Bug in 3.141592653-2.6-0.999995 (TeX Live 2023) with fontspec and tabularray?

[Max Chernoff]

Hi Karl,

On Thu, 2024-04-18 at 16:52 -0600, Karl Berry wrote:
> 
>     When using "harf" mode, the font and glyph processing is completely
>     different
> 
> .. and XeTeX always uses harfbuzz. Can someone who wants to pursue this
> see if the original example reproduces with luatex in harf mode? I
> foolishly did not think of this. If luatex+harf and xetex behave the
> same, it seems to me there is no bug to fix ...

LuaTeX seems to be fine in Harf mode too. I tested it with a Devanagari
font to make sure that the HarfBuzz shaper is actually running, but I
don't think that that matters. The LuaTeX output is 1 or 2 scaled points
wider or narrower than the XeTeX output depending on the font size, so
there does appear to be a rounding difference somewhere.

   \parindent=0pt
   
   \def\showdemo#1{
       \ifdefined\directlua
           \input luaotfload.sty
           \font\1={file:NotoSansDevanagari-Regular.ttf:mode=#1;script=dev2;} at 10pt
           \font\2={file:NotoSansDevanagari-Regular.ttf:mode=#1;script=dev2;} at 10.3pt
           \font\3={file:NotoSansDevanagari-Regular.ttf:mode=#1;script=dev2;} at 11pt
       \else
           \font\1="[NotoSansDevanagari-Regular]" at 10pt
           \font\2="[NotoSansDevanagari-Regular]" at 10.3pt
           \font\3="[NotoSansDevanagari-Regular]" at 11pt
           \def\showdemo##1{}
       \fi
   
       \vfill\eject
       {\bf #1 \par}
       \1 \test{क्रर्कि-क्रर्कि}
       \2 \test{क्रर्कि-क्रर्कि}
       \3 \test{क्रर्कि-क्रर्कि}
   }
   
   \def\test#1{%
       \setbox0=\hbox{#1}
       \dimen0=\dimexpr1em\relax
       \vskip4pt
       \vbox to 26pt{
           \tt
           \leavevmode\llap{Font:  }\number\dimen0 sp~ \the\dimen0\par
           \leavevmode\llap{Width: }\number\wd0    sp  \the\wd0   \par
           \vss
       }
       \vbox to 26pt{\hsize=\wd0 \leftskip 0pt plus 1fil                     #1\vss}
       \vbox to 26pt{\hsize=\wd0 \rightskip0pt plus 1fil                     #1\vss}
       \vbox to 26pt{\hsize=\wd0 \leftskip 0pt plus 1fil \rightskip\leftskip #1\vss}
       \par
   }
   
   \showdemo{harf}
   \showdemo{base}
   \showdemo{node}
   
   \bye


Thanks,
-- Max