CTAN sync 202101010304

1 files changed, 17 insertions, 5 deletions

diff --git a/macros/latex/base/ltshipout.dtx b/macros/latex/base/ltshipout.dtx
index 8f0422c887..e226f753f3 100644
--- a/macros/latex/base/ltshipout.dtx
+++ b/macros/latex/base/ltshipout.dtx
@@ -31,8 +31,8 @@
 %%% From File: ltshipout.dtx
 %
 %    \begin{macrocode}
-\providecommand\ltshipoutversion{v1.0c}
-\providecommand\ltshipoutdate{2020/09/27}
+\providecommand\ltshipoutversion{v1.0d}
+\providecommand\ltshipoutdate{2020/11/24}
 %    \end{macrocode}
 %
 %<*driver>
@@ -1376,9 +1376,11 @@
 %
 %
 %  \begin{macro}{\AtBeginDvi}
-%    
+%    If we roll forward from an earlier kernel \cs{AtBeginDvi} is
+%    defined so we better not use \cs{cs_new_protected:Npn} here.
+% \changes{v1.0d}{2020/11/24}{Support for roll forward (gh/434)}
 %    \begin{macrocode}
-\cs_new_protected:Npn \AtBeginDvi {\@@_add_firstpage_material:Nn \AtBeginDvi}
+\cs_set_protected:Npn \AtBeginDvi {\@@_add_firstpage_material:Nn \AtBeginDvi}
 %    \end{macrocode}
 %  \end{macro}
 %
@@ -1448,7 +1450,17 @@
 %    \begin{macrocode}
 %<latexrelease>\IncludeInRelease{0000/00/00}%
 %<latexrelease>                 {\shipout}{The hook management (shipout)}%
-%<latexrelease>\expandafter\let\expandafter\shipout\csname tex_shipout:D\endcsname
+%<latexrelease>
+%    \end{macrocode}
+%    If we roll forward then \cs{tex\_shipout:D} may not be defined in
+%    which case \cs{shipout} does have it original definition and so
+%    we must not \cs{let} it to something else which is \cs{relax}! 
+% \changes{v1.0d}{2020/11/24}{Support for roll forward (gh/434)}
+%    \begin{macrocode}
+%<latexrelease>\ifcsname tex_shipout:D\endcsname
+%<latexrelease>\expandafter\let\expandafter\shipout
+%<latexrelease>                \csname tex_shipout:D\endcsname
+%<latexrelease>\fi
 %<latexrelease>
 %<latexrelease>\let \ShipoutBox\@undefined
 %<latexrelease>\let \ReadonlyShipoutCounter \@undefined