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

[Stefan Monnier]

>>>     (global-auto-revert-mode 1)
>> Ha, I think you have your culprit right there: my crystal ball says that
>> if you have auto-revert active on the file you modify with
>> `write-region` (or maybe even just a file in the same directory) any
>> modification to the file (e.g. via `write-region`) will send
>> a pseudo-event, which Emacs's command-loop will confuse for an actual
>> user event!
> The problem being that until the 19th of December it worked without a
> problem. I did not change my .emacs.

And I see also that keyboard.c does seem to do it right:

      if (CONSP (c)
          && (EQ (XCAR (c), Qselect_window)
#ifdef HAVE_DBUS
              || EQ (XCAR (c), Qdbus_event)
#endif
#ifdef USE_FILE_NOTIFY
              || EQ (XCAR (c), Qfile_notify)
#endif
              || EQ (XCAR (c), Qconfig_changed_event))
          && !end_time)
        /* We stopped being idle for this event; undo that.  This
           prevents automatic window selection (under
           mouse-autoselect-window) from acting as a real input event, for
           example banishing the mouse under mouse-avoidance-mode.  */
        timer_resume_idle ();

Hmm...

> It is even more funny: when I play a video with mpv, idle time is also
> reset. And this I find really odd.

Can you try to run Emacs under GDB?
Then start Emacs to try and reproduce the problem with mpv.
Once ready to start mpv, hit `C-c C-z` in GDB, then type

    break timer_stop_idle
    continue

then launch mpv and try to see the backtrace (with command `bt`) when
the timer_stop_idle breakpoint is triggered.
[ Then again, maybe this will trigger all the time, but is a false
  alarm because it would be undone right after by the above code.  ]


        Stefan