log Missing character message from bend decimal angle

[kryde]

In recent Debian packaged PGF 3.1.1, a file

\documentclass[a4paper]{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\node (A) at (0,0) {A};
\node (B) at (15,0) {B};
\draw[bend left=0.9] (A) to (B);
\end{tikzpicture}
\end{document}

processed with "latex foo.tex" leaves in foo.log messages

Missing character: There is no . in font nullfont!
Missing character: There is no 9 in font nullfont!

This seems to be the .9 in the bend left. It seems decimals in such angle work correctly, but it could be good if the log was clean to them (or if it hints at anything fishy).

I struck this when some actual mistakes I'd made showed up in the log this way. I had bits like a stray semi in \draw ...; node[at end] ... so the "node" part did not take effect but gave Missing character n etc. Or a harmless bit like \foreach ... { }; where the final ; is unnecessary and likewise showed as Missing character.

[hmenke]

Well spotted 👍 Fixed in 36803f7.

Meanwhile you can backport the fix using

\documentclass[a4paper]{article}
\usepackage{tikz}

\makeatletter

\tikzoption{bend left}[]{%
  \def\pgf@temp{#1}%
  \ifx\pgf@temp\pgfutil@empty%
  \else%
    \pgfmathsetmacro\tikz@to@bend{#1}%
  \fi%
  \let\tikz@to@out=\tikz@to@bend%
  \pgfmathsetmacro\tikz@to@in{180-\tikz@to@out}%
  \tikz@to@switch@on%
  \tikz@to@relativetrue%
}

\makeatother

\begin{document}
\begin{tikzpicture}
\node (A) at (0,0) {A};
\node (B) at (15,0) {B};
\draw[bend left=0.9] (A) to (B);
\end{tikzpicture}
\end{document}

[hmenke]

In LuaTeX you can also make the “Missing character” a hard error, so you don't have to rely on chance to look in the logfile. The following is one single file, but split into three code blocks because GitHub doesn't support mixed syntax highlighting.

\documentclass[a4paper]{article}
\usepackage{tikz}
\usepackage{luacode}
\begin{luacode}

local function glyph_error(id, char)
    local fontname = tex.fontname(tex.fontidentifier(id))
    local message = string.format(
        "Missing character: There is no %s (U+%04X) in font %s!",
        utf.char(char), char, fontname)
    tex.error(message)
end

luatexbase.add_to_callback("glyph_not_found", glyph_error, "glyph_error")

\end{luacode}
\begin{document}
\begin{tikzpicture}
\node (A) at (0,0) {A};
\node (B) at (15,0) {B};
\draw[bend left=0.9] (A) to (B);
\end{tikzpicture}
\end{document}

[kryde]

Ah, beaut.

[stefanct]

uhm, but what about bend right though? asking for a diagram ;)
it has the same problem but the fix doesn't work (alone), i guess because of the code that negates the input?

Edit: In theory this works for bend right=x, but it breaks if bend right is used w/o a dimension/factor.

\tikzoption{bend right}[]{%
  \def\pgf@temp{#1}%
  \ifx\pgf@temp\pgfutil@empty%
  \else%
    \pgfmathsetmacro\tikz@to@bend{-#1}%
  \fi%
  \let\tikz@to@out=\tikz@to@bend%
  \pgfmathsetmacro\tikz@to@in{180-\tikz@to@out}%
  \tikz@to@switch@on%
  \tikz@to@relativetrue%
}

[muzimuzhi]

@stefanct The latest code (since v3.1.6a) is different to what you shown, and it seems ok, see

pgf/tex/generic/pgf/frontendlayer/tikz/libraries/tikzlibrarytopaths.code.tex

Lines 42 to 53 in b79c4c5

	\tikzoption{bend right}[]{%
	\def\pgf@temp{#1}%
	\ifx\pgf@temp\pgfutil@empty%
	\else%
	\pgfmathsetmacro\tikz@to@bend{#1}%
	\fi%
	% Now, negate
	\pgfmathsetmacro\tikz@to@out{-(\tikz@to@bend)}
	\pgfmathsetmacro\tikz@to@in{180-(\tikz@to@out)}
	\tikz@to@switch@on%
	\tikz@to@relativetrue%
	}

An example will better demonstrate your problem.

[stefanct]

Right, because of 357bc05 thanks to #837. My installation is just too old and I fell for a github UI "feature", sorry for the noise.