[latex3-commits] [git/LaTeX3-latex3-latex2e] gh963: Better not leave side effects if not defining (401a6215)

[PhelypeOleinik]

Repository : https://github.com/latex3/latex2e
On branch  : gh963
Link       : https://github.com/latex3/latex2e/commit/401a621546946359f1df95a1335c8a3739208008

>---------------------------------------------------------------

commit 401a621546946359f1df95a1335c8a3739208008
Author: PhelypeOleinik <phelype.oleinik at latex-project.org>
Date:   Mon Nov 28 01:43:33 2022 -0300

    Better not leave side effects if not defining


>---------------------------------------------------------------

401a621546946359f1df95a1335c8a3739208008
 base/ltdefns.dtx                     | 7 +++----
 base/testfiles-ltcmd/github-0963.tlg | 2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/base/ltdefns.dtx b/base/ltdefns.dtx
index d2ffc578..7f3fa140 100644
--- a/base/ltdefns.dtx
+++ b/base/ltdefns.dtx
@@ -1733,11 +1733,10 @@
     {\@firstofone}%
     {\@firstofone}}
 \long\def\declare at environmentcopy#1#2#3#4{%
-  \def\reserved at a{#3}%
+  \edef\reserved at a{\@ifundefined{#3}{end#3}{#3}}%
   \@ifundefined\reserved at a
-    {\expandafter\let\csname #3\expandafter\endcsname
-                     \csname end#3\endcsname}{}%
-  \@ifundefined\reserved at a{#1}{#2}%
+      {\def\reserved at a{#3}#1}%
+      {\def\reserved at a{#3}#2}%
     {\ExpandArgs{cc}\declare at commandcopy@do{#3}{#4}%
      \ExpandArgs{cc}\declare at commandcopy@do{end#3}{end#4}}}
 %    \end{macrocode}
diff --git a/base/testfiles-ltcmd/github-0963.tlg b/base/testfiles-ltcmd/github-0963.tlg
index 5c8256cc..77016a91 100644
--- a/base/testfiles-ltcmd/github-0963.tlg
+++ b/base/testfiles-ltcmd/github-0963.tlg
@@ -67,7 +67,7 @@ l. ...\NewEnvironmentCopy{group}{foo}
 Your command was ignored.
 Type  I <command> <return>  to replace it with another command,
 or  <return>  to continue without it.
-> \group=\endgroup.
+> \group=undefined.
 l. ...\show\group
 > \endgroup=\endgroup.
 l. ...\show\endgroup