\uchyph=0 on XeLaTeX

[aminophen]

Brief outline of the bug

I think \uchyph=0 is not working on XeLaTeX.

• LuaLaTeX, pdfLaTeX, LaTeX: OK
• XeLaTeX: NG

Strangely, plain XeTeX (replace the first 3 lines with \hsize=345pt) seems OK; so I don't think XeTeX engine itself is doing something wrong.

Your minimal example showing the bug

The code is based on https://tex.stackexchange.com/questions/107208 (Joseph's answer).

\RequirePackage{latexbug}
\documentclass{article}
\begin{document}

\uchyph=0 %

\begingroup
  \lccode`C=`C
  Some filler text.
  Some filler text.
  Some filler text.
  Some filler text.
  Capitalised word. % Capi-talised
  \par
\endgroup

\begingroup
  \lccode`C=`c
  Some filler text. 
  Some filler text. 
  Some filler text. 
  Some filler text. 
  Capitalised word. % (no hyphenation)
  \par
\endgroup

\begingroup
  \uccode`C=`C
  Some filler text. 
  Some filler text. 
  Some filler text. 
  Some filler text. 
  Capitalised word. % (no hyphenation)
  \par
\endgroup

\begingroup
  \uccode`C=`c
  Some filler text. 
  Some filler text. 
  Some filler text. 
  Some filler text. 
  Capitalised word. % (no hyphenation)
  \par
\endgroup

\end{document}

Log (and possibly PDF) file

• xelatex-hyphenation.log
• xelatex-hyphenation.pdf

[FrankMittelbach]

looks to me like an engine bug after all (on first glance). It works with plain xetex only because then \tenrm 8bit font is used, while latex uses a unicode font (TU encoded). The moment you force xelatex to use OT1 or T1 via \usepackage[OT1]{fontenc} \fontamily{cmr}\selectfont the result is like with the other engines. So my initial guess is that xetex ignores the uhyph setting somehow with unicode fonts.

[aminophen]

So my initial guess is that xetex ignores the uhyph setting somehow with unicode fonts.

Thanks for the hint: I wrote a patch to fix that: see my gist

• https://gist.github.com/aminophen/44039ae0f78c63cca57781717ce13ec4

I'm glad if someone can test it

[josephwright]

Seems clear this is an engine issue, so 'report elsewhere' for us (not a LaTeX bug).

[FrankMittelbach]

Hironobu

I'm glad if someone can test it

looks like being the right place, but for testing you would need to push that into the direction of the xetex developers, none of us deal with engine work (well I did 25 years ago or so ...)

[aminophen]

I was planning to do that, of course ;-) Done: https://sourceforge.net/p/xetex/bugs/145/