Re: Sudden jumping point in buffer. Probably a bug?

["Stefan-W. Hahn" <stefan.hahn@s-hahn.de>]

Mail von Dmitry Gutov, Wed, 18 Nov 2015 at 20:57:04 +0200:
> On 11/18/2015 08:49 PM, Eli Zaretskii wrote:

Hello,

> >>I'm using emacs as 64 bit compiled on windows 7/64 and linux 64 bit. Since
> >>quite a while I have the problem that, while typing, the cursor (point) is
> >>sometimes suddenly jumping to another position in buffer.
> >
> >Does this happen in "emacs -Q"?  If not, look for a deviant timer or a

I tried this and it doesn't happen. But this does not say anthing because it
is not reproducible anyway.

> >post-command-hook set up by some of your customizations and optional
> >features you load.

In a C++ buffer post-command-hook has:

(global-font-lock-mode-check-buffers global-company-mode-check-buffers
global-hi-lock-mode-check-buffers winner-save-old-configurations
eldoc-schedule-timer mode-local-post-major-mode-change)

timer-list has:
Its value is ([nil 22100 46194 814488 3 quick-transfer-check-dired
      ("/home/hs/transfer/" 3)
      nil 945000]
 [nil 22100 46196 580496 nil undo-auto--boundary-timer nil nil 660000]
 [nil 22100 46207 130220 300 savehist-autosave nil nil 194000]
 [nil 22100 46240 0 60 display-time-event-handler nil nil 0])

(quick-transfer-check-dired self written to check a directory for new
content. This my colleague isn't running, s.b.)

timer-idle-list has:
([t 0 0 50000 t jit-lock-deferred-fontify nil idle 0]
 [t 0 0 100000 t mouse-avoidance-fancy nil idle 0]
 [t 0 0 125000 t show-paren-function nil idle 0]
 [nil 0 0 500000 nil
      #[0 "\b\204\x0f\0	\205\x11\0\n\303>?\205\x11\0\304 \207"
          [eldoc-mode global-eldoc-mode eldoc-documentation-function
                      (nil ignore)
                      eldoc-print-current-symbol-info]
          2]
      nil idle 0]
 [nil 0 0 500000 t which-func-update nil idle 0]
 [nil 0 0 500000 t jit-lock-context-fontify nil idle 0]
 [nil 0 0 500000 0.5 blink-cursor-start nil idle 0]
 [nil 0 1 0 t semantic-idle-scheduler-function nil idle 0]
 [nil 0 5 0 t jit-lock-stealth-fontify nil idle 0]
 [nil 0 10 560 nil jit-lock-stealth-fontify
      (t)
      idle 723000]
 [nil 0 60 0 t semantic-idle-scheduler-work-function nil idle 0])


> I think it's already been mentioned here:
> http://lists.gnu.org/archive/html/emacs-devel/2015-11/msg01655.html

Tried this patch. But I think I have seen it one time with this patch.

A Colleague mentioned that if he scrolls a (C++ containing) buffer to bottom
with pressing C-n (<down>) continously he saw the cursor jumping to
beginning of the buffer. But this also is not reproducible.

My guess it has to do with fontifying, perhaps jit-lock or semantic.


With kind regards,
Stefan

-- 
Stefan-W. Hahn                          It is easy to make things.
                                        It is hard to make things simple.