pdflatex hangs on a pending '['

Question

The tool pdflatex hangs when I leave a '[' pending after the beginning of a TikZ picture. The same thing happens when I use for instance MikTeX that uses pdflatex under the hood. It happens both on Linux and on Windows.

Minimal example:

\documentclass{article}
\usepackage{tikz}
\begin{document}
  \begin{tikzpicture}[
    \draw[blue] (0,0) -- (1,1);
  \end{tikzpicture}
\end{document}

We're using pdflatex for batch processing. What can we do to avoid it from hanging?

score 6 · Accepted Answer · answered Nov 13 '16 at 01:03

6

the default definition of \tikz@signal@path is a little dangerous (a "quark" in expl3 code terminology) I think it's safe to use a slightly less dangerous \protected definition

\documentclass{article}
\usepackage{tikz}
\makeatletter
\protected\def\tikz@signal@path{\tikz@signal@path}%
\makeatother
\begin{document}
  \begin{tikzpicture}[
    \draw[blue] (0,0) -- (1,1);
  \end{tikzpicture}
\end{document}

which causes tex to show an error rather than loop.

! Use of \tikz@@scope@env doesn't match its definition.

answered Nov 13 '16 at 01:03

David Carlisle

757,742

Thanks! I've added it to a fixed pre-amble and it works like a charm! – Klaas van Aarsen Nov 13 '16 at 09:06
I'm currently fixing bugs in PGF, but we can't fix this one using e-TeX protection because TikZ still supports DVI mode (for whatever reason). – Henri Menke Dec 29 '18 at 01:13
@Henri protected is an etex not pdftex feature so available in dvi mode – David Carlisle Dec 29 '18 at 09:04
@DavidCarlisle But there are engines which are not e-TeX and use DVI mode. – Henri Menke Dec 29 '18 at 09:44
Yes but anyone with access to tex has access to etex so not using etex extensions is a very unnecessary constraint these days – David Carlisle Dec 29 '18 at 12:18
1

After a recent revision this no longer loops but fail with ! Undefined control sequence. because an additional assignment has been added in \path. – Henri Menke Apr 06 '19 at 00:37

pdflatex hangs on a pending '['

1 Answers1

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