Re: emacs-27 3bce7ec: CC Mode: Protect against consecutive calls to before-change-functions ...

[Mattias Engdegård]

28 feb. 2020 kl. 17.54 skrev Glenn Morris <address@hidden>:

>>   CC Mode: Protect against consecutive calls to before-change-functions ...
> 
> This causes srecode-utest-getset-output in
> test/lisp/cedet/srecode-utest-getset.el to fail:

Indeed, and so does electric-tests. Condensed reproduction:

(with-temp-buffer
  (c-mode)
  (insert "a")
  (comment-region (point-min) (point-max)))

Alan, it looks like the code has lost control over c-new-END. c-after-change 
over-adjusts it to a value beyond the buffer size.
The problem seems to go away with the expedient below but it is unlikely to be 
the right solution.

--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -2006,7 +2006,8 @@ c-after-change
 
   ;; (c-new-BEG c-new-END) will be the region to fontify.  It may become
   ;; larger than (beg end).
-  (setq c-new-END (- (+ c-new-END (- end beg)) old-len))
+  (setq c-new-END (min (- (+ c-new-END (- end beg)) old-len)
+                      (point-max)))
 
   (unless (c-called-from-text-property-change-p)
     (setq c-just-done-before-change nil)