latexmk says fontspec/Path is unknown

Question

I have the following document, which uses fonts stored in a fonts/ directory (specifically several subdirectories of fonts/), as well as defined font subfamilies. I'm trying to compile it into a PDF using latexmk:

\documentclass[10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[margin=0.75in]{geometry}


\usepackage[colorlinks=true]{hyperref}
\usepackage{metalogo}

\usepackage{fontspec}
\setmainfont{FRABK.TTF}[
  ItalicFont = FRABKIT.TTF,
  BoldFont = FRAMD.TTF,
  BoldItalicFont = FRAMDIT.TTF,
  FontFace = {db}{n}{ Font = FRADM.TTF, Path = fonts/franklin-gothic/ },
  FontFace = {db}{i}{ Font = FRADMIT.TTF, Path = fonts/franklin-gothic/ },
  Path = fonts/franklin-gothic/
]
\setsansfont{CGOR45W.TTF}[
  ItalicFont=CGOR46W.TTF,
  BoldFont=CGOR65W.TTF,
  BoldItalicFont=CGOR66W.TTF,
  Path = fonts/cg-omega/
]
\setmonofont{CONSOLA.TTF}[
  ItalicFont=CONSOLAI.TTF,
  BoldFont=CONSOLAB.TTF,
  BoldItalicFont=CONSOLAZ.TTF,
  Path = fonts/consolas/
]
\newcommand{\lmr}{\fontfamily{lmr}\selectfont} % Latin Modern Roman
\newcommand{\lmss}{\fontfamily{lmss}\selectfont} % Latin Modern Sans
\newcommand{\lmtt}{\fontfamily{lmtt}\selectfont} % Latin Modern Mono


\begin{document}


\section{Foo}
\fontseries{db}\selectfont
Demibold text \\
\normalfont
\textbf{Medium text} \\
Normal text


\noindent
  \hrulefill \par
\noindent
  \hypersetup{linkcolor=gray}
  \small
  \url{http://www.example.org/} \hfill \textbf{Date}


\end{document}

Since I'm using fontspec, this would require xelatex. However, when I run latexmk -pdf -xelatex main.tex, I receive:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
! LaTeX error: "kernel/key-unknown"
!
! The key 'fontspec/Path' is unknown and is being ignored.
!
! See the LaTeX3 documentation for further information.
!
! For immediate help type H <return>.
!...............................................

l.17 ]

? h
|'''''''''''''''''''''''''''''''''''''''''''''''
| The module 'fontspec' does not have a key called fontspec/Path'.
| Check that you have spelled the key name correctly.
|...............................................

Why is fontspec/Path unknown, and how can I get it to be recognized? Is my latexmk invocation incorrect, perhaps causing it not to use xelatex at a time when it should?

More generally, could this be alleviated by better methods of organizing the font definitions or how the document is compiled?

Answer 1

Per Will Robertson's comment, actually, fontspec can find the font; it just doesn't need to be told the location twice. Applying the following diff got rid of the error:

-       FontFace = {db}{n}{ Font = FRADM.TTF, Path = fonts/franklin-gothic/ },
-       FontFace = {db}{i}{ Font = FRADMIT.TTF, Path = fonts/franklin-gothic/ }
+       FontFace = {db}{n}{ Font = FRADM.TTF },
+       FontFace = {db}{i}{ Font = FRADMIT.TTF }

Full example

\documentclass[10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[margin=0.75in]{geometry}


