Btukfyl

I don't know if this a problem with my local TeX-Distribution (macTeX 2018) or with tikz-cd itself, how ever: I can't compile basic examples from the tikz-cd manual, like this:

    documentclass{standalone}

    usepackage[utf8]{inputenc}

    usepackage[ngerman]{babel}

    usepackage{xcolor}



    usepackage[T1]{fontenc}

    usepackage{lmodern}



    usepackage{amsmath, amssymb}





    usepackage{tikz-cd}



    begin{document}



    begin{tikzcd}

        A arrow[r, "phi"] arrow[d, red]

                & B arrow[d, "psi" red] \

        C arrow[r, red, "eta" blue]

            &D end{tikzcd}



    end{document}

The resulting output is

And the errors messages inside the log start with this error message:

    ! Argument of language@active@arg" has an extra }.

<inserted text> 

                par 

l.18        &D end{tikzcd}



I've run across a `}' that doesn't seem to match anything.

For example, `defa#1{...}' and `a}' would produce

this error. If you simply proceed now, the `par' that

I've just inserted will cause me to report a runaway

argument that might be the root of the problem. But if

your `}' was spurious, just type `2' and it will go away.



Runaway argument?

! Paragraph ended before language@active@arg" was complete.

<to be read again> 

                   par 

l.18        &D end{tikzcd}

Any ideas what the problem might be? The macTeX-Distribution is complete and up-to-date as of april 4th 2019.

To solve the your question you can add usetikzlibrary{babel} always confirming that you can use usepackage[ngerman]{babel}. Now there is no errors.

    documentclass{standalone}

    usepackage[utf8]{inputenc}

    usepackage[ngerman]{babel}

    usepackage{xcolor}

    usepackage[T1]{fontenc}

    usepackage{lmodern}

    usepackage{amsmath, amssymb}

    usepackage{tikz-cd}

    usetikzlibrary{babel}

    begin{document}

    begin{tikzcd}

        A arrow[r, "phi"] arrow[d, red]

                & B arrow[d, "psi" red] \

        C arrow[r, red, "eta" blue]

            &D 

    end{tikzcd}

    end{document}