From: Eli Zaretskii <eliz@gnu.org>
Date: Fri, 28 May 2021 11:03:16 +0000 (+0300)
Subject: Another stability fix in 'lisp_string_width'
X-Git-Tag: emacs-28.0.90~2296
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=6d916bfb37d88a63663ad5777c8c3b83fbcfdbd0;p=emacs.git

Another stability fix in 'lisp_string_width'

* src/character.c (lisp_string_width): Compute C pointer to data
of STRING immediately before using it, since STRING could be
relocated by GC triggered by processing compositions.  (Bug#48711)
---

diff --git a/src/character.c b/src/character.c
index e44ab8d43b1..e874cf5e53c 100644
--- a/src/character.c
+++ b/src/character.c
@@ -339,7 +339,6 @@ lisp_string_width (Lisp_Object string, ptrdiff_t from, ptrdiff_t to,
      contains only ascii and eight-bit-graphic, but that's
      intentional.  */
   bool multibyte = SCHARS (string) < SBYTES (string);
-  unsigned char *str = SDATA (string);
   ptrdiff_t i = from, i_byte = from ? string_char_to_byte (string, from) : 0;
   ptrdiff_t from_byte = i_byte;
   ptrdiff_t width = 0;
@@ -414,6 +413,7 @@ lisp_string_width (Lisp_Object string, ptrdiff_t from, ptrdiff_t to,
       else
 	{
 	  int c;
+	  unsigned char *str = SDATA (string);
 
 	  if (multibyte)
 	    {