bug#30080: 24.5; write-region can reset idle time

[Eli Zaretskii <eliz@gnu.org>]

> From: Cecil Westerhof <Cecil@decebal.nl>
> Cc: monnier@IRO.UMontreal.CA,  30080@debbugs.gnu.org
> Date: Fri, 12 Jan 2018 11:36:15 +0100
> 
> > desktop-save-mode writes the desktop file from time to time, and it
> > uses an idle timer, so I think this explains that.
> 
> I have two problems with that:
> - I do not think that it is done every minute, or less. And the reset
>   is done on the moment of the write-region of my command. So does not
>   directly relate to the writing of the desktop file.

desktop.el auto-saves when something in the window/buffer
configuration changes, no matter how frequently that happens.  The
idle timer run by desktop.el uses the same timeout value as auto-save,
which is 30 sec by default.  Maybe these facts will allow you to find
out why desktop-save-mode has that effect.

> - Before 19 December I did not have this behaviour. So it started
>   after an update. It did not work like this for more as five years,
>   but started the 19th of December 2017.

I guess you will have to find out what changed with that update.  No
one else except yourself can do that.  Maybe it's some change in the
kernel, or in glibc, or in inotify.

FWIW, I cannot reproduce your problem, neither in "emacs -Q" nor if I
turn on global-auto-revert-mode or desktop-save-mode, neither on
GNU/Linux nor on MS-Windows.  So this is most probably something
specific to your system.

What is the value of system-configuration-features in that build, btw?
Maybe some of the features is responsible for that, and my builds are
without it.