bug#2435: Bug 2435

[Chong Yidong]

The following patch tries to avoid the problem by updating the regexp
list before using the regexp cell.  It seems to fix the problem; or do
have a different suggestion?

*** trunk/src/search.c.~1.237.~ 2009-02-12 16:45:29.000000000 -0500
--- trunk/src/search.c  2009-03-04 23:38:35.000000000 -0500
***************
*** 134,140 ****
    char *val;
    reg_syntax_t old;
  
!   cp->regexp = Qnil;
    cp->buf.translate = (! NILP (translate) ? translate : make_number (0));
    cp->posix = posix;
    cp->buf.multibyte = STRING_MULTIBYTE (pattern);
--- 134,140 ----
    char *val;
    reg_syntax_t old;
  
!   cp->regexp = Qt;
    cp->buf.translate = (! NILP (translate) ? translate : make_number (0));
    cp->posix = posix;
    cp->buf.multibyte = STRING_MULTIBYTE (pattern);
***************
*** 239,245 ****
         nil should never appear before a non-nil entry.  */
        if (NILP (cp->regexp))
        goto compile_it;
!       if (SCHARS (cp->regexp) == SCHARS (pattern)
          && STRING_MULTIBYTE (cp->regexp) == STRING_MULTIBYTE (pattern)
          && !NILP (Fstring_equal (cp->regexp, pattern))
          && EQ (cp->buf.translate, (! NILP (translate) ? translate : 
make_number (0)))
--- 239,246 ----
         nil should never appear before a non-nil entry.  */
        if (NILP (cp->regexp))
        goto compile_it;
!       if (STRINGP (cp->regexp)
!         && SCHARS (cp->regexp) == SCHARS (pattern)
          && STRING_MULTIBYTE (cp->regexp) == STRING_MULTIBYTE (pattern)
          && !NILP (Fstring_equal (cp->regexp, pattern))
          && EQ (cp->buf.translate, (! NILP (translate) ? translate : 
make_number (0)))
***************
*** 248,273 ****
              || EQ (cp->syntax_table, current_buffer->syntax_table))
          && !NILP (Fequal (cp->whitespace_regexp, Vsearch_spaces_regexp))
          && cp->buf.charset_unibyte == charset_unibyte)
!       break;
  
        /* If we're at the end of the cache, compile into the nil cell
         we found, or the last (least recently used) cell with a
!        string value.  */
        if (cp->next == 0)
        {
        compile_it:
          compile_pattern_1 (cp, pattern, translate, regp, posix);
          break;
        }
      }
  
-   /* When we get here, cp (aka *cpp) contains the compiled pattern,
-      either because we found it in the cache or because we just compiled it.
-      Move it to the front of the queue to mark it as most recently used.  */
-   *cpp = cp->next;
-   cp->next = searchbuf_head;
-   searchbuf_head = cp;
- 
    /* Advise the searching functions about the space we have allocated
       for register data.  */
    if (regp)
--- 249,279 ----
              || EQ (cp->syntax_table, current_buffer->syntax_table))
          && !NILP (Fequal (cp->whitespace_regexp, Vsearch_spaces_regexp))
          && cp->buf.charset_unibyte == charset_unibyte)
!       {
!         /* We found a compiled pattern.  Move it to the front of the
!            queue to mark it as most recently used.  */
!         *cpp = cp->next;
!         cp->next = searchbuf_head;
!         searchbuf_head = cp;
!         break;
!       }
  
        /* If we're at the end of the cache, compile into the nil cell
         we found, or the last (least recently used) cell with a
!        string value.  We must update the queue before calling
!        compile_pattern_1, because compile_pattern_1 can end up
!        calling compile_pattern recursively (via load_charset).  */
        if (cp->next == 0)
        {
        compile_it:
+         *cpp = cp->next;
+         cp->next = searchbuf_head;
+         searchbuf_head = cp;
          compile_pattern_1 (cp, pattern, translate, regp, posix);
          break;
        }
      }
  
    /* Advise the searching functions about the space we have allocated
       for register data.  */
    if (regp)