PDF output of tables using `multirow` too wide

Bug description

When using pandas to create tables with a multi-index, Quarto uses the \multirow LaTeX command to display that in the PDF. However, the resulting columns are far too wide.

I think the reason is that the LaTeX code contains multirow commands that look like this: \multirow{2}{=}{foo}, because when I use \multirow{2}*{foo}, then the table looks nice.

Steps to reproduce

With an installation of Python 3.10 and pandas 2.2.1, compile the below document to PDF via quarto render test.qmd --to pdf. The command runs without any errors or warnings.

---
title: "Test Title"
authors:
  - name: Testing Tester
format:
  html:
    code-fold: true
  pdf:
    keep-tex: true
    include-in-header:
    - text: |
        \usepackage{multirow}
jupyter: python3
execute: 
  cache: true
---

# Table Test

```{python}
#| echo: false
#| label: tbl-contra
#| tbl-cap: This table is far too wide for its content.

import pandas as pd
import numpy as np

data = pd.DataFrame({
  'a': np.random.uniform(size=8),
  'b': 100 * np.random.uniform(size=8),
  'c': np.random.randint(low=0, high=1000, size=8),
})
idx = pd.MultiIndex.from_product([['x', 'y'], ['foo', 'bar'], ['1', '2']])
data.index = idx

data.style \
  .format(precision=2)
```

In my case, because I set keep-tex: true, I get an intermediate LaTeX file, which looks like this:

% Options for packages loaded elsewhere
\PassOptionsToPackage{unicode}{hyperref}
\PassOptionsToPackage{hyphens}{url}
\PassOptionsToPackage{dvipsnames,svgnames,x11names}{xcolor}
%
\documentclass[
  letterpaper,
  DIV=11,
  numbers=noendperiod]{scrartcl}

\usepackage{amsmath,amssymb}
\usepackage{iftex}
\ifPDFTeX
  \usepackage[T1]{fontenc}
  \usepackage[utf8]{inputenc}
  \usepackage{textcomp} % provide euro and other symbols
\else % if luatex or xetex
  \usepackage{unicode-math}
  \defaultfontfeatures{Scale=MatchLowercase}
  \defaultfontfeatures[\rmfamily]{Ligatures=TeX,Scale=1}
\fi
\usepackage{lmodern}
\ifPDFTeX\else  
    % xetex/luatex font selection
\fi
% Use upquote if available, for straight quotes in verbatim environments
\IfFileExists{upquote.sty}{\usepackage{upquote}}{}
\IfFileExists{microtype.sty}{% use microtype if available
  \usepackage[]{microtype}
  \UseMicrotypeSet[protrusion]{basicmath} % disable protrusion for tt fonts
}{}
\makeatletter
\@ifundefined{KOMAClassName}{% if non-KOMA class
  \IfFileExists{parskip.sty}{%
    \usepackage{parskip}
  }{% else
    \setlength{\parindent}{0pt}
    \setlength{\parskip}{6pt plus 2pt minus 1pt}}
}{% if KOMA class
  \KOMAoptions{parskip=half}}
\makeatother
\usepackage{xcolor}
\setlength{\emergencystretch}{3em} % prevent overfull lines
\setcounter{secnumdepth}{-\maxdimen} % remove section numbering
% Make \paragraph and \subparagraph free-standing
\ifx\paragraph\undefined\else
  \let\oldparagraph\paragraph
  \renewcommand{\paragraph}[1]{\oldparagraph{#1}\mbox{}}
\fi
\ifx\subparagraph\undefined\else
  \let\oldsubparagraph\subparagraph
  \renewcommand{\subparagraph}[1]{\oldsubparagraph{#1}\mbox{}}
\fi


\providecommand{\tightlist}{%
  \setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}\usepackage{longtable,booktabs,array}
\usepackage{calc} % for calculating minipage widths
% Correct order of tables after \paragraph or \subparagraph
\usepackage{etoolbox}
\makeatletter
\patchcmd\longtable{\par}{\if@noskipsec\mbox{}\fi\par}{}{}
\makeatother
% Allow footnotes in longtable head/foot
\IfFileExists{footnotehyper.sty}{\usepackage{footnotehyper}}{\usepackage{footnote}}
\makesavenoteenv{longtable}
\usepackage{graphicx}
\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth\else\Gin@nat@width\fi}
\def\maxheight{\ifdim\Gin@nat@height>\textheight\textheight\else\Gin@nat@height\fi}
\makeatother
% Scale images if necessary, so that they will not overflow the page
% margins by default, and it is still possible to overwrite the defaults
% using explicit options in \includegraphics[width, height, ...]{}
\setkeys{Gin}{width=\maxwidth,height=\maxheight,keepaspectratio}
% Set default figure placement to htbp
\makeatletter
\def\fps@figure{htbp}
\makeatother

