LaTeX: Inhibit breaks for rows with merged vertical cells

This inhibits breaking in rows with vertically merged cells per stack
exchange [1].  Tested against longtable.

[1] https://tex.stackexchange.com/questions/52100/%20longtable-multirow-problem-with-cline-and-nopagebreak#answer-52101

Author: tim-nordell-nimbelink

CHANGES.rst

@@ -35,6 +35,8 @@ Bugs fixed
   Patch by Günter Milde
 * LaTeX: Fix rendering for grid filled merged vertical cell.
   Patch by Tim Nordell
+* LaTeX: Fix overrun footer for certain cases of merged vertical table cells.
+  Patch by Tim Nordell
 * #14207: Fix creating ``HTMLThemeFactory`` objects in third-party extensions.
   Patch by Adam Turner
 * #3099: LaTeX: PDF build crashes if a code-block contains more than

sphinx/texinputs/sphinxlatextables.sty

@@ -776,7 +776,7 @@
   \leaders\hrule\@height\arrayrulewidth\hfill}%
   \cr
 % the last one will need to be compensated, this is job of \sphinxclines
-  \noalign{\vskip-\arrayrulewidth}%
+  \noalign{\nobreak\vskip-\arrayrulewidth}%
 }
 \def\spx@table@fixvlinejoin{%
   {\CT@arc@ % this is the color command set up by \arrayrulecolor
@@ -800,7 +800,7 @@
   \hfill
   \spx@table@fixvlinejoin
   \cr
-  \noalign{\vskip-\arrayrulewidth}%
+  \noalign{\nobreak\vskip-\arrayrulewidth}%
 }
 % This "fixclines" is also needed if no \sphinxcline emitted and is useful
 % even in extreme case with no \sphinxvlinecrossing either, to give correct
@@ -819,6 +819,7 @@
   \spx@table@fixvlinejoin% fill small gap at right-bordered table
   \cr
   % this final one does NO \vskip-\arrayrulewidth... that's the whole point
+  \noalign{\nobreak}%
 }
 %%%% end of \cline workarounds
 

sphinx/writers/latex.py

@@ -1307,15 +1307,16 @@ def visit_row(self, node: Element) -> None:
 
     def depart_row(self, node: Element) -> None:
         assert self.table is not None
-        self.body.append(r'\\' + CR)
         cells = [self.table.cell(self.table.row, i) for i in range(self.table.colcount)]
         underlined = [
             cell.row + cell.height == self.table.row + 1  # type: ignore[union-attr]
             for cell in cells
         ]
         if all(underlined):
+            self.body.append(r'\\' + CR)
             self.body.append(r'\sphinxhline')
         else:
+            self.body.append(r'\\*' + CR)
             i = 0
             underlined.extend([False])  # sentinel
             if underlined[0] is False:

tests/roots/test-latex-table/expects/complex_spanning_cell.tex

@@ -52,15 +52,15 @@
 \sphinxbeforeendvarwidth
 \end{varwidth}%
 }%
-\\
+\\*
 \sphinxvlinecrossing{1}\sphinxcline{3-3}\sphinxvlinecrossing{4}\sphinxfixclines{5}\sphinxtablestrut{1}&\sphinxtablestrut{2}&\sphinxmultirow{2}{6}{%
 \begin{varwidth}[t]{\sphinxcolwidth{1}{5}}
 \sphinxAtStartPar
 cell2\sphinxhyphen{}3
 \sphinxbeforeendvarwidth
 \end{varwidth}%
 }%
-&\sphinxtablestrut{4}&\sphinxtablestrut{5}\\
+&\sphinxtablestrut{4}&\sphinxtablestrut{5}\\*
 \sphinxvlinecrossing{1}\sphinxvlinecrossing{2}\sphinxvlinecrossing{3}\sphinxcline{5-5}\sphinxfixclines{5}\sphinxtablestrut{1}&\sphinxtablestrut{2}&\sphinxtablestrut{6}&\sphinxtablestrut{4}&\begin{varwidth}[t]{\sphinxcolwidth{1}{5}}
 \sphinxAtStartPar
 cell3\sphinxhyphen{}5

tests/roots/test-latex-table/expects/grid_table.tex

@@ -40,7 +40,7 @@
 cell1\sphinxhyphen{}3
 \sphinxbeforeendvarwidth
 \end{varwidth}%
-\\
+\\*
 \sphinxcline{1-1}\sphinxcline{3-3}\sphinxfixclines{3}\sphinxmultirow{2}{7}{%
 \begin{varwidth}[t]{\sphinxcolwidth{1}{3}}
 \sphinxAtStartPar
@@ -53,7 +53,7 @@
 cell2\sphinxhyphen{}3
 \sphinxbeforeendvarwidth
 \end{varwidth}%
-\\
+\\*
 \sphinxcline{2-3}\sphinxfixclines{3}\sphinxtablestrut{7}&\sphinxstartmulticolumn{2}%
 \sphinxmultirow{2}{9}{%
 \begin{varwidth}[t]{\sphinxcolwidth{2}{3}}
@@ -66,7 +66,7 @@
 \end{varwidth}%
 }%
 \sphinxstopmulticolumn
-\\
+\\*
 \sphinxcline{1-1}\sphinxfixclines{3}\begin{varwidth}[t]{\sphinxcolwidth{1}{3}}
 \sphinxAtStartPar
 cell4\sphinxhyphen{}1

tests/roots/test-latex-table/expects/grid_table_with_tabularcolumns.tex

@@ -40,7 +40,7 @@
 cell1\sphinxhyphen{}3
 \sphinxbeforeendvarwidth
 \end{varwidth}%
-\\
+\\*
 \sphinxcline{1-1}\sphinxcline{3-3}\sphinxfixclines{3}\sphinxmultirow{2}{7}{%
 \begin{varwidth}[t]{\sphinxcolwidth{1}{3}}
 \sphinxAtStartPar
@@ -53,7 +53,7 @@
 cell2\sphinxhyphen{}3
 \sphinxbeforeendvarwidth
 \end{varwidth}%
-\\
+\\*
 \sphinxcline{2-3}\sphinxfixclines{3}\sphinxtablestrut{7}&\sphinxstartmulticolumn{2}%
 \sphinxmultirow{2}{9}{%
 \begin{varwidth}[t]{\sphinxcolwidth{2}{3}}
@@ -66,7 +66,7 @@
 \end{varwidth}%
 }%
 \sphinxstopmulticolumn
-\\
+\\*
 \sphinxcline{1-1}\sphinxfixclines{3}\begin{varwidth}[t]{\sphinxcolwidth{1}{3}}
 \sphinxAtStartPar
 cell4\sphinxhyphen{}1