Since today (or yesterday) one of my packages [paresse.sty] is giving an error.
I've tracked down the origin to skeyval which says
~/texlive/2020/texmf-dist/tex/latex/skeyval/skeyval-core.tex:8460:
Package skeyval Error: Patching '\end' failed! (skeyval)
'\skvAtEndEnvironment' will not work
I've got the impression that skeyval tries to do some almost legal moves there and that a recent change in the LaTeX2e kernel has put some hindrance in its expectations.
As far as I understand what I read, it seems to me that firstaid.sty could come at the rescue for a quick fix (until I rewrite my style file without skeyval), but I am at my wit's end there.
Any help for a quick fix will be highly appreciated.
skeyvalis tricky to fix, even infirstaid; you'd have to revert to the previous definition of\begin,\end, and\document(it seems) to satisfyskeyval, load the package, then apply the correct patches manually later... I'd say it's easier to just pick another keyval package... – Phelype Oleinik Oct 03 '20 at 09:20ifluatexandifxetexto theiftexpackage. For your toggles you could switch toetoolboxes toggles (so that you could replace the\iftogonwith\iftoggleand\iftogoffwith\nottoggleby search&replace), and setup your complementary keys withxkeyvaldirectly (with\settoggleor\toggletrueand\togglefalse). The changes necessary should be minimal this way. – Skillmon Oct 03 '20 at 10:15