Background colour and vlines are non-existent for negative rowsep

[Aljumaily]

I understand that having a negative rowsep makes the row height smaller than anticipated and the output is expected. I want a way to show the background colour and the vlines for rows that are tightest in row height. Having rowsep=0pt is not the tightest.

\documentclass{article}
\usepackage{xcolor}
\usepackage{tabularray}
\begin{document}

\begin{tblr}{rowsep=0pt, vlines, hlines, row{odd}={azure9}, row{even}={gray8}}
    Alpha   & Beta  & Gamma  & Delta \\
    Epsilon & Zeta  & Eta    & Theta \\
    Iota    & Kappa & Lambda & Mu    \\
\end{tblr}
\par\vspace{2em}
\begin{tblr}{rowsep=-10pt, vlines, hlines, row{odd}={azure9}, row{even}={gray8}}
    Alpha   & Beta  & Gamma  & Delta \\
    Epsilon & Zeta  & Eta    & Theta \\
    Iota    & Kappa & Lambda & Mu    \\
\end{tblr}
\end{document}

[muzimuzhi]

I want a way to show the background colour and the vlines for rows that are tightest in row height.

rowsep=0pt, stretch=0

\documentclass{article}
\usepackage{xcolor}
\usepackage{tabularray}
\begin{document}

\begin{tblr}{rowsep=0pt, vlines, hlines, row{odd}={azure9}, row{even}={gray8}}
    Alpha   & Beta  & Gamma  & Delta \\
    Epsilon & Zeta  & Eta    & Theta \\
    Iota    & Kappa & Lambda & Mu    \\
\end{tblr}
\par\vspace{2em}
\begin{tblr}{rowsep=0pt, stretch=0, vlines, hlines, row{odd}={azure9}, row{even}={gray8}}
    Alpha   & Beta  & Gamma  & Delta \\
    Epsilon & Zeta  & Eta    & Theta \\
    Iota    & Kappa & Lambda & Mu    \\
\end{tblr}
\end{document}

[muzimuzhi]

About negative rowsep, I'm guessing it's caused by a negative depth and/or lower part of a row obtained by some internal calculation step.

\documentclass{article}
\usepackage{xcolor}
\usepackage{tabularray}

\begin{document}
\def\testRowsep#1{%
  \leavevmode\llap{\small\texttt{\detokenize{#1}}}
  \begin{tblr}{vlines, hlines, row{odd}={azure9}, row{even}={gray8}, baseline=T, #1}
    Alpha   & Beta  & Gamma  & Delta \\
    Epsilon & Zeta  & Eta    & Theta \\
    Iota    & Kappa & Lambda & Mu    \\
  \end{tblr}
  \par\medskip
}

\testRowsep{rowsep= 0pt}
\testRowsep{rowsep=-3pt}
\testRowsep{rowsep=-5pt}
\testRowsep{rowsep=-10pt}
\end{document}

[Aljumaily]

Thank you! Resolved my issue.

[muzimuzhi]

The interaction of negative rowsep and background color seems problematic, so let's keep this issue open until this is resolved.