizontal rules in many RMarkdown and Jupyter notebooks, which at the moment can't be converted to PDF. Is the 2.8 release planned to be released anytime soon?

[jgm]

There are still some features we're waiting on for a 2.8 release. I'd say within a month.
In the mean time you can use a nightly if you need to, or refrain from updating texlive.

I'd be curious to get feedback on this question from everyone: would it be better to define \HRule in the default template and use it, rather than hard-coding? Advantages: customization, easier to read. Disadvantage: the LaTeX won't work without the macro defined in the template, so it's not as good for fragments.

[cbrnr]

Thanks, this sounds good. I'm definitely +1 to keep it hard-coded because I prefer if things just work. Unless you can define a default value, but I guess that's not possible.

[aourednik]

I can reproduce the bug with pandoc 2.7.3 In my case the engine is LuaLatex 1.10.0, TeXLive 2019. My template file is the one provided by the rmarkdown package of RStudio.

pandoc -o my.pdf --pdf-engine=lualatex --template=latextemplate05.tex temp.html

yields

Error producing PDF.
! Missing number, treated as zero...

Having a look at the intermediary tex file:

pandoc -o my.tex --pdf-engine=lualatex --template=latextemplate05.tex temp.html

I can find this faulty line in my.tex

\begin{center}\rule{0.5\linewidth}{\linethickness}\end{center}

@marek-step 's workaround put me on the right track, though I could not apply it as such to my case (I am not converting md -> tex -> pdf but html -> tex -> pdf, thus inserting \HRule in the md file was not an option)

Anyway, this is announced to be fixed in pandoc 2.8. For the time being, I've got an easier workaround. Add this line to the latextemplate.tex file:

\renewcommand{\linethickness}{0.05em}

Set the linethicknness to whatever you want. Works for me (can others confirm?).

[vladimiroff]

@jgm have you considered backporting this fix to a 2.7.x release?

[mb21]

We generally don't do that. However, you can use the nightly builds...

[jgm]

I hope to have 2.8 out in the next couple weeks