! Missing } inserted

I'm writing a report in latex for school for several months and everything was fine. But recently out of nowhere it stopped compiling and give a lot errors like the following one:

! Missing } inserted.
<inserted text>
}
l.30 \begin{document}


I tried reinstalling the latex distrib but it's still failing.

Even by trying to compile a document without much inside it leads to the same error:

\documentclass[noposter,final]{polytech/polytech}

\schooldepartment{di}
\typereport{prddi5}
\reportyear{2018-2019}

\title{Title}
%\subtitle{}

\student{AAA}{BBB}{AAA.BBB@etu.univ-tours.fr}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\resume{RE}
\motcle{MC}

\abstract{AB}
\keyword{KW}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}
TEST
\end{document}


Seeing that this fails I suspect that it comes from the class polytech/polytech that we have to use (which sources are available here: https://gitlab.com/MrCraftCod/polytechlatex).

Now the thing is that I didn't modify these since the time it was working and now. Plus if I use overleaf with it it does work. So it must come from a package that have been updated and somehow messes up things.

Is there a way for me to narrow down the source of the problem?

• Hi, welcome on LaTeX.SE! Thanks for posting an example. Have you tried making it even more minimal to track down the issue? (E.g., removing \addbibresource, \resume, etc.) – ebosi Jan 25 at 11:49
• This class definitely loads too much packages... It takes awfully long to compile this until the error occurs. – user31729 Jan 25 at 11:57
• If I remove the bib file the same errors happens. Though I can't really remove the resume etc else the class will blow up to my face. – MrCraftCod Jan 25 at 11:58
• @ChristianHupfer I do agree, a lot of things are not used. Though we don't really have a choice. – MrCraftCod Jan 25 at 11:58
• Just looking at the GIT repository contents, somebody changed the main class file and two other style files 4 weeks ago. I guess they screwed something up then. Try contacting the author, or find out how to revert to the previous version. – alephzero Jan 25 at 11:59

Your example document works if you revert array, longtable and tabu to their texlive 2017 versions (just placing old copies of the packages in the same directory as the document).