Wrong line width in long table

[hvoss49]

I used longtable and booktabs. For some reason I wanted only normal lines instead of the\toprule etc commands. I used

\let\toprule\hline
\let\midrule\hline
\let\bottomrule\hline

for a short test. The lines of the first and last column now filled the complete text width. Is this the intended behaviour with up-to-date TL2024?

\documentclass{article}

\usepackage{longtable}
%\usepackage{booktabs}

\let\toprule\hline
\let\midrule\hline
\let\bottomrule\hline

\begin{document}

\begin{longtable}{l|c|r} 
\caption{Multipage table.}\label{tab:table1}\\\toprule 
\emph{Value 1} & {\emph{Value 2}} & \emph{Value 3}\\
$\alpha$ & $\beta$ & {$\gamma$} \\\midrule
\endfirsthead                 
\toprule
\emph{Value 1} & {\emph{Value 2}} & \emph{Value 3}\\
$\alpha$ & $\beta$ & {$\gamma$} \\\midrule
\endhead                      
\midrule 
\multicolumn{3}{r}{Fortsetzung $\rightarrow$}\\ 
\endfoot 
\bottomrule
\endlastfoot 
1 & 1110.1 & a\\  2 & 10.1 & b\\  3 & 23.113231 & c\\  1 & 1110.1 & a\\  2 & 
10.1 & b\\  3 & 23.113231 & c\\
1 & 1110.1 & a\\  2 & 10.1 & b\\  3 & 23.113231 & c\\  1 & 1110.1 & a\\  2 & 
10.1 & b\\  3 & 23.113231 & c\\
\end{longtable}

Changing all to \hline instead of the \let commands works fine.

[davidcarlisle]

that can't work: you are defining the booktabs commands to be the versions for tabular not longtable. you would need to use \def (or \renewcommand) not \let so that they expanded to the definition of \hline current at that point.