bug#21722: 25.0.50; Unexpected point position after undo

[Markus Triska <triska@metalevel.at>]

In "emacs -Q", when I insert into *scratch* the form:

   (progn (end-of-line) (insert "\nhi"))

then place point on the "g" and press C-M-x C-/, then the insertion is
undone, and point remains on the "g", as expected. When I then press:

   C-h f C-g C-M-x C-/

the insertion is undone, and point is unexpectedly placed at the end of
the form instead of remaining on the "g". When I then place point on the
"g" again, and again press C-M-x C-/, point again stays on the "g".

Thus, point position after undo is sometimes unexpected.

For comparison: In Emacs 22.2, point remains on the "g" in all these
cases. This is more consistent, and, in my view, therefore preferable.


In GNU Emacs 25.0.50.5 (x86_64-apple-darwin14.1.0, X toolkit, Xaw3d scroll bars)
 of 2015-10-04
Repository revision: acfb5cd0353406784f085ddb6edfb0d0587048c8
Windowing system distributor 'The X.Org Foundation', version 11.0.11502000
Configured using:
 'configure --without-ns CFLAGS=-I/opt/local/include
 LDFLAGS=-L/opt/local/lib'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG IMAGEMAGICK GSETTINGS NOTIFY ACL GNUTLS
LIBXML2 FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS LUCID X11

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix