a bug with calc and ehhline together

Question

Days before, I was dealing with the problem of drawing horizontal lines between colored multirow cell with \hhline. I tried two method and took the second at last. But I found there is a bug in the first method if calc is loaded.

All things are in my example code. Comment the calc package, the vertical line (red and teal ones) below the third row will be shown normally.

\documentclass{article}
\usepackage[table]{xcolor}
\usepackage{tikz}
\usepackage{multirow}
\usepackage{colortbl}
\usepackage{ehhline}
% \usepackage{calc} % make method 1 not work

%% vertical line
% vertical colored line #1 color #2 width
\newcommand{\vsl}[2]{\color{#1}\vrule width #2}
% colored solid line pattern
% #1 color #2 width #3 height
\newcommand{\hsp}[3]{\hbox{\textcolor{#1}{\rule{#2}{#3}}}}
% #1 top fill #2 bottom fill
\newcommand{\leaderfill}[1]{%
  \xleaders\hbox{%
    \vbox{\baselineskip=0pt\lineskip=0pt#1}%
  }\hfill%
}
% #1 color #2 height
\newcommand{\sfill}[2]{%
  \leaderfill{\hsp{#1}{0.1pt}{#2}}%
}
%% vline settings
% #1 rule width #2 color
\newcommand{\setvline}[2]{%
  \global\setlength\arrayrulewidth{#2}\arrayrulecolor{#1}%
}

\begin{document}
\begin{tabular}{
  !{\vsl{red}{5pt}}c
  !{\vsl{teal}{5pt}}p{0.5cm}
  !{\vsl{blue}{3pt}}
}
% row 1
  \cellcolor{gray}
  & \cellcolor{yellow}\\
\hhline{
  ~ % blank in merged cell
  !{\sfill{black}{3pt}}
}
% row 2
  \cellcolor{gray}
  & \cellcolor{yellow}\\
\hhline{
  !{\sfill{gray}{3pt}} % overlap the vertical line
  !{\sfill{black}{3pt}}
}
% row 3
  \cellcolor{gray} third row
  & \cellcolor{orange}\\
% first method: set arrayrulewidth and arraycolor
% not work with calc
\hhline{
  >{\setvline{red}{5pt}}|
  !{\sfill{gray}{3pt}}
  >{\setvline{teal}{5pt}}|
  !{\sfill{black}{3pt}}
}
% row 4
  \cellcolor{gray}\tikz[->, baseline=-.5ex] \draw (0, 0) -- (-1ex, 1ex);
%   load calc
  not load
  & \cellcolor{pink}\\
% second method: use box
\hhline{
  >{\vsl{red}{5pt}}
  !{\sfill{gray}{3pt}}
  >{\vsl{teal}{5pt}}
  !{\sfill{black}{3pt}}
}
% row 5
  \cellcolor{gray}\multirow{-5}*{}
  & \cellcolor{cyan}\\
\end{tabular}
\end{document}

Answer 1

The MWE can be simplified to

\documentclass{article}
\usepackage[table]{xcolor}
\usepackage{ehhline}

\usepackage{stackengine}

\begin{document}
\begin{tabular}{p{0.5cm} !{\color{yellow}\vrule width 5pt} p{0.5cm}}
  a & b \\
  \hhline{
    -
    >{\global\setlength\arrayrulewidth{5pt}\arrayrulecolor{yellow}}|
    >{\global\setlength\arrayrulewidth{.4pt}} -
  }
  c & d
\end{tabular}
\end{document}

From question comments, it is calc, loaded by stackengine, that redefines \setlength and forbids the never-supported syntax \global\setlength.

To change a length globally, you can use

\global\deflength{<length>}{<glue expression>}

where \deflength is defined by etoolbox package.

Or, you can avoid the need to change \arrayrulewidth globally in >{...} by using the new hhline preamble V[<color>]{<width>} from my previous answer.

Inside \hhline, V[<color>]{<width>} acts like | with specific color and width. A full example:

\documentclass{article}
\usepackage[table]{xcolor}
\usepackage{ehhline}

\usepackage{stackengine}

\usepackage{xpatch} % or etoolbox
\usepackage{xparse}

\makeatletter
% based on \vline from latex2e
\def\HHvline#1{\vrule\@width#1}

\AtBeginDocument{
  \@ifpackageloaded{colortbl}{
    % based on \ifx\@tempb|...\else part of \HH@loop from colortbl.sty
    \NewDocumentCommand{\HH@preamble@V}{ m o m }{%
      \if@tempswa
        \ifx\CT@drsc@\relax
          \HH@add{\hskip\doublerulesep}%
        \else
          \HH@add{{\CT@drsc@\vrule\@width\doublerulesep}}%
        \fi
      \fi
      \@tempswatrue
      \IfNoValueTF{#2}
        {\HH@add{{\CT@arc@{\HHvline{#3}}}}}
        {\HH@add{{\color{#2}\HHvline{#3}}}}%
      \HH@let V%
    }
    \xpatchcmd\HH@loop
      {\PackageWarning{hhline}}
      {%
        \ifx\@tempb V% V[<color>]{<width>}
          \let\next\HH@preamble@V
        \else
        \PackageWarning{hhline}%
      }
      {}{\fail}
  }{
    % based on \ifx\@tempb|...\else part of \HH@loop from hhline.sty
    \NewDocumentCommand{\HH@preamble@V}{ m o m }{%
      \if@tempswa\HH@add{\hskip\doublerulesep}\fi\@tempswatrue
      \IfNoValueTF{#2}
        {\HH@add{\@tempc{\HHvline{#3}}\@tempc}}
        {\HH@add{\@tempc{\color{#2}\HHvline{#3}}\@tempc}}%
      \HH@let V%
    }
    \xpatchcmd\HH@loop
      {\PackageWarning{hhline}}
      {%
        \ifx\@tempb V% V[<color>]{<width>}
          \let\next\HH@preamble@V
        \else
      }
      {}{\fail}
  }
  \xpatchcmd\HH@loop
    {\fi\fi\fi}
    {\fi\fi\fi\fi}
    {}{\fail}
}
\makeatother

\begin{document}
\begin{tabular}{p{0.5cm} !{\color{yellow}\vrule width 5pt} p{0.5cm}}
  a & b \\
  \hhline{- V[yellow]{5pt} >{\arrayrulecolor{yellow}}-}
  c & d
\end{tabular}
\end{document}