bug#15567: Point jumps around madly in XML file when undoing while auto-revert-mode updates buffer

[Stefan Monnier]

> shortly point jumps to a wrong part of the buffer. If I wait, it jumps
> back and forth every second or two between where I wanted to be and
> elsewhere in the buffer. I ended up killing the buffer and revisiting
> the file to get back to something usable.

> I have been running Emacs with debug statements to walk the specpdl
> stack during redisplay and look for save_excursion_restore markers
> that mismatch current marker at redisplay. See
> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=15045#29 for why and the
> debugging patch. I was spammed with this output:

Thank you very much, this backtrace is very welcome.  Haven't looked at
how best to fix the problem, but at least the problem is clear.


        Stefan