[tex-live] [XeTeX] TeTeX in TeX Live 2015 broken on Mac

[Bruno Le Floch]

On 4/24/15, Khaled Hosny <khaledhosny at eglug.org> wrote:
> On Fri, Apr 24, 2015 at 11:55:41AM +0100, Philip Taylor wrote:
>> Will Robertson wrote:
>> >> On 24 Apr 2015, at 1:51 am, Khaled Hosny <khaledhosny at eglug.org> wrote:
>> >>
>> >> Even shorter:
>> >> \ifnum\XeTeXcountvariations\font>0\fi\bye
>> >
>> > :)
>> > Phew! Glad to hear that (for once) it’s not fontspec that is broken!
>>
>> Well, I have now worked through my entire collection of.ttc fonts, and
>> cannot find one that returns > 0 for \XeTeXcountvariations.  Can anyone
>> let me have a copy of such a font (installable under Windows, of course)
>> so that I can experience at first hand the problem(s) that such fonts
>> can cause ?
>
> Font variations is a feature of Apple’s AAT[1], and there is actually only
> a single publicly available font which has them[2] AFAIK. Anyway, XeTeX
> in TL 2015 dropped support for font variation entirely as xdvipdfmx does
> not support them, so \XeTeXcountvariations always returns 0 now.
>
> Regards,
> Khaled
>
> 1. https://en.wikipedia.org/wiki/Apple_Advanced_Typography
> 2. https://en.wikipedia.org/wiki/Skia_(typeface)

I cannot say anything about fonts, but the code

   \ifnum\XeTeXcountvariations\font>0\fi\bye

gets the syntax of conditionals wrong, as the \fi ends the conditional
before \bye, so \bye is run in all cases.  The correct approach is

   \ifnum\XeTeXcountvariations\font>0 \expandafter\bye\fi

or something similar.

Regards,
Bruno