\usepackage[colorlinks=true]{hyperref}
\usepackage{metalogo}

\usepackage{fontspec}
\setmainfont{FRABK.TTF}[
  ItalicFont = FRABKIT.TTF,
  BoldFont = FRAMD.TTF,
  BoldItalicFont = FRAMDIT.TTF,
  FontFace = {db}{n}{ Font = FRADM.TTF },
  FontFace = {db}{i}{ Font = FRADMIT.TTF },
  Path = fonts/franklin-gothic/
]
\setsansfont{CGOR45W.TTF}[
  ItalicFont=CGOR46W.TTF,
  BoldFont=CGOR65W.TTF,
  BoldItalicFont=CGOR66W.TTF,
  Path = fonts/cg-omega/
]
\setmonofont{CONSOLA.TTF}[
  ItalicFont=CONSOLAI.TTF,
  BoldFont=CONSOLAB.TTF,
  BoldItalicFont=CONSOLAZ.TTF,
  Path = fonts/consolas/
]
\newcommand{\lmr}{\fontfamily{lmr}\selectfont} % Latin Modern Roman
\newcommand{\lmss}{\fontfamily{lmss}\selectfont} % Latin Modern Sans
\newcommand{\lmtt}{\fontfamily{lmtt}\selectfont} % Latin Modern Mono


\begin{document}


\section{Foo}
\fontseries{db}\selectfont
Demibold text \\
\normalfont
\textbf{Medium text} \\
Normal text


\noindent
  \hrulefill \par
\noindent
  \hypersetup{linkcolor=gray}
  \small
  \url{http://www.example.org/} \hfill \textbf{Date}


\end{document}

Answer 2

Simplest answer:

Copy the font files to ~/.fonts/, re-run fc-cache, then load them by their human-readable names.

More Comprehensive, Revised:

My first answer missed that your problem was your demibold fonts not working. Here’s how you do that. To test this, I put symlinks for all the Libertine fonts with slightly-altered names in a fonts/ directory so that there would be no possibility of XeLaTeX or LuaLaTeX finding them in their original locations.

\documentclass{article}
\usepackage{iftex}

\ifPDFTeX
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{cmbright}
%% Load without Biolinum, or it will replace CM Bright,
%% and without sb, or it will replace bold:
\usepackage[libertine]{libertine}

\else % Assume a Unicode engine.
\usepackage{fontspec}

%% COPY and RENAME the Libertine files to test the engine's ability to find them.
\setmainfont{Libertine_R.otf}[
              Path = fonts/,
              FontFace = {sb}{n}{ Font = Libertine_RZ.otf},
              FontFace = {sb}{it}{ Font = Libertine_RZI.otf},
              BoldFont = {Libertine_RB.otf},
              ItalicFont = {Libertine_RI.otf},
              BoldItalicFont = {Libertine_RBI.otf},
            ]
\defaultfontfeatures{Scale=MatchLowercase}
\setsansfont[ FontFace = {sb}{n}{CMU Bright SemiBold},
              FontFace = {sb}{it}{CMU Bright SemiBold Oblique},
            ]{CMU Bright}

\fi         % \ifPDFTeX

\DeclareOldFontCommand{\sbseries}{\fontseries{sb}\selectfont}{\mathbf}
\DeclareTextFontCommand{\textsb}{\sbseries}

\begin{document}

\framebox[10cm][s]{
\rmfamily \makebox[2.5cm][c]{Normal} \makebox[2.5cm][c]{\mdseries Medium} \makebox[2.5cm][c]{\sbseries Semibold} \makebox[2.5cm][c]{\bfseries Bold} \normalfont
} \par
\framebox[10cm][s]{
\makebox[2.5cm][c]{\textsf{Normal}} \makebox[2.5cm][c]{\textsf{\textmd{Medium}}}\makebox[2.5cm][c]{\textsf{\textsb{Semibold}}} \makebox[2.5cm][c]{\textsf{\textbf{Bold}}}
}

\end{document}

Note that there’s no need to declare \inputenc in either, because they accept UTF-8 by default, and \newfontfamily exists to do what you wanted with \lmr. Also, the usual series name for semibold fonts is {sb}.

Additional Notes

There are a few differences from your example, but they're minor. As in the original, this solution puts the custom fonts in a fonts/ subdirectory. The \ifPDFTeX block is only there so the example will compile on PDFLaTeX and provide reference output. Finally, the \defaultfontfeatures command has the cosmetic effect of scaling all the fonts loaded by fontspec to the same x-height.