Gh1638 (#1639)

* fix for #1638

* update rollback code

* extend the test to also cover extended syntax

* updates after review

* new text suggestion

* add a comment about commands defined elsewhere

base/changes.txt

@@ -6,15 +6,20 @@ to completeness or accuracy and it contains some references to files that are
 not part of the distribution.
 ================================================================================
 
+2025-01-23  Frank Mittelbach  <[email protected]>
+
+	* ltoutput.dtx (subsection{Floats}):
+	* ltsect.dtx (subsection{Table of Contents etc.}):
+	Make \label, \index, and \glossary truely invisible
+        when typesetting (gh/1638)
+
 2025-01-23  Joseph Wright  <[email protected]>
 	* ltcmd.dtx, usrguide.tex
 	New "c"-type argument
 
 2025-01-21  Frank Mittelbach  <[email protected]>
 
 	* ltoutput.dtx (subsection{Floats}):
-	Support extended syntax for \label, \index, and \glossary (gh/311)
-
 	* ltsect.dtx (subsection{Table of Contents etc.}):
 	Support extended syntax for \label, \index, and \glossary (gh/311)
 

base/doc/ltnews41.tex

@@ -466,15 +466,35 @@ \subsection{Process global options once per package}
 %
 \githubissue{1619}
 
+
+\subsection{Make \cs{label}, \cs{index}, and \cs{glossary} truely invisible in running headers}
+
+\LaTeX{} has had a bug since its initial implementation, in that it
+correctly ignored any \cs{label}, \cs{index}, or \cs{glossary}
+appearing in a mark, but neglected to handle the spaces around the
+command. As a result one could end up with two spaces in the running
+header when only one should be present. This was detected as part of
+working on issue~311 and has now been corrected.
+%
+\githubissue{1638}
+
+
+
 \section{Documentation}
+
 \subsection{Clarifying space handling of \cs{textcolor}}
 
-In contrast to other \cs{text}-commands like \cs{textbf} or \cs{textrm},
-the command \cs{textcolor} gobbles spaces at the start of its argument, so \verb=Hello\textcolor{red}{  World}= will output Hello\textcolor{red}{  World}.
-There are technical as well as compatibility reasons for this, so the behavior will not change. This has now been clarified in the documentation.
+In contrast to other \cs{text}-commands like \cs{textbf} or
+\cs{textrm}, the command \cs{textcolor} gobbles spaces at the start of
+its argument, so \verb*=Hello\textcolor{red}{ World}= will output
+Hello\textcolor{red}{ World}.  There are technical as well as
+compatibility reasons for this, so the behavior will not change. This
+has now been clarified in the documentation.
 %
 \githubissue{1474}
 
+
+
 %\section{Changes to packages in the \pkg{amsmath} category}
 
 \section{Changes to packages in the \pkg{graphics} category}

base/ltdefns.dtx

@@ -32,7 +32,7 @@
 %<*driver>
 % \fi
 \ProvidesFile{ltdefns.dtx}
-             [2024/09/06 v1.5t LaTeX Kernel (definition commands)]
+             [2025/01/24 v1.5t LaTeX Kernel (definition commands)]
 % \iffalse
 \documentclass{ltxdoc}
 \GetFileInfo{ltdefns.dtx}
@@ -943,6 +943,15 @@
 % \end{macro}
 % \end{macro}
 %
+% There are also \cs{@gobble@om}, \cs{@gobble@som},
+% \cs{@gobble@with@sphack@om}, and \cs{@gobble@with@sphack@som}. They
+% accept an optional and a mandatory argument, possibly preceeded by a
+% star. In all cases the expansion is empty or just manipulates the
+% spaces around the command.  Used to disable commands such as
+% \cs{index} or \cs{label} in certain situations.  Since they are
+% defined with \cs{DeclareDocumentCommand}, which is not yet available
+% at this point, the actual definition happens in \texttt{ltsect.dtx}.
+%
 % \begin{macro}{\@firstofone}
 % \begin{macro}{\@firstoftwo}
 % \begin{macro}{\@secondoftwo}

base/ltoutput.dtx

@@ -30,7 +30,7 @@
 %%% From File: ltoutput.dtx
 %<flafter>\ProvidesPackage{flafter}
 %<fltrace>\ProvidesPackage{fltrace}
-%<flafter,fltrace>       [2025/01/21 v1.4l
+%<flafter,fltrace>       [2025/01/23 v1.4m
 %<flafter>                  Standard LaTeX floats after reference (FMi)]
 %<fltrace>                  Tracing LaTeX floats algorithm (FMi)]
 %
@@ -2201,10 +2201,13 @@
 %     {Move \cs{label} and \cs{index} (from patch file)}
 % \changes{v1.4l}{2025/01/21}{Support extended syntax
 %            for \cs{label}, \cs{index}, and \cs{glossary} (gh/311)}
+%  \changes{v1.4m}{2025/01/23}
+%     {Make \cs{label}, \cs{index} and \cs{glossary} truely invisible
+%    when typesetting (gh/1638)}
 %    \begin{macrocode}
-  \let\label\@gobble@om
-  \let\index\@gobble@som
-  \let\glossary\@gobble@om
+  \let\label\@gobble@with@sphack@om
+  \let\index\@gobble@with@sphack@som
+  \let\glossary\@gobble@with@sphack@om
 %    \end{macrocode}
 %
 %    \begin{macrocode}

