Having two document environments in the same .tex file makes plasTeX throw an error when picking a filename

[christianp]

Someone had an old copy of their document at the end of their .tex file. plasTeX parse this and created a new document node, but couldn't pick a filename for it because the wildcard spec Chirun gives it says to use the title, and the second document's title is empty. plasTeX assumes that every attribute in the spec has at least one item.

Here's a minimal document that reproduces this:

\documentclass{article}

\usepackage{chirun}
\usepackage{amsmath}

\begin{document}

This is my thing!

\end{document}

\begin{document}

This is my thing!

\end{document}