Fontspec package can't find "Latin Modern Mono" on MacOS/MacTeX

Question

I've been using the fontspec package with XeTeX to load fonts. Here is a simple example that doesn't work:

\documentclass[12pt,a4paper]{book}
\usepackage{fontspec}
\begin{document}
\setmainfont{Latin Modern Mono}
\end{document}

This works fine on Windows and Linux (on Linux I had to update my FontConfig settings). On MacOS with MacTeX I get this error:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
! fontspec error: "font-not-found"
!
! The font "Latin Modern Mono" cannot be found.
!
! See the fontspec documentation for further information.
!
! For immediate help type H <return>.
!...............................................

l.4 \setmainfont{Latin Modern Mono}

If I copy the font file to ~/Library/Fonts like this:

cp /usr/local/texlive/2017/texmf-dist/fonts/opentype/public/lm/lmmono12-regular.otf ~/Library/Fonts/

It fixes the problem, however that is not ideal for my situation because other users use this set up and I don't want them to have to worry about copying fonts around, especially since the fonts are already existing in the texlive directory. My understanding is that XeTeX searches both the macOS font folders and the texlive installation folders (http://mactex-wiki.tug.org/wiki/index.php/Font_Selection#Using_fonts_with_XeTeX).

How does fontspec resolve fonts on MacOS? Does MacTeX use FontConfig on MacOS or something else?

I have FontConfig installed on my Mac for other reasons, is this an issue?

System Information:

macOS 10.13.1 - 2011 Macbook Air

XeTeX 3.14159265-2.6-0.99998 (TeX Live 2017)

Answer 1

It appears this is a case of RTFM (http://ctan.mirrors.hoobly.com/macros/latex/contrib/fontspec/fontspec.pdf). According to the latest fontspec documentation this isn't possible with XeTeX without copying the fonts to ~/Library/Fonts.

XeTeX and LuaTEX also allow fonts to be loaded by file name instead of font name. When you have a very large collection of fonts, you will sometimes not wish to have them all installed in your system’s font directories. In this case, it is more convenient to load them from a different location on your disk. This technique is also necessary in XeTeX when loading OpenType fonts that are present within your TEX distribution, such as /usr/local/texlive/2013/texmf- dist/fonts/opentype/public. Fonts in such locations are visible to XeTeX but cannot be loaded by font name, only file name; LuaTEX does not have this restriction.

Answer 2

I have been using for some time symlinks in my ~/Library/Fonts. Here is a view of that repertory from Emacs:

Then, consider test document

\documentclass[12pt,a4paper]{book}
\usepackage{fontspec}
\XeTeXtracingfonts1
\setmainfont{Latin Modern Mono}
\begin{document}
Hello
\end{document}

It produces expected result, and the log file contains things like

Requested font "Latin Modern Mono" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
Requested font "Latin Modern Mono/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
\g__fontspec_family_LatinModernMono_int=\count180
Requested font "Latin Modern Mono/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
Requested font "Latin Modern Mono/BI/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono10-italic.otf
Requested font "Latin Modern Mono/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
Requested font "Latin Modern Mono/B/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
.................................................
. fontspec info: "no-font-shape"
. 
. Could not resolve font "Latin Modern Mono/B" (it probably doesn't exist).
.................................................
Requested font "Latin Modern Mono/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
Requested font "Latin Modern Mono/I/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono10-italic.otf
Requested font "Latin Modern Mono/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
Requested font "Latin Modern Mono/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf
Requested font "Latin Modern Mono/I/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono10-italic.otf
Requested font "Latin Modern Mono/I/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono10-italic.otf
Requested font "Latin Modern Mono/BI/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono10-italic.otf
Requested font "Latin Modern Mono/BI/OT" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono10-italic.otf
.................................................
. fontspec info: "defining-font"
. 
. Font family 'LatinModernMono(0)' created for font 'Latin Modern Mono' with
. options [Ligatures=TeX].
.  
.  This font family consists of the following NFSS series/shapes:
.  
. - 'normal' (m/n) with NFSS spec.: <->"Latin Modern
. Mono/OT:script=latn;language=DFLT;mapping=tex-text;"
. - 'small caps'  (m/sc) with NFSS spec.: 
. - 'italic' (m/it) with NFSS spec.: <->"Latin Modern
. Mono/I/OT:script=latn;language=DFLT;mapping=tex-text;"
. - 'italic small caps'  (m/itsc) with NFSS spec.: 
. - 'bold italic' (bx/it) with NFSS spec.: <->"Latin Modern
. Mono/BI/OT:script=latn;language=DFLT;mapping=tex-text;"
. - 'bold italic small caps'  (bx/itsc) with NFSS spec.: 
.................................................
LaTeX Info: Redefining \rmfamily on input line 4.
Requested font "Latin Modern Mono/OT:script=latn;language=DFLT;mapping=tex-text
;" at 12.0pt
 -> /Users/xXx/Library/Fonts/TeXOpenType/public/lm/lmmono12-regular.otf

By the way, this does not perturbate recent luaotfload: the LuaTeX database will not contain duplicate entries as it was the case perhaps two years ago (i.e. in 2015). I forgot the details.