Subject: Re: bug#16695: 24.3; comment-dwim (args out of range)

From: Alan Mackenzie <[email-masked]>
Date: Sat, 8 Feb 2014 22:51:07 +0000

Hi, Glenn.

On Sat, Feb 08, 2014 at 03:12:20PM -0500, Glenn Morris wrote:
> [email-masked] wrote:

> > this is a longstanding bug since 24.3(i don't tried older versions)
> > till now (the latest git version - github mirror), and is very
> > annoying. it happens when trying to comment out (a line/multiple
> > lines) except the first line from a C family file that:

> > it's first line isn't empty or a comment.
> > isn't modified after it's opened.

> > comment function: comment-dwim (M-;)
> > emacs args: emacs -Q

> Thanks. For future reference, please do

>  M-x toggle-debug-on-error

> and include the basktrace in the report:

> Debugger entered--Lisp error: (args-out-of-range 1 2)
>   remove-text-properties(#<marker at 1 in foo.c> 2 (category nil))
>   c-invalidate-state-cache(17)
>   c-before-change(17 17)
>   comment-region-internal(17 45 "/* " " */" nil nil nil nil t)
>   comment-region-default(16 46 nil)
>   comment-region(16 46 nil)
>   comment-or-uncomment-region(16 46 nil)
>   comment-dwim(nil)
>   call-interactively(comment-dwim nil nil)
>   command-execute(comment-dwim)

I think this is the same bug as #16585, which I've just posted a patch
for.  Here is the patch again.  After applying this patch, recompile
progmodes/cc-defs.el, then recompile progmodes/cc-engine.el.

To the Original Poster: please try this out, and confirm it fixes the
bug.  Thanks!

=== modified file 'lisp/progmodes/cc-defs.el'
*** lisp/progmodes/cc-defs.el	2014-02-02 10:25:29 +0000
--- lisp/progmodes/cc-defs.el	2014-02-08 22:21:01 +0000
***************
*** 1293,1302 ****
    ;; suppressed.
    `(unwind-protect
         (c-save-buffer-state ()
! 	 (c-clear-cpp-delimiters ,beg ,end)
  	 ,`(c-with-cpps-commented-out ,@forms))
       (c-save-buffer-state ()
!        (c-set-cpp-delimiters ,beg ,end))))
  
  (defsubst c-intersect-lists (list alist)
    ;; return the element of ALIST that matches the first element found
--- 1293,1306 ----
    ;; suppressed.
    `(unwind-protect
         (c-save-buffer-state ()
! 	 (save-restriction
! 	   (widen)
! 	   (c-clear-cpp-delimiters ,beg ,end))
  	 ,`(c-with-cpps-commented-out ,@forms))
       (c-save-buffer-state ()
!        (save-restriction
! 	 (widen)
! 	 (c-set-cpp-delimiters ,beg ,end)))))
  
  (defsubst c-intersect-lists (list alist)
    ;; return the element of ALIST that matches the first element found

-- 
Alan Mackenzie (Nuremberg, Germany).