base/ltsect.dtx

@@ -31,7 +31,7 @@
 %%% From File: ltsect.dtx
 %<*driver>
 % \fi
-\ProvidesFile{ltsect.dtx}[2025/01/21 v1.1g LaTeX Kernel (Sectioning)]
+\ProvidesFile{ltsect.dtx}[2025/01/23 v1.1h LaTeX Kernel (Sectioning)]
 % \iffalse
 \documentclass{ltxdoc}
 \GetFileInfo{ltsect.dtx}
@@ -819,23 +819,38 @@
 %
 %
 %
-%  \begin{macro}{\@gobble@om,\@gobble@som}
-%    Two commands that accept an optional and a mandatory argument or
-%    a star, optional and mandatory argument and then do nothing. Used
-%    to disable commands such as \cs{index} in certain situations.
-%  \changes{v1.1g}{2025/01/21}
-%     {Support extended syntax for \cs{label}, \cs{index} and \cs{glossary} (gh/311)}
+%  \begin{macro}{\@gobble@om,\@gobble@som,\@gobble@with@sphack@om,\@gobble@with@sphack@som}
+%
+%    Each of these four commands accepts an optional and a mandatory
+%    argument, possibly preceeded by a star. In all cases the
+%    expansion is empty or just manipulates the spaces around the command.
+%    Used to disable commands such as \cs{index}
+%    or \cs{label} in certain situations.
 %    \begin{macrocode}
 %</2ekernel>
 %<*2ekernel|latexrelease>
 %<latexrelease>\IncludeInRelease{2025/06/01}%
 %<latexrelease>                 {\@gobble@som}{Extended index/label}%
 %    \end{macrocode}
 %
+%    Just getting rid of the input in an expandable way is done by these two.
+%  \changes{v1.1g}{2025/01/21}
+%     {Support extended syntax for \cs{label}, \cs{index} and \cs{glossary} (gh/311)}
 %    \begin{macrocode}
 \DeclareExpandableDocumentCommand\@gobble@om{+o+m}{}
 \DeclareExpandableDocumentCommand\@gobble@som{s+o+m}{}
 %    \end{macrocode}
+%
+%    When something needs to be suppressed during typesetting, one often
+%    also wants to ensure that this doesn't end up with two spaces (in
+%    case there is one before and one after). This can't be done expandably.
+%  \changes{v1.1h}{2025/01/23}
+%     {Make \cs{label}, \cs{index} and \cs{glossary} truely invisible
+%    when typesetting (gh/1638)}
+%    \begin{macrocode}
+\DeclareDocumentCommand\@gobble@with@sphack@om{+o+m}{\@bsphack\@esphack}
+\DeclareDocumentCommand\@gobble@with@sphack@som{s+o+m}{\@bsphack\@esphack}
+%    \end{macrocode}
 %  \end{macro}
 %
 %
@@ -874,6 +889,8 @@
 %<latexrelease>
 %<latexrelease>\let\@gobble@om\@undefined
 %<latexrelease>\let\@gobble@som\@undefined
+%<latexrelease>\let\@gobble@with@sphack@om\@undefined
+%<latexrelease>\let\@gobble@with@sphack@som\@undefined
 %<latexrelease>\EndIncludeInRelease
 %<*2ekernel>
 %    \end{macrocode}

base/testfiles/github-1638.lvt

@@ -0,0 +1,27 @@
+% Showed 2 spaces in running header, but one (correct) in TOC.
+%
+% Also test extended syntax (which has no separate test).
+%
+% As neither \label nor \index has an extended syntax so far you get strange
+% output in the heading, but the TOC and the running header is ok.
+
+\documentclass{book}
+
+\input{regression-test}
+
+\makeindex
+\pagestyle{headings}
+
+\showoutput
+
+\begin{document}
+
+\START
+
+\tableofcontents
+
+\chapter{X \index{blub} X \index*{abc} X \index[foo]{xyz} X  X}
+\section{Y \label{bla} Y \label[foo]{bar} Y  Y}
+x \newpage x \newpage x \newpage
+\OMIT
+\end{document}