bug#17585: 24.4.50; vertical-motion erroneously adds points

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 25 May 2014 00:23:20 -0700
> From: Keith David Bershatsky <esq@lawlist.com>
> 
> The following test function demonstrates how vertical-motion erroneously adds points when dealing with long lines without spaces that go beyond the window-width:
> 
>     (defun test ()
>     (interactive)
>       (switch-to-buffer (get-buffer-create "foo.txt"))
>       (text-mode)
>       (linum-mode t)
>       (visual-line-mode t)
>       (dotimes (i (* (window-width) 4))
>         (insert ";"))
>      (dotimes (i 10)
>         (insert "\n"))
>       (goto-char (point-min))
>       (vertical-motion 1)
>       (message "Second Row + 2 points:  %s" (current-column))
>       (vertical-motion 1)
>       (message "Third Row + 4 points:  %s" (current-column)))

Fixed in revision 117154 on the emacs-24 branch.  The patch is below,
in case you want to try it without waiting for it to be merged to the
trunk.

Thanks.

--- src/xdisp.c	2014-05-24 21:28:43 +0000
+++ src/xdisp.c	2014-05-25 14:18:46 +0000
@@ -8556,7 +8556,7 @@ move_it_in_display_line_to (struct it *i
 	}
       else
 	{
-	  if (it->line_wrap == WORD_WRAP)
+	  if (it->line_wrap == WORD_WRAP && it->area == TEXT_AREA)
 	    {
 	      if (IT_DISPLAYING_WHITESPACE (it))
 		may_wrap = 1;