bug#3494: 23.0.94; line-move-visual: temporary goal column confused by hscrolling

[Teemu Likonen <tlikonen@iki.fi>]

On 2009-07-11 18:59 (-0400), Chong Yidong wrote:

> I can't reproduce it. Your recipe is missing one step: C-x C-n is a
> disabled command, so you need to type "y" to enable it, as I presume
> you intended. I don't observe any column change, though.
>
> Did you do xrdb -remove beforehand? (I can't reproduce the problem
> with or without Xresource settings.) What's the size of your Emacs
> frame?

Yes, I enabled the disabled set-goal-column command with "y". The bug
appears on terminal too. Here's another, even more accurate recipe what
I do. I uploaded screenshots too (see the link below). This time I use
Emacs in terminal:


 1. xrdb -remove; xterm -geometry 80x25

 2. emacs -Q -nw -f toggle-truncate-lines -f column-number-mode

 3. Create content exactly like this:

        C-u 85 a RET
        C-u 100 b RET

 4. Press C-p two times to move the the beginning of "a" line.

 5. Press C-e to get to the end of "a" line. (See screenshot 1.)

 6. Press C-x C-n and "y" to set goal column. This message is displayed:

        Goal column 85 (use C-x C-n with an arg to unset it)

 7. Press C-n. The screen is scrolled horizontally and the cursor at the
    column 94. (See screenshot 2.)


Let's continue to reproduce the bug which appears without goal column.

 8. Disable the goal column: C-u C-x C-n

 9. Move to the beginning of the "a" line.

10. Move to the end of the "a" line (C-e). Again the screen looks like
    in my first screenshot, see the item 5 above.

11. Press C-n to go the next line. The screen is scrolled horizontally
    and the cursor column is correct: 85. (See screenshot 3.)

12. Press C-p to go the previous line. The cursor stays on the "b" line
    but the cursor column is now 79. (See screenshot 4.)


None of these bugs appear when line-move-visual=nil.


Screenshots here:
http://dtw.silverentertainment.fi/pics/emacs/emacs-bug-3494.png