Line breaks in log file from unicode-math

Question

I have reported this bug against latexrun. It seems to be incapable of dealing with braces that span over multiple lines. Consider this example:

\documentclass{article}
\usepackage{unicode-math}

\begin{document}
Test
\end{document}

Even with the following settings, latexrun complains about unbalanced braces.

export max_print_line=1000         
export error_line=254
export half_error_line=238

The log contains a line with the following ending (the line break occurs at column 274).

FontAdjustment={\fontdimen
. 8\font =443678.72sp\relax \fontdimen 9\font =258211.84sp\relax \fontdimen

Where does this line break come from? Is there a way to work around it?

Answer 1

The break arises as the code in unicode-math uses the expl3 line-wrapping system to break the lines 'sensibly'. In this case, you have a very long line with no spaces, so the first place after a single token is taken as a break. You can do something like

\documentclass{article}
\usepackage{expl3}
\ExplSyntaxOn
\int_set:Nn \l_iow_line_count_int { 1000 }
\ExplSyntaxOff
\usepackage{unicode-math}

\begin{document}
Test
\end{document}

to tell the wrapping system to use 1000 chars as a width, though this of course will mess up any other pretty-printing.