[tex-live] Strange bug with l3kernel

[Joseph Wright]

On 16/05/2018 20:44, Joseph Wright wrote:
> On 16/05/2018 20:13, Benoit Rivet wrote:
>> I recently updated MacTex 2018 with Tex Live Utility and stumbled upon 
>> a strange bug. The following minimal example compiled with lualatex 
>> fails :
>>
>> % !TEX TS-program = luaLaTeX
>> \documentclass{article}
>> \usepackage[utf8]{luainputenc}
>> \usepackage{fouriernc}
>> \usepackage{mdframed}
>>
>> \begin{document}
>>
>> \end{document}
>>
>> Here are the relevant lines in the log :
>>
>>> (/usr/local/texlive/2018/texmf-dist/tex/latex/l3kernel/expl3-code.tex
>>> ! Illegal parameter number in definition of \c__tl_i_ogonek_tl.
>>> <to be read again>
>>> \crcr
>>> l.26054   \__tl_tmp:w \c__tl_i_ogonek_tl  { 012F }
>>> ?
>>> ! Illegal parameter number in definition of \c__tl_I_ogonek_tl.
>>> <to be read again>
>>> \crcr
>>> l.26055   \__tl_tmp:w \c__tl_I_ogonek_tl  { 012E }
>>> ?
>>
>> Everything compiles fine when reverting to the previous versions of 
>> l3experimental, l3kernel et l3package (46875, 46875, 46712 instead of 
>> the current 47705, 47718, 47705) or when removing one of the three 
>> packages used in the example or compiling with pdflatex.
>>
>> So… I can’t figure out what is going on :-(
> 
> I can :)
> 
> The issue arises as "į" is made active (by luainputenc) and given a 
> definition which is not happy inside an \edef. The recent change was on 
> the basis that in LuaTeX/XeTeX all of the chars we need to set up 
> internally are catcode 11/12. I'll adjust to harden up.
> 
> Joseph
> 

Fixed in sources. As a workaround you can use

     \documentclass{article}
     \usepackage[utf8]{luainputenc}
     \usepackage{fouriernc}
     \usepackage{etoolbox}
     \robustify{į}
     \robustify{Į}
     \usepackage{expl3}

pending an update (how urgent is this for you?).

Joseph