Problems with italics in other font when using roboto condensed

Question

I just realized that all italics are missing in the main text of my book manuscript (using \textit{}).

I narrowed the problem down to the use of Roboto Condensed as font.

\documentclass{scrbook} 

\usepackage[utf8]{inputenc}\usepackage[T1]{fontenc} 
\usepackage{fbb}           
%If I unclude the next line, the “text” will no longer be in italiscs
%\usepackage[condensed]{roboto} 

\begin{document}

Test \textit{text}.

\end{document}

When I uncomment the Roboto line (or just delete “condensed”) “text” will not be in italic any longer.

I had a look at older versions and recompiled one from mid 2019 when italics were still in it. After recompiling the italics are gone there, too. I reckon it has something to do with changes in TeX Live 2019. Any ideas how to approach the problem?

If it helps, here the part of the log, where the problems occure when roboto condensed is used:

(/usr/local/texlive/2020/texmf-dist/tex/latex/fbb/T1fbb-TLF.fd)

LaTeX Font Warning: Font shape `T1/fbb-TLF/c/n' undefined
(Font)              using `T1/fbb-TLF/m/n' instead on input line 112.

)) (/usr/local/texlive/2020/texmf-dist/tex/latex/l3backend/l3backend-pdftex.def
) (./Test.aux) (/usr/local/texlive/2020/texmf-dist/tex/latex/ly1/ly1ptm.fd)

LaTeX Font Warning: Font shape `T1/fbb-TLF/c/it' undefined
(Font)              using `T1/fbb-TLF/c/n' instead on input line 10.


LaTeX Font Warning: Font shape `T1/fbb-TLF/c/sl' undefined
(Font)              using `T1/fbb-TLF/c/it' instead on input line 12.

[1{/usr/local/texlive/2020/texmf-var/fonts/map/pdftex/updmap/pdftex.map}]
(./Test.aux)

LaTeX Font Warning: Some font shapes were not available, defaults substituted.

Answer 1

For unknown reasons, roboto.sty redefines \mddefault to be \mddefault@sf which, with the condensed option is c.

Since fbb doesn't provide the condensed series, you get font substitution.

Here's a fix that also avoids spurious warnings.

\documentclass{scrbook}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\DeclareFontShape{T1}{cmr}{c}{n}{<->ssub*cmr/m/n}{} % avoid a spurious warning

% first roboto to avoid other spurious warnings
\usepackage[condensed]{roboto}

\usepackage{fbb}

% fix the bad declaration made by roboto
\renewcommand{\seriesdefault}{m}

\begin{document}


Test \textit{text}.

\textsf{Condensed}

\end{document}

Answer 2

roboto forces the series default to condensed — imho a odd choice, if roboto is used only for sans serif —, but fbb doesn't support this series.

\documentclass{scrbook}

%\usepackage[utf8]{inputenc} % unneeded in new systems
\usepackage[T1]{fontenc}
\usepackage{fbb}
\usepackage[condensed]{roboto}

\makeatletter
\renewcommand\seriesdefault{\mddefault\@empty}
\makeatother
\begin{document}

Test \textit{text} \sffamily Text \textit{text}

\end{document}