new array.sty and colortbl.sty incompatibility?

Question

I just upgraded my texlive distribution and can no longer insert space in table rows using \\[x pt] syntax when colortbl is loaded.

It seems that recent changes to array.sty might be the problem as this is the only package to change recently.

Can anyone suggest a workaround?

MWE

\listfiles
\documentclass{article}
\usepackage{colortbl}
\begin{document}
\begin{tabular}{l}
  \hline
  No space below with \texttt{colortbl.sty} loaded. \\[10mm]
  \hline
\end{tabular}
\end{document}

File versions in use:

 article.cls    2014/09/29 v1.4h Standard LaTeX document class
  size10.clo    2014/09/29 v1.4h Standard LaTeX file (size option)
colortbl.sty    2012/02/13 v1.0a Color table columns (DPC)
   array.sty    2018/04/07 v2.4g Tabular extension package (FMi)
   color.sty    2016/07/10 v1.1e Standard LaTeX Color (DPC)
   color.cfg    2016/01/02 v1.6 sample color configuration
  pdftex.def    2018/01/08 v1.0l Graphics/color driver for pdftex

Answer 1

sorry patching is a bit tricky so I post a new colortbl.sty below, can you test this

%%
%% This is file `colortbl.sty',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% colortbl.dtx  (with options: `package')
%% 
%%
%% Source File: `colortbl.dtx'.
%% Copyright 1996 1998 1999 2012 David Carlisle
%%
%% This file may be distributed under the terms of the LPPL.
%% See readme for details.
%%
\NeedsTeXFormat{LaTeX2e}[1995/06/01]
\ProvidesPackage{colortbl}
          [2012/02/13 v1.0a Color table columns (DPC) new array fix]
\edef\@tempa{%
  \noexpand\AtEndOfPackage{%
    \catcode`\noexpand\^^A\the\catcode`\^^A\relax}}
\@tempa
\catcode`\^^A=\catcode`\%
\DeclareOption{debugshow}{\catcode`\^^A=9 }
\DeclareOption*{\PassOptionsToPackage\CurrentOption{color}}
\ProcessOptions
\RequirePackage{array,color}
\def\@classz{\@classx
   \@tempcnta \count@
   \prepnext@tok
\expandafter\CT@extract\the\toks\@tempcnta\columncolor!\@nil
   \@addtopreamble{%
    \setbox\z@\hbox\bgroup\bgroup
      \CT@everycr{}%
      \ifcase \@chnum
      \hskip\stretch{.5}\kern\z@
      \d@llarbegin
      \insert@column
      \d@llarend\do@row@strut\hskip\stretch{.5}\or
      \d@llarbegin \insert@column \d@llarend\do@row@strut \hfill \or
      \hfill\kern\z@ \d@llarbegin \insert@column \d@llarend\do@row@strut \or
   $\vcenter
   \@startpbox{\@nextchar}\insert@column \@endpbox $\or
   \vtop \@startpbox{\@nextchar}\insert@column \@endpbox \or
   \vbox \@startpbox{\@nextchar}\insert@column \@endpbox
  \fi
 \egroup\egroup
\begingroup
  \CT@setup
  \CT@column@color
  \CT@row@color
  \CT@cell@color
  \CT@do@color
\endgroup
        \@tempdima\ht\z@
        \advance\@tempdima\minrowclearance
        \vrule\@height\@tempdima\@width\z@
        \unhbox\z@}%
  \prepnext@tok}
\def\CT@setup{%
  \@tempdimb\col@sep
  \@tempdimc\col@sep
  \def\CT@color{%
    \global\let\CT@do@color\CT@@do@color
    \color}}
\def\CT@@do@color{%
  \global\let\CT@do@color\relax
        \@tempdima\wd\z@
        \advance\@tempdima\@tempdimb
