Re: Fwd: Emacs hangs when "foo\\|\\|bar" is in `font-lock-keywords'

[Stefan Monnier <monnier@iro.umontreal.ca>]

> You could describe this as user-error, but I think it might be easy
> to make Font Lock bulletproof against null-matches in the regexps,
> at least enough to avoid infinite loops.

> Could someone please look at this and ack to me?

Would that do the trick,


        Stefan


Index: lisp/font-lock.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/font-lock.el,v
retrieving revision 1.268
diff -u -r1.268 font-lock.el
--- lisp/font-lock.el	4 Jul 2005 23:08:54 -0000	1.268
+++ lisp/font-lock.el	11 Jul 2005 21:43:36 -0000
@@ -1473,8 +1473,12 @@
       (while (and (< (point) end)
 		  (if (stringp matcher)
 		      (re-search-forward matcher end t)
-		    (funcall matcher end)))
-	(when (and font-lock-multiline
+		    (funcall matcher end))
+                  ;; Beware empty string matches since they will
+                  ;; loop indefinitely.
+                  (or (> (point) (match-beginning 0))
+                      (progn (forward-char 1) t)))
+        (when (and font-lock-multiline
 		   (>= (point)
 		       (save-excursion (goto-char (match-beginning 0))
 				       (forward-line 1) (point))))