LaTeX Font Warning - undefined font shape (LuaLaTeX math font)

Question

This might be related to why math fonts aren't showing up, but I encountered this error with LuaLaTeX math font.

The only issue showing up as a font is \mathbf not displaying bold font, so I assume the two are probably correlated.

For instance, here is some sample text and preamble information:

% preamble
    \RequirePackage{fontspec}
    \RequirePackage{unicode-math} 
    \unimathsetup{math-style=TeX}
    \RequirePackage[english]{babel}
    \defaultfontfeatures{Ligatures=TeX, Scale=MatchLowercase}
    \setmainfont{Minion Pro}
    \setsansfont{Myriad Pro}
    \setmonofont{Inconsolata Nerd Font}
    \unimathsetup{math-style=TeX}
    \setmathfont{Libertinus Math}

% text file
\documentclass{article}
\usepackage{random} % contains my fonts; I will provide a link to it
\begin{document}
\section{Testing Math Fonts}
Here is me trying to test out how math fonts work.
\[ 
   \text{Regular: } x + 1 = 2; \, \text{Bold: } \mathbf{x + 1 = 2}; \,  \text{Italic: }\mathit{x+1 = 2}
.\] 
 
\end{document}

And the following output shows italic font working, but not bold:

Coincidentally, I also happen to have this warning:

Full Logs

Therefore, I think the two are related - a font shape undefined error is causing \mathbf to not show up. In that case, how can I resolve the font shape error?

Answer 1

(too long for a comment, hence posted as an answer)

As I have already noted in a comment, I am unable to reproduce the missing-bold-math font issue you've encountered on my laptop, where I use MacOS 13.0.1 "Ventura" and MacTeX2022, with all updates applied.

There is separate issue that needs to be addressed, though. Since the serif text font (Minion Pro) and math font (Libertinus Math) are only somewhat close, but not exactly identical, you should be asking yourself why are you using the commands \mathbf and \mathit, as they load characters from the text font, not from the math font. To actually employ the glyphs of the Libertinus Math font, you should be using \symbf and \symit-- which are macros are provided by the unicode-math package -- instead of \mathbf and \mathit.

% !TEX TS-program = lualatex
\documentclass{article} % or some other suitable document classs
\RequirePackage[english]{babel}

%\RequirePackage{fontspec} % 'fontspec' is loaded automatically by 'unicode-math'
\RequirePackage{unicode-math} 
\unimathsetup{math-style=TeX}
\defaultfontfeatures{Ligatures=TeX, Scale=MatchLowercase}
\setmainfont{Minion Pro}
\setsansfont{Myriad Pro}
\setmonofont{Consolas} % I don't have the 'Inconsolata Nerd' font
%\unimathsetup{math-style=TeX} % no need to run the same command twice
\setmathfont{Libertinus Math}

\begin{document}
\begin{tabular}{lll}
Regular              & $xyz + 1 = 2$      & basic text and math font  \\
\textbf{Bold text}   & \textbf{x y z 1 2} & text-font bold glyphs \\
\textit{Italic text} & \textit{x y z 1 2} & text-font italic glyphs \\[1ex]
\textbf{Bold1}   & $\mathbf{xyz + 1 = 2}$ & math, but use text font glyphs \\
\textbf{Bold2}   & $\symbf{xyz + 1 = 2}$  & math, employ \verb+\symbf+ \\[1ex]
\textit{Italic1} & $\mathit{xyz + 1 = 2}$ & math, but use text font glyphs \\
\textit{Italic2} & $\symit{xyz + 1 = 2}$  & math, employ \verb+\symit+
\end{tabular}
\end{document}