        \advance\@tempdima\@tempdimc
        \kern-\@tempdimb
        \leaders\vrule
^^A                     \@height\p@\@depth\p@
                \hskip\@tempdima\@plus  1fill
        \kern-\@tempdimc
        \hskip-\wd\z@ \@plus -1fill }
\def\CT@extract#1\columncolor#2#3\@nil{%
  \if!#2%
    \let\CT@column@color\@empty
  \else
    \if[#2%
      \CT@extractb{#1}#3\@nil
    \else
      \def\CT@column@color{%
        \CT@color{#2}}%
      \CT@extractd{#1}#3\@nil
    \fi
  \fi}
\def\CT@extractb#1#2]#3{%
  \def\CT@column@color{%
    \CT@color[#2]{#3}}%
  \CT@extractd{#1}}%
\def\CT@extractd#1{\@testopt{\CT@extracte{#1}}\col@sep}
\def\CT@extracte#1[#2]{\@testopt{\CT@extractf{#1}[#2]}{#2}}
\def\CT@extractf#1[#2][#3]#4\columncolor#5\@nil{%
  \@tempdimb#2\relax
  \@tempdimc#3\relax
  \edef\CT@column@color{%
    \CT@column@color
    \@tempdimb\the\@tempdimb\@tempdimc\the\@tempdimc\relax}%
  \toks\@tempcnta{#1#4}}%
\let\CT@everycr\everycr
\newtoks\everycr
\CT@everycr{\noalign{\global\let\CT@row@color\relax}\the\everycr}
\def\CT@start{%
  \let\CT@arc@save\CT@arc@
  \let\CT@drsc@save\CT@drsc@
  \let\CT@row@color@save\CT@row@color
  \let\CT@cell@color@save\CT@cell@color
  \global\let\CT@cell@color\relax}
\def\CT@end{%
  \global\let\CT@arc@\CT@arc@save
  \global\let\CT@drsc@\CT@drsc@save
  \global\let\CT@row@color\CT@row@color@save
  \global\let\CT@cell@color\CT@cell@color@save}
\gdef\@ishortstack#1{%
  \CT@start\ialign{\mb@l {##}\unskip\mb@r\cr #1\crcr}\CT@end\egroup}
\AtBeginDocument{%
  \expandafter\def\expandafter\@tabarray\expandafter{%
    \expandafter\CT@start\@tabarray}}
\def\endarray{\crcr \egroup \egroup \gdef\@preamble{}\CT@end}
\long\def\multicolumn#1#2#3{%
   \multispan{#1}\begingroup
   \def\@addamp{\if@firstamp \@firstampfalse \else
                \@preamerr 5\fi}%
   \@mkpream{#2}\@addtopreamble\@empty
   \endgroup
   \def\@sharp{#3}%
   \let\CT@cell@color\relax
   \let\CT@column@color\relax
   \let\CT@do@color\relax
   \@arstrut \@preamble
   \null
   \ignorespaces}
\def\@classvi{\ifcase \@lastchclass
      \@acol \or
      \ifx\CT@drsc@\relax
        \@addtopreamble{\hskip\doublerulesep}%
      \else
        \@addtopreamble{{\CT@drsc@\vrule\@width\doublerulesep}}%
      \fi\or
      \@acol \or
      \@classvii
      \fi}
\def\doublerulesepcolor#1#{\CT@drs{#1}}
\def\CT@drs#1#2{%
 \ifdim\baselineskip=\z@\noalign\fi
  {\gdef\CT@drsc@{\color#1{#2}}}}
\let\CT@drsc@\relax
\def\arrayrulecolor#1#{\CT@arc{#1}}
\def\CT@arc#1#2{%
  \ifdim\baselineskip=\z@\noalign\fi
  {\gdef\CT@arc@{\color#1{#2}}}}
\let\CT@arc@\relax
\def\@arrayrule{\@addtopreamble {{\CT@arc@\vline}}}
\def\hline{%
  \noalign{\ifnum0=`}\fi
              \let\hskip\vskip
               \let\vrule\hrule
               \let\@width\@height
  {\CT@arc@\vline}%
  \futurelet
   \reserved@a\@xhline}
\def\@xhline{\ifx\reserved@a\hline
               {\ifx\CT@drsc@\relax
                  \vskip
               \else
                  \CT@drsc@\hrule\@height
               \fi
               \doublerulesep}%
             \fi