\usepackage{multirow}
\KOMAoption{captions}{tableheading}
\makeatletter
\@ifpackageloaded{caption}{}{\usepackage{caption}}
\AtBeginDocument{%
\ifdefined\contentsname
  \renewcommand*\contentsname{Table of contents}
\else
  \newcommand\contentsname{Table of contents}
\fi
\ifdefined\listfigurename
  \renewcommand*\listfigurename{List of Figures}
\else
  \newcommand\listfigurename{List of Figures}
\fi
\ifdefined\listtablename
  \renewcommand*\listtablename{List of Tables}
\else
  \newcommand\listtablename{List of Tables}
\fi
\ifdefined\figurename
  \renewcommand*\figurename{Figure}
\else
  \newcommand\figurename{Figure}
\fi
\ifdefined\tablename
  \renewcommand*\tablename{Table}
\else
  \newcommand\tablename{Table}
\fi
}
\@ifpackageloaded{float}{}{\usepackage{float}}
\floatstyle{ruled}
\@ifundefined{c@chapter}{\newfloat{codelisting}{h}{lop}}{\newfloat{codelisting}{h}{lop}[chapter]}
\floatname{codelisting}{Listing}
\newcommand*\listoflistings{\listof{codelisting}{List of Listings}}
\makeatother
\makeatletter
\makeatother
\makeatletter
\@ifpackageloaded{caption}{}{\usepackage{caption}}
\@ifpackageloaded{subcaption}{}{\usepackage{subcaption}}
\makeatother
\ifLuaTeX
  \usepackage{selnolig}  % disable illegal ligatures
\fi
\usepackage{bookmark}

\IfFileExists{xurl.sty}{\usepackage{xurl}}{} % add URL line breaks if available
\urlstyle{same} % disable monospaced font for URLs
\hypersetup{
  pdftitle={Test Title},
  colorlinks=true,
  linkcolor={blue},
  filecolor={Maroon},
  citecolor={Blue},
  urlcolor={Blue},
  pdfcreator={LaTeX via pandoc}}

\title{Test Title}
\author{Testing Tester}
\date{}

\begin{document}
\maketitle

\section{Table Test}\label{table-test}

\begin{longtable}[]{@{}llllll@{}}

\caption{\label{tbl-contra}This table is far too wide for its content.}

\tabularnewline

\caption{}\label{T_331e1}\tabularnewline
\toprule\noalign{}
~ & ~ & ~ & a & b & c \\
\midrule\noalign{}
\endfirsthead
\toprule\noalign{}
~ & ~ & ~ & a & b & c \\
\midrule\noalign{}
\endhead
\bottomrule\noalign{}
\endlastfoot
\multirow{4}{=}{x} & \multirow{2}{=}{foo} & 1 & 0.50 & 39.44 & 817 \\
& & 2 & 0.44 & 34.31 & 655 \\
& \multirow{2}{=}{bar} & 1 & 0.47 & 72.27 & 454 \\
& & 2 & 0.40 & 87.38 & 332 \\
\multirow{4}{=}{y} & \multirow{2}{=}{foo} & 1 & 0.24 & 28.72 & 254 \\
& & 2 & 0.20 & 89.23 & 599 \\
& \multirow{2}{=}{bar} & 1 & 0.03 & 26.64 & 619 \\
& & 2 & 0.52 & 10.13 & 323 \\

\end{longtable}

\end{document}

Expected behavior

The table should fit on the page, as in this screenshot:

Actual behavior

All columns are stretched wide and the table extends beyond the right side of the page. See this screenshot:

Your environment

• IDE: VS Code v1.87.1
• OS: Ubuntu 22.04 inside WSL2 on Windows 11

Quarto check output

Quarto 1.5.24
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.11: OK
      Dart Sass version 1.70.0: OK
      Deno version 1.41.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.5.24
      Path: /opt/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: v2024.03
      Chromium: (not installed)

[✓] Checking LaTeX....................OK
      Using: TinyTex
      Path: /home/rmnldwg/.TinyTeX/bin/x86_64-linux
      Version: 2023

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.10.12
      Path: /home/rmnldwg/repos/test/.venv/bin/python3
      Jupyter: 5.7.1
      Kernels: python3

[✓] Checking Jupyter engine render....OK

[✓] Checking R installation...........(None)

      Unable to locate an installed version of R.
      Install R from https://cloud.r-project.org/

Start by rendering the supplied test.qmd with quarto render test.qmd --to pdf and inspect the intermediate LaTeX produced with keep-tex: true, focusing on the generated multirow commands. Done means the reproduced multi-index table fits the page without stretched columns and retains the expected PDF layout.