fix for #1407 (#1408)

* fix for #1407

* corrections

* further suggestions by CAR

base/changes.txt

@@ -6,6 +6,12 @@ to completeness or accuracy and it contains some references to files that are
 not part of the distribution.
 ================================================================================
 
+2024-07-10 Frank Mittelbach <[email protected]>
+
+ * ltmiscen.dtx (subsection{Environments}):
+ Drop code chunks before adding them to avoid duplication in
+ rollback (gh/1407)
+
 2024-07-06 Yukai Chou <[email protected]>
 
  * ltcmd.dtx (subsection{User functions}):

base/doc/ltnews40.tex

@@ -273,6 +273,19 @@ \section{Improvement to \XeTeX\ \cs{showhyphens}}
 %
 \githubissue{1380}
 
+\section{Avoid code duplication in rollback}
+
+When the kernel uses \cs{AddToHook} in a region that might be 
+rolled back (which happens in a few places) and a document requests a
+rollback, then we have the situation that the hook already contains code to which we added the same
+(or slightly different) code during the
+rollback; this results in code duplication or, worse, in errors. This has
+now been corrected by dropping any such code chunk (if there is one) prior to
+adding the rollback code.
+%
+\githubissue{1407}
+
+
 %\section{Changes to packages in the \pkg{amsmath} category}
 
 %\section{Changes to packages in the \pkg{graphics} category}

base/ltmiscen.dtx

@@ -32,7 +32,7 @@
 %<*driver>
 % \fi
 \ProvidesFile{ltmiscen.dtx}
- [2024/06/23 v1.2d LaTeX Kernel (Misc. Environments)]
+ [2024/07/10 v1.2e LaTeX Kernel (Misc. Environments)]
 % \iffalse
 \documentclass{ltxdoc}
 \GetFileInfo{ltmiscen.dtx}
@@ -276,6 +276,21 @@
 % \changes{v1.0w}{1994/11/30}{(DPC) Use \cs{@dofilelist}}
 % \changes{v1.2a}{2022/11/06}{Repeat release info at the end (gh/944)}
 % \begin{macrocode}
+% \end{macrocode}
+% If we roll back we have to drop stuff before adding chunks,
+% otherwise the code will just be appended, and thus doubled.
+% This would result in a harmless warning during the format
+% generation, because in that case the code chunk label doesn't
+% exist, and therefore can't be dropped.
+% \changes{v1.2e}{2024/07/10}{Drop code chunks before adding them to
+% avoid duplication in rollback (gh/1407)}
+% \begin{macrocode}
+%<latexrelease>\RemoveFromHook{enddocument/info}[kernel/filelist]
+%<latexrelease>\RemoveFromHook{enddocument/info}[kernel/warnings]
+%<latexrelease>\RemoveFromHook{enddocument/info}[kernel/release]
+% \end{macrocode}
+%
+% \begin{macrocode}
 \AddToHook{enddocument/info}[kernel/filelist]{\@dofilelist}
 \AddToHook{enddocument/info}[kernel/warnings]{\@enddocument@kernel@warnings}
 \AddToHook{enddocument/info}[kernel/release]{%
@@ -389,6 +404,18 @@
 %<latexrelease>\NewHook{enddocument/afteraux}
 %<latexrelease>\NewHook{enddocument/info}
 %<latexrelease>\NewHook{enddocument/end}
+% \end{macrocode}
+% If we roll back we have to drop stuff before adding chunks,
+% otherwise the code will just be appended, and thus doubled.
+% \changes{v1.2e}{2024/07/10}{Drop code chunks before adding them to
+% avoid duplication in rollback (gh/1407)}
+% \begin{macrocode}
+%<latexrelease>\RemoveFromHook{enddocument/info}[kernel/filelist]
+%<latexrelease>\RemoveFromHook{enddocument/info}[kernel/warnings]
+%<latexrelease>\RemoveFromHook{enddocument/info}[kernel/release]
+% \end{macrocode}
+%
+% \begin{macrocode}
 %<latexrelease>\AddToHook{enddocument/info}[kernel/filelist]{\@dofilelist}
 %<latexrelease>\AddToHook{enddocument/info}[kernel/warnings]{\@enddocument@kernel@warnings}
 %<latexrelease>\AddToHook{enddocument/info}[kernel/release]{%

base/testfiles/github-1407-rollback.lvt

@@ -0,0 +1,13 @@
+\RequirePackage[2023-11-01]{latexrelease}
+
+\documentclass{article}
+
+\input{test2e}
+
+
+\START
+
+\typeout{--> Code should not be doubled in chunks}
+
+\ShowHook{enddocument/info}
+\END

base/testfiles/github-1407-rollback.tlg

@@ -0,0 +1,21 @@
+This is a generated file for the LaTeX2e validation system.
+Don't change this file in any respect.
+--> Code should not be doubled in chunks
+-> The hook 'enddocument/info':
+> Code chunks:
+> kernel/filelist -> \@dofilelist 
+> kernel/warnings -> \@enddocument@kernel@warnings 
+> kernel/release -> \let \show@release@info \wlog \show@release@info { ***********}\the \LaTeXReleaseInfo \show@release@info { ***********}
+> kernel/testmode -> 
+> Document-level (top-level) code (executed last):
+> ---
+> Extra code for next invocation:
+> ---
+> Rules:
+> kernel/warnings|kernel/filelist with relation >
+> kernel/release|kernel/filelist with relation <
+> kernel/testmode|kernel/release with relation ->
+> Execution order (after applying rules):
+> kernel/release, kernel/testmode, kernel/filelist, kernel/warnings.
+<recently read> }
+l. ...\ShowHook{enddocument/info}