Fix result of \@ifdefinable on the empty cs

fixes #778
latex3 · Jun 13, 2022 · 952afcb · 952afcb
1 parent ec35ad5
commit 952afcb
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Showing 3 changed files with 54 additions and 6 deletions.
diff --git a/base/ltdefns.dtx b/base/ltdefns.dtx
@@ -32,7 +32,7 @@
 %<*driver>
 % \fi
 \ProvidesFile{ltdefns.dtx}
-             [2022/05/13 v1.5q LaTeX Kernel (definition commands)]
+             [2022/06/12 v1.5r LaTeX Kernel (definition commands)]
 % \iffalse
 \documentclass{ltxdoc}
 \GetFileInfo{ltdefns.dtx}
@@ -671,23 +671,46 @@
 % \changes{v1.0n}{1994/05/10}{Removed braces around \cs{@ifundefined}
 %    argument.  ASAJ.}
 % \changes{v1.0s}{1994/05/13}{Coded more efficiently, thanks to FMi.}
+% \changes{v1.5r}{2022/06/12}{Fix result of \cs{@ifdefinable} on the empty cs (gh/778).}
 %
 %  \begin{macro}{\@ifdefinable}
 %  \begin{macro}{\@@ifdefinable}
 %  \begin{macro}{\@rc@ifdefinable}
 %    Test if user is allowed to define a command.
 %    \begin{macrocode}
+%</2ekernel>
+%<*2ekernel|latexrelease>
+%<latexrelease>\IncludeInRelease{2022/11/01}{\@ifdefinable}
+%<latexrelease>                 {Fix \cs{@ifdefinable} on the empty cs}%
 \long\def\@ifdefinable #1#2{%
       \edef\reserved@a{\expandafter\@gobble\string #1}%
-     \@ifundefined\reserved@a
+     \@expl@cs@if@free@@NTF #1%
          {\edef\reserved@b{\expandafter\@carcube \reserved@a xxx\@nil}%
           \ifx \reserved@b\@qend \@notdefinable\else
             \ifx \reserved@a\@qrelax \@notdefinable\else
               #2%
             \fi
           \fi}%
          \@notdefinable}
+%<latexrelease>\EndIncludeInRelease
+%<latexrelease>
+%<latexrelease>\IncludeInRelease{0000/00/00}{\@ifdefinable}
+%<latexrelease>                 {Fix \cs{@ifdefinable} on the empty cs}%
+%<latexrelease>\long\def\@ifdefinable #1#2{%
+%<latexrelease>      \edef\reserved@a{\expandafter\@gobble\string #1}%
+%<latexrelease>     \@ifundefined\reserved@a
+%<latexrelease>         {\edef\reserved@b{\expandafter\@carcube \reserved@a xxx\@nil}%
+%<latexrelease>          \ifx \reserved@b\@qend \@notdefinable\else
+%<latexrelease>            \ifx \reserved@a\@qrelax \@notdefinable\else
+%<latexrelease>              #2%
+%<latexrelease>            \fi
+%<latexrelease>          \fi}%
+%<latexrelease>         \@notdefinable}
+%<latexrelease>\EndIncludeInRelease
+%</2ekernel|latexrelease>
+%<*2ekernel>
 %    \end{macrocode}
+%
 %    Saved definition of |\@ifdefinable|.
 %    \begin{macrocode}
 \let\@@ifdefinable\@ifdefinable

diff --git a/base/ltexpl.dtx b/base/ltexpl.dtx
@@ -33,7 +33,7 @@
 %<*driver>
 % \fi
 \ProvidesFile{ltexpl.dtx}
-             [2022/02/28 v1.3f LaTeX Kernel (expl3-dependent code)]
+             [2022/06/12 v1.3g LaTeX Kernel (expl3-dependent code)]
 % \iffalse
 \documentclass{ltxdoc}
 \GetFileInfo{ltexpl.dtx}
@@ -371,6 +371,12 @@
 \cs_gset_eq:NN \@expl@char@generate@@nn \char_generate:nn
 %    \end{macrocode}
 %
+% \changes{v1.3g}{2022/06/12}
+%         {Add \cs{@expl@cs@if@free@@NTF} for \cs{@ifdefinable} (gh/778)}
+%    \begin{macrocode}
+\cs_gset_eq:NN \@expl@cs@if@free@@NTF \cs_if_free:NTF
+%    \end{macrocode}
+%
 %    \begin{macrocode}
 \ExplSyntaxOff
 %    \end{macrocode}
@@ -390,6 +396,7 @@
 %<latexrelease>\let \@expl@cs@argument@spec@@N \@undefined
 %<latexrelease>\let \@expl@cs@replacement@spec@@N \@undefined
 %<latexrelease>\let \@expl@str@map@function@@NN \@undefined
+%<latexrelease>% \let \@expl@cs@if@free@@NTF \@undefined
 %<latexrelease>\EndIncludeInRelease
 %</2ekernel|latexrelease>
 %    \end{macrocode}

diff --git a/base/testfiles/github-0778.tlg b/base/testfiles/github-0778.tlg
@@ -11,14 +11,32 @@ If that doesn't work, type  X <return>  to quit.
 ->A.
 <argument> \csname\endcsname
 l. ......ndafter}\expandafter\test\csname\endcsname
-> \csname\endcsname=\long macro:
-->B.
-<argument> \csname\endcsname
+! LaTeX Error: Command \csname\endcsnamealready defined.
+               Or name \end... illegal, see p.192 of the manual.
+See the LaTeX manual or LaTeX Companion for explanation.
+Type  H <return>  for immediate help.
+ ...                                              
 l. ......ndafter}\expandafter\test\csname\endcsname
+Your command was ignored.
+Type  I <command> <return>  to replace it with another command,
+or  <return>  to continue without it.
 > \csname\endcsname=\long macro:
 ->A.
 <argument> \csname\endcsname
 l. ......ndafter}\expandafter\test\csname\endcsname
+! LaTeX Error: Command \csname\endcsnamealready defined.
+               Or name \end... illegal, see p.192 of the manual.
+See the LaTeX manual or LaTeX Companion for explanation.
+Type  H <return>  for immediate help.
+ ...                                              
+l. ......ndafter}\expandafter\test\csname\endcsname
+Your command was ignored.
+Type  I <command> <return>  to replace it with another command,
+or  <return>  to continue without it.
+> \csname\endcsname=macro:
+->\romannumeral \ifx \protect \@typeset@protect \expandafter \expandafter \expandafter \expandafter \expandafter \expandafter \expandafter \z@ \else \expandafter \z@ \expandafter \protect \fi \end  .
+<argument> \csname\endcsname
+l. ......ndafter}\expandafter\test\csname\endcsname
 > \end=\long macro:
 ->B.
 \test ...onment {}{A}{B} \par \show #1 \show \end