[lltx] microtype's \textls command broken in current TeX Live

[Robert]

On 11.02.17 00:33, Reinhard Kotucha wrote:
> Hi Robert,
> thanks for the amazingly fast response.  But with
>
> ------------------------------------------------------------------
> \documentclass{article}
> \usepackage{fontspec} \setmainfont{TeX Gyre Pagella}
> \usepackage{microtype}
>
> \makeatletter
> \def\MT at ls@fontspec at colon#1:#2:#3:#4\@nil{%
>    \ifx\\#3\\#1:#2\else#1:#2:#3\fi}
> \def\MT at ls@fontspec at font#1 #2\@nil{%
>    "\MT at ls@fontspec at colon#1:::\relax\@nil
>      kernfactor=\MT at minus \ifnum\MT at letterspace@=1000 1\else 0.%
>           \ifnum\MT at minus\MT at letterspace@<100 0\fi
>           \ifnum\MT at minus\MT at letterspace@<10  0\fi
>          \number\MT at minus\MT at letterspace@ \fi;"
>    \ifx\\#2\\ at \f at size pt\else#2\fi\relax
> }
> \makeatother
>
> \usepackage{unicode-math} \setmathfont{texgyrepagella-math.otf}
>
> \begin{document}
> \textls[30]{$x$}
> \end{document}
>
> % Local Variables:
> %  TeX-engine: luatex
> % End:
> ------------------------------------------------------------------
>
> lualatex still complains:
>
> ------------------------------------------------------------------
> (/xopt/texlive/2016/texmf-dist/tex/latex/microtype/mt-msb.cfg)...xmf-dist/tex/l
> uatex/luaotfload/fontloader-basics-gen.lua:113: bad argument #2 to 'find_file'
> (invalid option 'otfkernfactor=0').
> <to be read again>
> relax
> l.28 \textls[30]{$^2$}
> ------------------------------------------------------------------
>
> luaotfload and unicode-math are the only packages which were updated
> recently and everything still worked like a charm a few weeks ago.

Hm, works for me (also on TL16). Can you send me the log file?
(btw, the error message doesn't match with the example ("{$x$}" vs. 
"{$^2$}"))

Best,
-- 
  Robert