LaTeX: partially fix color issues for wrapped code lines with pagebreak

This does not fix entirely sphinx-doc#10610 but it does sufficiently for it not to
require reverting sphinx-doc#10577 which tried to solve sphinx-doc#8686 conundrum.  In
extreme cases, the sphinx-doc#8686 problem meant that some contents disappeared
at page bottom, so it is probably better to maintain sphinx-doc#10577 which
will avoid any such overflow of code beyond its frame, even though in
some specific cases (a colored entity such as a long string is partly on
both pages), some syntax highlighting gets lost.

There are anyhow other issues with colors for wrapped code lines, even
with no pagebreaks involved, such as sphinx-doc#10615.  This patch does not change
the situation there.

sphinx/texinputs/sphinxlatexliterals.sty

@@ -1,7 +1,7 @@
 %% LITERAL BLOCKS
 %
 % change this info string if making any custom modification
-\ProvidesFile{sphinxlatexliterals.sty}[2022/06/18 code-blocks and parsed literals]
+\ProvidesFile{sphinxlatexliterals.sty}[2022/06/29 code-blocks and parsed literals]
 
 % Provides support for this output mark-up from Sphinx latex writer:
 %
@@ -99,37 +99,48 @@
 %  - frame is \fboxsep separated from the contents,
 %  - the contents use the full available text width,
 %  - #1 = color of frame, #2 = color of background,
-%  - #3 = above frame, #4 = below frame, #5 = within frame,
-%  - #3 and #4 must be already typeset boxes; they must issue \normalcolor
-%    or similar, else, they are under scope of color #1
+%  - #3 = will be typeset above frame,
+%  - #4 = will be typeset below frame,
+%  - #5 = will be typeset within frame,
+% #3 and #4 must be already typeset boxes.
+% #5 are the contents, and in the context of usage of fancyvrb+framed by
+% Sphinx, it will arrive here already transformed into horizontal
+% boxes.  The \normalcolor is a preventive measure to some color issues
+% when a pagebreak occurs in the middle of a wrapped long code line.
 \long\def\spx@fcolorbox #1#2#3#4#5{%
   \hskip\@totalleftmargin
   \hskip-\fboxsep\hskip-\fboxrule
   % MEMO: \color@b@x from xcolor.sty is identical with the one from color.sty
-  \color@b@x {\color{#1}\spx@CustomFBox{#3}{#4}}{\color{#2}}{#5}%
+  \color@b@x {\spx@CustomFBox{#1}{#3}{#4}}{\color{#2}}{{\normalcolor#5}}%
   \hskip-\fboxsep\hskip-\fboxrule
   \hskip-\linewidth \hskip-\@totalleftmargin \hskip\columnwidth
 }%
-% #1 = for material above frame, such as a caption or a "continued" hint
-% #2 = for material below frame, such as a caption or "continues on next page"
-% #3 = actual contents, which will be typeset with a background color
-\long\def\spx@CustomFBox#1#2#3{%
+% #1 = color of frame
+% #2 = for material above frame, such as a caption or a "continued" hint
+% #3 = for material below frame, such as a caption or "continues on next page"
+% #4 = contents; or rather if called from \spx@fcolorbox (only use case here),
+%      the contents are in \box\z@ and #4 is
+%      \color{<bgcolor>}\color@block {\wd \z@ }{\ht \z@ }{\dp \z@ }\box \z@
+\long\def\spx@CustomFBox#1#2#3#4{%
   \begingroup
-  \setbox\@tempboxa\hbox{{#3}}% inner braces to avoid color leaks
-  \vbox{#1% above frame
+  \setbox\@tempboxa\hbox{{#4}}% inner braces to avoid background color leak
+  \vbox{#2% above frame
             % draw frame border _latest_ to avoid pdf viewer issue
             \kern\fboxrule
             \hbox{\kern\fboxrule
                   \copy\@tempboxa
+                  {\color{#1}% frame color
                   \kern-\wd\@tempboxa\kern-\fboxrule
                   \vrule\@width\fboxrule
                   \kern\wd\@tempboxa
                   \vrule\@width\fboxrule}%
+                 }%
+            {\color{#1}% frame color
             \kern-\dimexpr\ht\@tempboxa+\dp\@tempboxa+\fboxrule\relax
             \hrule\@height\fboxrule
             \kern\dimexpr\ht\@tempboxa+\dp\@tempboxa\relax
-            \hrule\@height\fboxrule
-        #2% below frame
+            \hrule\@height\fboxrule}%
+        #3% below frame
        }%
   \endgroup
 }%
@@ -145,10 +156,10 @@
 %
 \def\sphinxVerbatim@Continued
    {\csname spx@fcolorbox@put@\spx@opt@verbatimcontinuedalign\endcsname
-    {\normalcolor\sphinxstylecodecontinued\literalblockcontinuedname}}%
+    {{\normalcolor\sphinxstylecodecontinued\literalblockcontinuedname}}}%
 \def\sphinxVerbatim@Continues
    {\csname spx@fcolorbox@put@\spx@opt@verbatimcontinuesalign\endcsname
-    {\normalcolor\sphinxstylecodecontinues\literalblockcontinuesname}}%
+    {{\normalcolor\sphinxstylecodecontinues\literalblockcontinuesname}}}%
 \def\sphinxVerbatim@Title
    {\spx@fcolorbox@put@c{\unhcopy\sphinxVerbatim@TitleBox}}%
 \let\sphinxVerbatim@Before\@empty

sphinx/texinputs/sphinxlatexstyletext.sty

@@ -1,7 +1,7 @@
 %% TEXT STYLING
 %
 % change this info string if making any custom modification
-\ProvidesFile{sphinxlatexstyletext.sty}[2021/12/06 text styling]
+\ProvidesFile{sphinxlatexstyletext.sty}[2022/06/29 text styling]
 
 % Basically everything here consists of macros which are part of the latex
 % markup produced by the Sphinx latex writer
@@ -39,15 +39,16 @@
 \protected\def\sphinxstyleothertitle   #1{\textbf{#1}}
 \protected\def\sphinxstylesidebarsubtitle #1{~\\\textbf{#1} \smallskip}
 % \text.. commands do not allow multiple paragraphs
+% attention, this one is not self-delimiting
 \protected\def\sphinxstyletheadfamily    {\sffamily}
 \protected\def\sphinxstyleemphasis     #1{\emph{#1}}
 \protected\def\sphinxstyleliteralemphasis#1{\emph{\sphinxcode{#1}}}
 \protected\def\sphinxstylestrong       #1{\textbf{#1}}
 \protected\def\sphinxstyleliteralstrong#1{\sphinxbfcode{#1}}
 \protected\def\sphinxstyleabbreviation #1{\textsc{#1}}
 \protected\def\sphinxstyleliteralintitle#1{\sphinxcode{#1}}
-\newcommand*\sphinxstylecodecontinued[1]{\footnotesize(#1)}%
-\newcommand*\sphinxstylecodecontinues[1]{\footnotesize(#1)}%
+\newcommand*\sphinxstylecodecontinued[1]{{\footnotesize(#1)}}%
+\newcommand*\sphinxstylecodecontinues[1]{{\footnotesize(#1)}}%
 % figure legend comes after caption and may contain arbitrary body elements
 \newenvironment{sphinxlegend}{\par\small}{\par}
 % reduce hyperref "Token not allowed in a PDF string" warnings on PDF builds