      \ifnum0=`{\fi}}
\def\@cline#1-#2\@nil{%
  \omit
  \@multicnt#1%
  \advance\@multispan\m@ne
  \ifnum\@multicnt=\@ne\@firstofone{&\omit}\fi
  \@multicnt#2%
  \advance\@multicnt-#1%
  \advance\@multispan\@ne
  {\CT@arc@\leaders\hrule\@height\arrayrulewidth\hfill}%
  \cr
  \noalign{\vskip-\arrayrulewidth}}
\newlength\minrowclearance
\minrowclearance=0pt
\expandafter\def\expandafter\@mkpream\expandafter#\expandafter1%
  \expandafter{%
    \expandafter\let\expandafter\CT@setup\expandafter\relax
    \expandafter\let\expandafter\CT@color\expandafter\relax
    \expandafter\let\expandafter\CT@do@color\expandafter\relax
    \expandafter\let\expandafter\color\expandafter\relax
    \expandafter\let\expandafter\CT@column@color\expandafter\relax
    \expandafter\let\expandafter\CT@row@color\expandafter\relax
    \expandafter\let\expandafter\CT@cell@color\expandafter\relax
    \@mkpream{#1}}
\let\CT@do@color\relax
\def\rowcolor{%
  \noalign{\ifnum0=`}\fi
  \global\let\CT@do@color\CT@@do@color
  \@ifnextchar[\CT@rowa\CT@rowb}
\def\CT@rowa[#1]#2{%
  \gdef\CT@row@color{\CT@color[#1]{#2}}%
  \CT@rowc}
\def\CT@rowb#1{%
  \gdef\CT@row@color{\CT@color{#1}}%
  \CT@rowc}
\def\CT@rowc{%
  \@ifnextchar[\CT@rowd{\ifnum`{=0\fi}}}
\def\CT@rowd[#1]{\@testopt{\CT@rowe[#1]}{#1}}
\def\CT@rowe[#1][#2]{%
  \@tempdimb#1%
  \@tempdimc#2%
  \xdef\CT@row@color{%
    \expandafter\noexpand\CT@row@color
    \@tempdimb\the\@tempdimb
    \@tempdimc\the\@tempdimc
    \relax}%
  \ifnum0=`{\fi}}
\edef\cellcolor{\noexpand\protect
  \expandafter\noexpand\csname cellcolor \endcsname}
\@namedef{cellcolor }{%
  \@ifnextchar[{\CT@cellc\@firstofone}{\CT@cellc\@gobble[]}%
}
\def\CT@cellc#1[#2]#3{%
  \expandafter\gdef\expandafter\CT@cell@color\expandafter{%
    \expandafter\CT@color#1{[#2]}{#3}%
    \global\let\CT@cell@color\relax
}}
\global\let\CT@cell@color\relax
\AtBeginDocument{%
  \def\@tempa{$\hfil\egroup\box\z@\box\tw@}%
  \ifx\@tempa\DC@endright
    \def\DC@endright{%
      $\hfil\egroup
    \ifx\DC@rl\bgroup
      \hskip\stretch{-.5}\box\z@\box\tw@\hskip\stretch{-.5}%
    \else
      \box\z@\box\tw@
    \fi}%
  \else
    \def\@tempa{$\hfil\egroup\hfill\box\z@\box\tw@}%
    \ifx\@tempa\DC@endright
      \def\DC@endright{%
        $\hfil\egroup%
        \hskip\stretch{.5}\box\z@\box\tw@\hskip\stretch{-.5}}%
    \fi
  \fi}
\AtBeginDocument{%
  \ifx\hhline\@undefined\else
\def\HH@box#1#2{\vbox{{%
  \ifx\CT@drsc@\relax\else
    \global\dimen\thr@@\tw@\arrayrulewidth
    \global\advance\dimen\thr@@\doublerulesep
    {\CT@drsc@
     \hrule \@height\dimen\thr@@
     \vskip-\dimen\thr@@}%
  \fi
  \CT@arc@
  \hrule \@height \arrayrulewidth \@width #1
  \vskip\doublerulesep
  \hrule \@height \arrayrulewidth \@width #2}}}
\def\HH@loop{%
  \ifx\@tempb`\def\next##1{\the\toks@\cr}\else\let\next\HH@let
  \ifx\@tempb|\if@tempswa
          \ifx\CT@drsc@\relax
           \HH@add{\hskip\doublerulesep}%
          \else
           \HH@add{{\CT@drsc@\vrule\@width\doublerulesep}}%
           \fi
          \fi\@tempswatrue
          \HH@add{{\CT@arc@\vline}}\else
