[Emacs-diffs] trunk r117752: Fix bug #18339 with segfault when $ is typed into empty LaTeX buffer.

[Eli Zaretskii]

------------------------------------------------------------
revno: 117752
revision-id: address@hidden
parent: address@hidden
fixes bug: http://debbugs.gnu.org/18339
committer: Eli Zaretskii <address@hidden>
branch nick: trunk
timestamp: Wed 2014-08-27 22:40:54 +0300
message:
  Fix bug #18339 with segfault when $ is typed into empty LaTeX buffer.
  
   src/syntax.c (scan_lists): Don't examine positions before BEGV.
modified:
  src/ChangeLog                  changelog-20091113204419-o5vbwnq5f7feedwu-1438
  src/syntax.c                   syntax.c-20091113204419-o5vbwnq5f7feedwu-180

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2014-08-27 18:56:47 +0000
+++ b/src/ChangeLog     2014-08-27 19:40:54 +0000
@@ -1,3 +1,8 @@
+2014-08-27  Eli Zaretskii  <address@hidden>
+
+       * syntax.c (scan_lists): Don't examine positions before BEGV.
+       (Bug#18339)
+
 2014-08-27  Paul Eggert  <address@hidden>
 
        Improve robustness of new string-collation code (Bug#18051).

=== modified file 'src/syntax.c'
--- a/src/syntax.c      2014-07-09 23:39:58 +0000
+++ b/src/syntax.c      2014-08-27 19:40:54 +0000
@@ -2857,10 +2857,13 @@
            case Smath:
              if (!sexpflag)
                break;
-             temp_pos = dec_bytepos (from_byte);
-             UPDATE_SYNTAX_TABLE_BACKWARD (from - 1);
-             if (from != stop && c == FETCH_CHAR_AS_MULTIBYTE (temp_pos))
-               DEC_BOTH (from, from_byte);
+             if (from > BEGV)
+               {
+                 temp_pos = dec_bytepos (from_byte);
+                 UPDATE_SYNTAX_TABLE_BACKWARD (from - 1);
+                 if (from != stop && c == FETCH_CHAR_AS_MULTIBYTE (temp_pos))
+                   DEC_BOTH (from, from_byte);
+               }
              if (mathexit)
                {
                  mathexit = 0;