latexmk configuration for compiling gnuplottex figures using epslatex terminal

When I used gnuplot with $\LaTeX$ in the past, I was always using a custom Makefile to compile the gnuplot figures. I recently came across the gnuplottex package and wanted to give it a try.

I quickly came across a problem: when using the epslatex terminal, latexmk would end up in an infinite loop trying to compile the document. I prepared a demo for this:

\documentclass{standalone}
\usepackage{color}
\usepackage{gnuplottex}

\begin{document}
\noindent
\begin{gnuplot}[terminal=epslatex]
    set samples 100
    system("sleep 1.2")  # wait 1.2 seconds
    plot [0:2*pi] sin(x)
\end{gnuplot}
\end{document}

$ latexmk --version

Latexmk, John Collins, 20 November 2021. Version 4.76

$ cat latexmkrc
$pdf_mode = 1;
$pdflatex = 'pdflatex --shell-escape %O %S';

$ latexmk demo
...
Rule 'pdflatex': File changes, etc:
   Changed files, or newly in use since previous run(s):
      'demo-gnuplottex-fig1.eps'
Latexmk: Maximum runs of pdflatex reached without getting stable files
...

The problem is that the generated .eps file contains a timestamp, so its hash keeps changing:

$ grep 2023 demo-gnuplottex-fig1.eps
%%CreationDate: Mon Mar 20 16:25:44 2023
  /CreationDate (Mon Mar 20 16:25:44 2023)

I have fixed this problem by adding extra configuration to my latexmkrc. I have also added clean_ext to clean up gnuplottex-generated files when running latexmk -c:

$pdf_mode = 1;
# enable shell escape - needed for gnuplottex
$pdflatex = 'pdflatex --shell-escape %O %S';

# gnuplottex would make latexmk go into an infinite loop
$hash_calc_ignore_pattern{'eps'} = '^%%CreationDate: |CreationDate \(';

# gnuplottex cleanup
$clean_ext = "$clean_ext %R.gnuploterrors %R-gnuplottex-*";