Since filecontents is usable into document (LaTeX2e <2019-10-01> patch level 3), the etex package breaks the filecontents new \write...
With TeXLive 2018, the following code is ok:
\documentclass{article}
\usepackage{etex}
\usepackage{filecontents}
\begin{filecontents*}{\jobname-0.vrb}
content
\end{filecontents*}
\begin{document}
A
\end{document}
With TeXLive 2019 and LaTeX2e <2019-10-01>, the following (equivalent) code is broken:
\documentclass{article}
\usepackage{etex}
%\usepackage{filecontents}
\begin{filecontents*}[force]{\jobname-0.vrb}
content
\end{filecontents*}
\begin{document}
A
\end{document}
The error message is:
! No room for a new \write .
\ch@ck ...\else \errmessage {No room for a new #3}
\fi
l.4 \begin{filecontents*}[force]{\jobname-0.vrb}
etex. Is there a particular reason for using it nowadays? – campa Dec 16 '19 at 10:23etexand thefilecontentspackage (which overwrites files by default). With the new version of LaTeX, the default behavior offilecontentsis reversed and, if I add the[overwrite]option, is not compatible withetex... These documents have been working fine for at least 10 years. – Paul Gaborit Dec 16 '19 at 16:12\globcountfail. As I say we can tweak things to avoid this error in your case but full compatibility is hard and keeping the old allocator so not allowing more than 256 count registers by default, when there are 32 thousand available can't really be justified, so something had to give. – David Carlisle Dec 16 '19 at 16:23