  \ifx\@tempb:\if@tempswa
          \ifx\CT@drsc@\relax
           \HH@add{\hskip\doublerulesep}%
          \else
           \HH@add{{\CT@drsc@\vrule\@width\doublerulesep}}%
           \fi
              \fi\@tempswatrue
      \HH@add{\@tempc\HH@box\arrayrulewidth\arrayrulewidth\@tempc}\else
  \ifx\@tempb##\if@tempswa\HH@add{\hskip\doublerulesep}\fi\@tempswatrue
         \HH@add{{\CT@arc@\vline\copy\@ne\@tempc\vline}}\else
  \ifx\@tempb~\@tempswafalse
           \if@firstamp\@firstampfalse\else\HH@add{&\omit}\fi
              \ifx\CT@drsc@\relax
                \HH@add{\hfil}\else
                 \HH@add{{%
                   \CT@drsc@\leaders\hrule\@height\HH@height\hfil}}%
               \fi
                 \else
  \ifx\@tempb-\@tempswafalse
           \gdef\HH@height{\arrayrulewidth}%
           \if@firstamp\@firstampfalse\else\HH@add{&\omit}\fi
              \HH@add{{%
                \CT@arc@\leaders\hrule\@height\arrayrulewidth\hfil}}%
                           \else
  \ifx\@tempb=\@tempswafalse
       \gdef\HH@height{\dimen\thr@@}%
       \if@firstamp\@firstampfalse\else\HH@add{&\omit}\fi
       \HH@add
          {\rlap{\copy\@ne}\leaders\copy\@ne\hfil\llap{\copy\@ne}}\else
  \ifx\@tempb t\HH@add{%
    \def\HH@height{\dimen\thr@@}%
    \HH@box\doublerulesep\z@}\@tempswafalse\else
  \ifx\@tempb b\HH@add{%
    \def\HH@height{\dimen\thr@@}%
    \HH@box\z@\doublerulesep}\@tempswafalse\else
  \ifx\@tempb>\def\next##1##2{%
     \HH@add{%
      {\baselineskip\p@\relax
       ##2%
      \global\setbox\@ne\HH@box\doublerulesep\doublerulesep}}%
       \HH@let!}\else
  \PackageWarning{hhline}%
      {\meaning\@tempb\space ignored in \noexpand\hhline argument%
       \MessageBreak}%
  \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi
  \next}
\fi}
\AtBeginDocument{
  \ifx\longtable\@undefined\else
    \def\LT@@hline{%
      \ifx\LT@next\hline
        \global\let\LT@next\@gobble
        \ifx\CT@drsc@\relax
          \gdef\CT@LT@sep{%
            \noalign{\penalty-\@medpenalty\vskip\doublerulesep}}%
        \else
          \gdef\CT@LT@sep{%
            \multispan\LT@cols{%
              \CT@drsc@\leaders\hrule\@height\doublerulesep\hfill}\cr}%
        \fi
      \else
        \global\let\LT@next\empty
        \gdef\CT@LT@sep{%
          \noalign{\penalty-\@lowpenalty\vskip-\arrayrulewidth}}%
      \fi
      \ifnum0=`{\fi}%
      \multispan\LT@cols
       {\CT@arc@\leaders\hrule\@height\arrayrulewidth\hfill}\cr
      \CT@LT@sep
      \multispan\LT@cols
       {\CT@arc@\leaders\hrule\@height\arrayrulewidth\hfill}\cr
      \noalign{\penalty\@M}%
      \LT@next}
    \fi}
\endinput
%%
%% End of file `colortbl.sty'.

Answer 2

The core issue in array.sty is due to some code missing for the \multicolumn case and needs some extra code there. The suggested fix for colortbl in David's answer as not quite complete and need also some further lines. Both are discussed in https://github.com/latex3/latex2e/issues/42 and a fixed version should come up in a couple of days.