If the user has configured git with log.showSignature set to true, then gitHeadInfo.gin will also contain the signature information of the latest commit. This will trigger an error during compilation:
(/usr/share/texmf-dist/tex/latex/eso-pic/eso-pic.sty) (./.git/gitHeadInfo.gin
./.git/gitHeadInfo.gin:1: LaTeX Error: Missing \begin{document}.
This problem can be circumvented by also using the flag --no-show-signature when reading the git data via git log.