Conflict beween pgfplots, babel package and babel tikzlibrary

Question

I came across a strange error today with a simple beamer frame that I am pretty sure worked a few weeks ago.

It seems to boil down (again) to active characters, which is something that \usetikzlibrary{babel} aims to fix. But here it is the other way around: if the library is used, it produces an error (File ended while scanning use of \pgfplots@addplotimpl@table@fromfile), while there is no problem when it is not used...

Interestingly, if the \begin{frame}...\end{frame} is removed, everything goes smoothly.

P.S. Older related posts do not seem to answer the problem...

This one deals with tikzmark: Clash between tikzmark, babel package (french) and babel tikzlibrary

This one deals with etoolbox: Conflict between french option, babel package, babel tikzlibrary and etoolbox package

MWE:

\documentclass{beamer}
\usepackage[french]{babel}
\usepackage{pgfplots}
\usetikzlibrary{babel} % No problem if commented

\begin{filecontents*}{test.csv}
   a,b,c,d,e
   1,2,3,4,5
   1,2,3,4,5
   1,2,3,4,5
   1,2,3,4,5
\end{filecontents*}

\begin{document}
\begin{frame} % Also no problem if commented!?
\begin{tikzpicture}
   \begin{axis}
      \addplot table[col sep=comma, x expr=\coordindex, y=a]{test.csv};
   \end{axis}
\end{tikzpicture}
\end{frame} % Also no problem if commented!?
\end{document}

Answer 1

The french babel package has a lot of incompatibilities due to the "activation" and redefinition of some special characters. In this case, what bites you is the activation of ;. Although the babel TikZ library suffices sometimes, it clearly fails inside a frame.

I see three possible solution:

1. Use lualatex. In this case, the special spacing needed by ;: it's done using the LUA engine, and your example works out-of-the-box.

2. Disable the ; shorthand at the start of the frame, adding \AtBeginEnvironment{frame}{\shorthandoff{;}} in the preamble; maybe in the future you need to add also : to the list (for what I know, babel-french activates ;:!?).

3. Disable shorthands for good with \usepackage[french, shorthand=off]{babel}

The solution (1) is the one that preserves all the special spacing rules...