EDIT: The problem turned out to be with xeCJK. An update has been released (3.3.2 -> 3.3.3). It hasn't shown up yet in TeXlive, however, I have installed it into my local texmf folder and it works.

I have a script that runs tlmgr update --self --all every day, and I woke up yesterday to find that several of my documents won't typeset properly anymore.

I'm using the Tufte-LaTeX layout. Basically I took the sample-book.tex file, removed the sample stuff, and then started writing my document.

I tracked the problem down to the xetex update.

I'm using XeLaTeX to typeset because I need CJK support. So, I'm calling the package xeCJK. There was no update to that recently.

In order to get it to typeset using XeLaTeX, I added the following code to the preamble:

\ifxetex
\newcommand{\textls}[2][5]{%
\begingroup\addfontfeatures{LetterSpace=#1}#2\endgroup
}
\renewcommand{\allcapsspacing}[1]{\textls[15]{#1}}
\renewcommand{\smallcapsspacing}[1]{\textls[10]{#1}}
\renewcommand{\allcaps}[1]{\textls[15]{\MakeTextUppercase{#1}}}
\renewcommand{\smallcaps}[1]{\smallcapsspacing{\scshape\MakeTextLowercase{#1}}}
\renewcommand{\textsc}[1]{\smallcapsspacing{\textsmallcaps{#1}}}
\fi

The error I get when trying to typeset is always the same kind:

! Extra }, or forgotten \endgroup.
<argument> \xeCJK_class_group_end:
                               \CJKecglue
l.527 ...idenote}[\docopt{number}][\docopt{offset}
                                              ]\{\docarg{Sidenote text.}\}

All of these errors are with xeCJK, but I can't figure out how to fix them.

Does anyone have any information or suggestions?

Thanks in advance.