I noticed a weird bug when using letterspacing in Harf mode in Luatex
1.15.0 (the TL2022 release); this is not present in 1.13.2 from TL2021.
A minimal example:
\documentclass{article}
\font\base = lmroman10-regular:mode=base,letterspace=100.0
\font\node = lmroman10-regular:mode=node,letterspace=100.0
\font\harf = lmroman10-regular:mode=harf,letterspace=100.0
\font\harfnokern = lmroman10-regular:mode=harf,letterspace=100.0,-kern
\begin{document}
{\base CRITIQUE \quad RITIQ}\par
{\node CRITIQUE \quad RITIQ}\par
{\harf CRITIQUE \quad RITIQ}\par
{\harfnokern CRITIQUE \quad RITIQ}\par
\end{document}
The third RITIQ isn't letterspaced, while everything else is. Note that
RITIQ is the shortest string that shows this behaviour (at least with
this font); shorter substrings do get letterspaced correctly. Curiously
the word CRITIQUE also typesets fine, even though it contains RITIQ as a
substring. Finally, letterspacing also works when kerning is disabled,
even though as far as I can tell none of the letter pairs in RITIQ is
actually kerned in this font.
The bug is not a big deal for me (noticed it when playing with a new
font), so please don't waste lots of time on it.
Marc
