"! Undefined control sequence. <argument> \fail" after update. But what package?

[Denis Bitouzé]

Le 06/01/22 à 14h27, Alexander Krumeich a écrit :

> Hi there,

Hi,

> today I've updated my TeX Live 2021 distribution for the first time in
> a couple of months. Of course, that update was massive- Afterwards, my
> document stopped working. This is the error in the console, printed
> while processing the preamble:
>
> ---
> (/usr/local/texlive/2021-broken-update/texmf-dist/tex/latex/xpatch/xpatch.sty)
> ! Undefined control sequence.
> <argument> \fail
>
> l.112   {}{\fail}
>
> ?
> ! Undefined control sequence.
> <argument> \fail
>
> l.116   {}{\fail}
>
> ?
> )
> ---
>
> I'm sorry I can't provide an MWE here. Never the less: Is there
> someone here who can point me towards a solution, or at least to
> a better understanding of what's going on here? Thanks.

Maybe this may be useful in order to find the culprit (`rg` stands for
`ripgrep`):

  ┌────
  │ $ rg -F "{\fail}" /usr/local/texlive/2021/texmf-dist/tex/
  │ /usr/local/texlive/2021/texmf-dist/tex/latex/pdfmanagement-testphase/xcolor-patches-tmp-ltx.sty
  │ 52:%\pretocmd{\XC at col@rlet}   {\@expl at color@set@@ne{#2}{#4}}{}{\fail}
  │ 79:%\pretocmd{\XC at definec@lor}{\@expl at color@set@@nnn{#2}{#4}{#5}}{}{\fail}
  │ 
  │ /usr/local/texlive/2021/texmf-dist/tex/latex/tagpdf/tagpdfdocu-patches.sty
  │ 33: {}{\fail}
  │ 52: {}{\fail}
  │ 207:\xpatchcmd\enit at preset{\@firstofone}{\tag at enit@format at preset}{}{\fail}
  │ 209:\xpatchcmd\@item{\box\@labels}{\tagmcend \box\@labels \tagmcbegin{tag=P}}{}{\fail}
  └────

Best.
-- 
Denis