Longtabu, \tabucline placed on wrong page

Question

See the following longtabu axample:

\documentclass{article}

\usepackage{longtable}
\usepackage{booktabs}
\usepackage{tabu}

\usepackage{lipsum}

\begin{document}

\tabulinesep=1.5mm    % <---- seems like this is causing the issue

\def\head{Head A & Head B}
\def\nbcolumns{2}
\begin{longtabu}{X[.5,l] X[1,l]}
  \toprule\rowfont{\bfseries}
  \head\\
  \midrule
  \endfirsthead
%
  \multicolumn{\nbcolumns}{l}{\scriptsize\itshape\ldots Fortsetzung}\\
  \toprule\rowfont{\bfseries}
  \head\\
  \midrule
  \endhead
%
  \multicolumn{\nbcolumns}{r}{\scriptsize\itshape wird fortgesetzt \ldots}
  \endfoot
  \endlastfoot
%
  \everyrow{\tabucline[on 3 pt off 3pt]-}
  1 & \lipsum[2] \\
  2 & \lipsum[2] \\
  3 & \lipsum[2] \\
  4 & \lipsum[2] \\
  5 & \lipsum[2] \\
  6 & \lipsum[2] \\
  7 & \lipsum[2] \\
  8 & \lipsum[2] 
  \everyrow{}\\
  \bottomrule
  \caption{Table name}
\end{longtabu}

\end{document}

... and the resulting document:

The page break from page 1 to page 2 is as expected.

But there is an issue with the page break from page 2 to page 3. The first dashed line on the top of page 3 should be placed on the bottom of page 2.

How can I fix it?

Or should I consider using an alternative to longtabu?

Answer 1

You can add a \nobreak so linebreaking before the tabu cline is discouraged and add a \filbreak so linebreaking (and padding with space) after the line is encouraged.

\documentclass{article}

\usepackage{longtable}
\usepackage{booktabs}
\usepackage{tabu}

\makeatletter
\renewcommand*\tabucline{\noalign{\nobreak\ifnum0=`}\fi \tabu@cline}


\def\tabu@docline@evr {\xdef\tabu@doclineafter{\the\toks@\filbreak}%
              \ifnum0=`{\fi}\aftergroup\tabu@doclineafter}

\makeatother

\usepackage{lipsum}

\begin{document}

\tabulinesep=1.5mm    % <---- seems like this is causing the issue

\def\head{Head A & Head B}
\def\nbcolumns{2}
\begin{longtabu}{X[.5,l] X[1,l]}
  \toprule\rowfont{\bfseries}
  \head\\
  \midrule
  \endfirsthead
%
  \multicolumn{\nbcolumns}{l}{\scriptsize\itshape\ldots Fortsetzung}\\
  \toprule\rowfont{\bfseries}
  \head\\
  \midrule
  \endhead
%
  \multicolumn{\nbcolumns}{r}{\scriptsize\itshape wird fortgesetzt \ldots}
  \endfoot
  \endlastfoot
%
  \everyrow{\tabucline[on 3 pt off 3pt]-}
  1 & \lipsum[2] \\
  2 & \lipsum[2] \\
  3 & \lipsum[2] \\
  4 & \lipsum[2] \\
  5 & \lipsum[2] \\
  6 & \lipsum[2] \\
  7 & \lipsum[2] \\
  8 & \lipsum[2]
  \everyrow{}\\*
  \bottomrule
  \caption{Table name}
\end{longtabu}

\end{document}