Subject: bug#62009: 29.0.60; Emacs crashes on setf symbol-name

From: Gregory Heytings <[email-masked]>
Date: Sat, 18 Mar 2023 22:46:35 +0000

>
> I think being a bit vague here and talking about "dangers" should be 
> good enough, since not every such code will crash, and probably also not 
> on every platform and in every build configuration.
>

Is the attached patch okay?
From 32f0fe0aa5fce7fd71f80a166676ef3e5f1e7b32 Mon Sep 17 00:00:00 2001
From: Gregory Heytings <[email-masked]>
Date: Sat, 18 Mar 2023 22:41:33 +0000
Subject: [PATCH] Improve warning about changing the string returned by
 symbol-name

* src/data.c (Fsymbol_name): Add warning.

* doc/lispref/symbols.texi (Creating Symbols): Improve warning.
---
 doc/lispref/symbols.texi | 5 ++---
 src/data.c               | 5 ++++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/doc/lispref/symbols.texi b/doc/lispref/symbols.texi
index 5b53cbe310a..c6a0408abd1 100644
--- a/doc/lispref/symbols.texi
+++ b/doc/lispref/symbols.texi
@@ -276,9 +276,8 @@ Creating Symbols
 @end group
 @end example
 
-@strong{Warning:} Changing the string by substituting characters does
-change the name of the symbol, but fails to update the obarray, so don't
-do it!
+@strong{Warning:} Never alter the string returned by that function.
+Doing that might make Emacs dysfunctional, and might even crash Emacs.
 @end defun
 
 @cindex uninterned symbol, and generating Lisp code
diff --git a/src/data.c b/src/data.c
index 0f1d881e00b..930d476bc3f 100644
--- a/src/data.c
+++ b/src/data.c
@@ -773,7 +773,10 @@ DEFUN ("symbol-plist", Fsymbol_plist, Ssymbol_plist, 1, 1, 0,
 }
 
 DEFUN ("symbol-name", Fsymbol_name, Ssymbol_name, 1, 1, 0,
-       doc: /* Return SYMBOL's name, a string.  */)
+       doc: /* Return SYMBOL's name, a string.
+
+Warning: never alter the string returned by `symbol-name'.
+Doing that might make Emacs dysfunctional, and might even crash Emacs.  */)
   (register Lisp_Object symbol)
 {
   register Lisp_Object name;
-- 
2.39.0