Incompatibility between Tikz-cd and German language under Polyglossia

Question

The following MWE shows a incompatibility between tikz-cd and polyglossia:

\documentclass{report}
\usepackage{polyglossia}
\setmainlanguage{german}
\usepackage{tikz-cd}
\begin{document}
\begin{tikzcd}
     B \arrow{rr}{f} && C\
    &A \arrow{ul}{\phi} \arrow[swap]{ru}{\psi}
  \end{tikzcd}
\end{document}

I have seen a few solutions when the problems come from babel like this one here, but the solution does not work for polyglossia under xelatex.

The error is:

! Package pgfkeys Error: I do not know the key '/tikz/"{f}"{}' and I am going t
o ignore it. Perhaps you misspelled it.

I am running TeXLive 2018 on this machine. So it looks like it is the problem ... — Paulo Ney, Aug 06 '20 at 18:32

score 2 · Accepted Answer · answered Aug 06 '20 at 22:50

The german language file makes " active, and older tikz-cd don't expect that and break. But if you just load tikz-cd before polyglossia (thus freezing " as catcode-12), your code will work.

tikz-cd diagrams also use lots of " in them, so if you'll use them you also need to make " an ordinary character there. The babel TikZ library does that for you (loading the babel library is usually a good idea).

\documentclass{report}
\usepackage{tikz-cd} % Load before polyglossia
\usetikzlibrary{babel} % load to use " in pictures
\usepackage{polyglossia}
\setmainlanguage{german}
\begin{document}
\begin{tikzcd}
   B \arrow{rr}{f} && C\
  &A \arrow{ul}{\phi} \arrow[swap]{ru}{\psi}
\end{tikzcd}
\begin{tikzcd}
 A \arrow[rd] \arrow[r, "\phi"] & B \
                                & C
\end{tikzcd}
\end{document}

Incompatibility between Tikz-cd and German language under Polyglossia

1 Answers1