bug#23871: 25.1.50; Undo unexpectedly leads to blank buffer

[Markus Triska <triska@metalevel.at>]

Hi Phillip,

phillip.lord@russet.org.uk (Phillip Lord) writes:

> I have pushed this to emacs-25, since Eli was happy with the last
> version, and you're happy with this.

One issue I noticed with the current undo system is that it behaves
differently if the command that inserts text is invoked via a keyboard
shortcut instead of via M-x ... RET.

For example, in the recipe I gave, if you invoke Emacs via:

   $ emacs -Q ceiled.pl -fn "Bitstream Vera Sans Mono 15" \
       --eval "(progn (load \"$PWD/ediprolog.el\") \
                      (global-set-key [f9] 'ediprolog-dwim))"

(note the use of F9 as a shortcut for ediprolog-dwim), and then press F9
instead of M-x ediprolog-dwim RET to invoke the query, then, after undo,
point is placed at the *beginning* of line 15 instead of at the end.

In fact, I find the former behaviour desirable since it puts point
exactly where it was before the whole insertion started, and I hope that
this can also be adopted if the command is invoked with M-x ... RET.

All the best,
Markus