This LaTeX package helps you make your build more fragile, which is good if you care about quality. Every warning it will turn into an error and LaTeX engine will fail with a non-zero error message.

First, install it from CTAN and then use in the preamble:

\documentclass{article}
\usepackage{fail-fast}
\begin{document}
This reference is broken: \ref{foo}
\end{fail-fast}
\end{document}

Otherwise, you can download fail-fast.sty and add to your project.

If you want to contribute yourself, make a fork, then create a branch, then run l3build ctan in the root directory. It should compile everything without errors. If not, submit an issue and wait. Otherwise, make your changes and then run l3build ctan again. If the build is still clean, submit a pull request.

Copyright (c) 2023-2025 Yegor Bugayenko, MIT License