lualatex underbrace and bars

[PatrickMassot]

This one is really weird. Consider the following tex file:

\documentclass{article}

\usepackage{amsmath}
\usepackage{unicode-math}

\begin{document}
\[
  f = \underbrace{\bar{h} + k}_{\text{test}}
\]

\[
  f = \underbrace{\overline{h} + k}_{\text{test}}
\]
\end{document}

Compiling with LuaTeX, Version 0.95.0 (TeX Live 2016) gives with a misplaced underbrace when bar is used but not when overline is used. Removing the unicode-math package solves the problem. Compiling the same file with xelatex XeTeX, Version 3.14159265-2.6-0.99996 (TeX Live 2016) solves the problem.

[wspr]

Have you tried with TeX Live 2017? I’m not on an up-to-date computer at present… this is potentially/probably an engine issue, not unicode-math (but I wouldn’t rule out the latter, either).

[eg9]

I can confirm the wrong behavior with TL 2017. I seem to remember having seen something similar in the past.

Found:

https://tex.stackexchange.com/questions/323797/

I applied the workaround and it seems to work.

[PatrickMassot]

@wspr: I don't know exactly what is an engine issue but the example I gave uses no unicode and the issue disappear if I remove the unicode-math package.

[wspr]

"Unicode" in this context refers more to the fonts and the engine. Much of the underlying maths engine is altered when you load the package, which is why you're seeing a problem.

[eg9]

@PatrickMassot The issue appears with LuaLaTeX, but not with XeLaTeX, which is referred to as “engine issue”.