use everypar for strut in \LT@startpbox, issue #1128

base/doc/ltnews38.tex

@@ -174,8 +174,10 @@ \section{Changes to packages in the \pkg{amsmath} category}
 \section{Changes to packages in the \pkg{graphics} category}
 
 \section{Changes to packages in the \pkg{tools} category}
+\subsection{\pkg{longtable}: correct p-column definition}
 
-
+In general the \pkg{longtable} implementation follows 
+the \pkg{array} usage but the package didn't take over a change made 1992 in \pkg{array} which adjusted the handling of the strut inserted at the begin of p-columns. As a consequence there are a number of inconsistencies in the output of p-columns between \pkg{tabular} and \pkg{longtable}. This has been corrected, \pkg{longtable} uses now for the strut the same definition as \pkg{array}. \githubissue{1128}
 %\medskip
 
 \begin{thebibliography}{9}

required/tools/changes.txt

@@ -9,6 +9,11 @@ are not part of the distribution.
 All changes above are only part of the development branch for the next release.
 ================================================================================
 
+2023-08-25  Ulrike Fischer  <Ulrike.Fischer@latex-project.org>
+
+	* longtable.dtx: use \everypar to insert the strut in \LT@startpbox 
+      to match the array use, github/1128 
+
 #########################
 # 2023-06-01 Release
 #########################

required/tools/longtable.dtx

@@ -37,7 +37,7 @@
 %<driver> \ProvidesFile{longtable.drv}
 % \fi
 %         \ProvidesFile{longtable.dtx}
-          [2021-09-01 v4.17 Multi-page Table package (DPC)]
+          [2025-08-25 v4.18 Multi-page Table package (DPC)]
 %
 % \iffalse
 %<*driver>
@@ -2206,12 +2206,16 @@
   \bgroup
 %    \end{macrocode}
 % \changes{v4.12}{2019/02/06}{Color group to match array package}
+% \changes{v4.18}{2023/08/25}{Use \cs{everypar} to match array package, github 1128}% 
 %    \begin{macrocode}
     \color@begingroup
     \let\@footnotetext\LT@p@ftntext
     \setlength\hsize{#1}%
     \@arrayparboxrestore
-    \vrule \@height \ht\@arstrutbox \@width \z@}
+    \everypar{%
+      \vrule \@height \ht\@arstrutbox \@width \z@
+      \everypar{}}%    
+    }
 %    \end{macrocode}
 % \end{macro}
 %

required/tools/testfiles/github-1128.lvt

@@ -0,0 +1,16 @@
+\documentclass{article}
+\input{regression-test}
+\usepackage{longtable,array}
+\begin{document}
+\START \showoutput
+\begin{tabular}{lp{1cm}}
+\hline 
+some text & \medskip xxx
+\end{tabular}
+
+\begin{longtable}{lp{1cm}}
+\hline 
+some text & \medskip xxx
+\end{longtable}
+
+\end{document} 

required/tools/testfiles/github-1128.tlg

@@ -0,0 +1,146 @@
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+Don't change this file in any respect.
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