# biblatex broken overnight

As late as last week my setup for biblatex worked fine. Going back to the same project today not even a minimal file compiles:

\documentclass{article}

\usepackage{biblatex}

\begin{document}

test%foo\nocite{*}
%\printbibliography

\end{document}


but breaks off with

/usr/local/texlive/2017/texmf-dist/tex/latex/biblatex/biblatex.sty:3776: LaTeX
Error: Missing \begin{document}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
...

l.3776   australian,newzealand}
?
/usr/local/texlive/2017/texmf-dist/tex/latex/biblatex/biblatex.sty:3776: Math f
ormula deleted: Insufficient symbol fonts.
\expandafter ->american|

l.3776   australian,newzealand}


And keeps repeating the last one until

 (That makes 100 errors; please try again.)


when I ignore it.

Files without biblatex work as expected.

Using tlmgr to go my two backup versions of biblatex back in time to 1st Jan I still get the same errors.

Could this be another update from the last week or so that causes this?

If I swich back to TL 16 things work as expected. (For my work I need TL 17 because of packages.)

• I worked around this issue by reverting back to the previous version of etoolbox. – tucuxi Feb 6 '18 at 22:12

This is due to a (faulty) change in etoolbox, or rather an oversight in a change: see https://github.com/josephwright/etoolbox/issues/19. A temporary fix is to patch around the issue:

\documentclass{article}

\usepackage{etoolbox}
\makeatletter
\long\def\etb@listitem#1#2{%
\expandafter\ifblank\expandafter{\@gobble#2}
{}
{\expandafter\etb@listitem@i
\expandafter{\@secondoftwo#2}{#1}}}
\long\def\etb@listitem@i#1#2{#2{#1}}
\makeatother
\usepackage{biblatex}


An update is on the way to CTAN and will therefore be available within around 48 hours via the usual channels.

• typical tex.SE-problem: cannot accept perfect answer because of time restrictions ;) – Florian Feb 6 '18 at 10:17
• I can confirm that the 2.5c update of etoolbox avaible on my CTAN mirror now solves the problem. – Florian Feb 7 '18 at 8:23
• New version is now in TeXLive! I just updated and problem solved! – tatojo Feb 7 '18 at 14:10
• Same problem occurs on MiKTeX. I did a clean reinstall today and have updated packages, but the problem persists. I presume MiKTeX updates are lagging behind CTAN. Anyway, the workaround is great. Many thanks. – LimnoLeon Feb 8 '18 at 2:26
• @LimnoLeon As of this morning the 7. Feb. update ships etoolbox v2.5c which fixes this issue (apparently there is still another issue github.com/josephwright/etoolbox/issues/20, but that does not affect biblatex). – moewe Feb 8 '18 at 7:25