bug#17244: 24.3.90; `line-move-visual' errors when moving across wrapped lines with an overlay property of 'display

[Ivan Andrus <darthandrus@gmail.com>]

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Starting from Emacs -Q, create a buffer with the following contents.
Notice that the first two (2) lines are blank, and the next is one long
line (in case it gets broken by email)

#### buffer start:


;; I think this needs to be really long here.  Why?  I don't really know,
but a guess.  I think this needs to be really long here.  Why?  I don't
really know, but a guess.  I think this needs to be really long here.  Why?
 I don't really know, but a guess.  I think this needs to be really long
here.  Why?  I don't really know, but a guess.  I think this needs to be
really long here.  Why?  I don't really know, but a guess.  I think this
needs to be really long here.  Why?  I don't really know, but a guess.
(let ((ov (make-overlay 3 515)))
 (overlay-put ov 'display "hi\n"))
(line-move-visual -5)

1. Make sure the window is skinny enough that the comment line wraps.
2. Evaluate the first form, creating an overlay.
3. Evaluate the second form.  It is important that point be at the end
   of the "line-move-visual" line.
4. You get a warning about beginning-of-buffer, when it clearly did not
   reach the beginning-of-buffer.

As near as I can tell, the incorrect error message is because it doesn't
move as far at it thinks it should (the real bug), and it assumes the
reason it didn't is because it made it to the beginning (or end) of the
buffer.

-Ivan

In GNU Emacs 24.3.90.1 (x86_64-apple-darwin13.1.0, NS apple-appkit-1265.19)
of 2014-04-11 on iandrus-osx
Windowing system distributor `Apple', version 10.3.1265
Configured using:
`configure --with-ns'

Important settings:
 value of $LANG: en_US.UTF-8
 locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
 tooltip-mode: t
 electric-indent-mode: t
 mouse-wheel-mode: t
 tool-bar-mode: t
 menu-bar-mode: t
 file-name-shadow-mode: t
 global-font-lock-mode: t
 font-lock-mode: t
 blink-cursor-mode: t
 auto-composition-mode: t
 auto-encryption-mode: t
 auto-compression-mode: t
 line-number-mode: t
 transient-mark-mode: t

Recent input:
<down-mouse-1> <mouse-1> C-x C-e <down> C-x C-e <down-mouse-1>
<mouse-1> <up> <up> <up> <up> <up> <down> <down> <up>
<up> <down> <down> <up> <up> <down> <down> <down> <down>
<down> <up> <up> <up> <up> <up> <down> <down> <down>
<down> <down> <up> <up> <up> <up> <up> <down> <down>
<down> <down> <down> <down> C-x C-e <down> <down> <down>
<down> C-e C-x C-e <down-mouse-1> <mouse-1> <return>
SPC SPC SPC SPC SPC C-x C-e C-/ C-/ <help-echo> C-c
C-c s-x C-/ M-x m a i <tab> <C-backspace> r e p o <tab>
r t <tab> <return>

Recent messages:
line-move-visual: Beginning of buffer
Beginning of buffer [5 times]
t
line-move-visual: Beginning of buffer
t
Undo! [2 times]
C-c C-c is undefined
Undo!
Making completion list...
C-c C-c is undefined

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
help-fns mail-prsvr mail-utils help-mode easymenu vc-hg time-date
tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
ns-win tool-bar dnd fontset image regexp-opt fringe tabulated-list
newcomment lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai
tai-viet lao korean japanese hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help
simple abbrev minibuffer nadvice loaddefs button faces cus-face macroexp
files text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
cocoa ns multi-tty emacs)

Memory information:
((conses 16 74077 4946)
(symbols 48 17641 0)
(miscs 40 49 163)
(strings 32 10552 3708)
(string-bytes 1 281155)
(vectors 16 9174)
(vector-slots 8 367902 7774)
(floats 8 54 455)
(intervals 56 212 7)
(buffers 960 13))

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