Define dependencies when using tikz externalize

Question

At the beginning of my document I have \input{tikzcommands} where tikzcommands.tex contains global settings that I want to use in the TikZ pictures. For example, in this file I define some styles.

The problem, when using the externalize library it doesn't recognizes when something changed with the tikzcommands.tex. I tried to add something like \tikzpicturedependsonfile{tikzcommands.tex} at the beginning of the TikZ environment, but it didn't help.

What is the right way to make figureA.tex (which is included using input) depended on a settings file tikzcommands.tex?

EDIT: Due to the comment of @Psirus I know that I'm doing something wrong. But I still don't manage to have the desired behavior, even when trying to use mode=list and make. Here is my original pseudo MWE.

First, I load TikZ

\usepackage{tikz}
\usetikzlibrary{snakes,calc,decorations.pathreplacing,patterns}

Then, I have the following

\makeatletter
\IfFileExists{tikzexternal.sty}
{%
  \usetikzlibrary{external}%
  \tikzexternalize%
  \tikzsetexternalprefix{figures/cache/}%
  \renewcommand{\todo}[2][]{%
    \tikzexternaldisable\@todo[##1]{##2}\tikzexternalenable}%
}%
{%
  % Empty else case
}%
\makeatother

Which checks is externalize is available, or not. This part I have to make the code compatible with older distributions of pgf which do not support the externalize package.

Then I have an included file tikzcommands.tex which contains (among other things)

\tikzset{
        robot/.style={thick,fill=green!#1},
        obstacle/.style={fill=red!80,thick}
}

Finally in the document's body I have inputs of the following form:

\input{./figures/figureA} 

In figureA I use the styles robot and obstacle.

I want to use externalize in such a way that even when I just change the file tikzcommands.tex the figures which depend on it will be re-compiled.

I understand that I have to:

1. Change the loading of the externalize package.
2. Add something before each input which depends on the tikzcommands.tex
3. Probably change the building workflow. Currently I'm using latexmk alone.

I tried several combinations but nothing worked for me. I hope someone could draw the way to accomplish this.

Answer 1

First off, I don't know latexmk, so my solution doesn't integrate nicely, but I guess you can adapt my crude Makefile to your latexmk logic.

The main file, here main.tex:

\documentclass{scrartcl}

\usepackage{tikz}

\makeatletter
\IfFileExists{tikzexternal.sty}
{%
  \usetikzlibrary{external}%
  \tikzset{external/mode=list and make}
  \tikzexternalize%
  \tikzsetexternalprefix{figures/cache/}%
}%
{%
  % Empty else case
}%
\makeatother

\input{tikzcommands}

\begin{document}
    \input{./figures/figureA}
\end{document}

Instead of generating the pictures directly, pdflatex now writes a main.makefile for the images. The dependency on tikzcommands.tex is set in the picture file figure/figureA.tex:

\begin{tikzpicture}
    \tikzpicturedependsonfile{tikzcommands.tex}
    \draw[myRectangle] (0,0) rectangle (2,2);
\end{tikzpicture}

And to make the example complete, a dummy tikzcommands.tex:

\tikzset{
        myRectangle/.style={thick}
}

Now you can run make -f main.makefile to make the pictures, and only rebuild them when their sources or tikzcommands.tex changes. A very crude Makefile would be:

main.pdf: main.tex
    pdflatex main.tex;
    make -f main.makefile
    latexmk -pdf main.tex

But this runs pdflatex once unnecessarily, and really displays my ignorance regarding latexmk. I'm sure you can add the line make -f main.makefile to the latexmk logic so that it is run after a first pass of pdflatex.