Fontspec with lualatex cannot find the italic, bold and bold-italic versions of the XITS font

[callegar]

Description

Using LuaTex and a document relying on the XITS font, as in

 \setmainfont{XITS}

fontspec seems unable to find the italic, bold and bold italic versions of the font unless I explicitly indicate them as in

  \setmainfont{XITS}[ItalicFont=XITS-Italic,
  BoldFont=XITS-Bold, BoldItalicFont=XITS-BoldItalic]

The complaint that I find in the log file is

Package fontspec Info: Could not resolve font "XITS/BI" (it probably doesn't
(fontspec)             exist).

Package fontspec Info: Could not resolve font "XITS/B" (it probably doesn't
(fontspec)             exist).

Package fontspec Info: Could not resolve font "XITS/I" (it probably doesn't
(fontspec)             exist)

This seems strange, because with other fonts (e.g. Times New Roman, STIX Two Text, TeX Gyre Termes, etc.) fontspec can easily find the italic, etc font versions by itself. Furthermore, on my machine (Ubuntu linux with the upstream TeXLive), fc-match can find all versions of XITS:

fc-match XITS:italic
XITS-Italic.otf: "XITS" "Italic"

Furthermore, everything works just fine with xelatex.

Check/indicate

• [ ] Relevant for XeTeX
• [X] Relevant for LuaTeX
• [X] Issue tracker has been searched for similar issues?
• [ ] Links to discussion if appropriate

[wspr]

Thanks for taking the time to write this up. Resolving font variants like this is not a hard science. It may be that this cannot be done reliably. Regardless, this is not under the control of fontspec — if anything it is a luaotfload issue.