xltabular and booktabs failing on "(" -- toprule, midrule, bottomrule only on first column

[Alexander Krumeich]

Herbert,

thanks for the quick response. I tried changing from tabular* to
tabularx, but the problem persists. This is the modified MWE:

\documentclass[a4paper]{article}
\usepackage{xltabular}
\usepackage{booktabs}

\begin{document}
\begin{tabularx}{\textwidth}{@{}ll@{}}
  \toprule
  Column 1 & Column 2 \\
  \midrule
  (None) & Other \\
  \bottomrule
\end{tabularx}
\end{document}

Again: if I remove the opening parenthesis, lualatex (and latex as
well, btw) compiles the MWE. With the opening parenthesis, however, it
crashes. This only occurs when the opening parenthesis is immediately
after either \toprule or \midrule. Subsequent table rows have no
problem.

The second issue of the original message also persists with tabularx:
table rules only extend over the first column of the table.

Thanks again for looking into this!

Alexander



On Tue, Nov 12, 2019 at 6:24 PM Herbert Voss <Herbert.Voss at fu-berlin.de> wrote:
>
> Am 12.11.19 um 14:30 schrieb Alexander Krumeich:
>
> > there are two bugs in the booktabs package, that might have been caused
> > by the October update to booktabs.
> >
> > Consider the following example:
> >
> > \documentclass[a4paper]{article}
> >
> > \usepackage{xltabular}
> > \usepackage{booktabs}
> >
> > \begin{document}
> >
> > \begin{tabular*}{\textwidth}{@{}ll@{}}
> >    \toprule
> >    Column 1 & Column 2 \\
> >    \midrule
> >    (None) & Other \\
> >    \bottomrule
> > \end{tabular*}
> >
> > \end{document}
> >
> > The first bug:
> > LuaLaTeX crashes with this error:
> >
> > ! Undefined control sequence.
> > <argument> ...al \expandafter \let \cmrsideswitch
> >                                                    \@tempa \fi \fi
> > l.13   (None)
>
> Loading package xltabular and using tabular* will not work. Use
> environment xltabular instead or
>
>
> \documentclass[a4paper]{article}
>
> \usepackage{xltabular}
> \usepackage{booktabs}
>
> \begin{document}
>
> \let\xltabular\undefined
> \begin{tabular*}{\textwidth}{@{}ll@{}}\toprule
> Column 1 & Column 2 \\\midrule\relax
> (None) & Other \\\bottomrule
> \end{tabular*}
>
> \end{document}
>
>
> Herbert