Subject: bug#23785: Emacs 25: "Undo" overdoes things.

From: Alan Mackenzie <[email-masked]>
Date: Sat, 18 Jun 2016 17:41:36 +0000

Hello, Phil.

On Fri, Jun 17, 2016 at 10:23:51PM +0100, Phillip Lord wrote:
> Alan Mackenzie <[email-masked]> writes:

> > I don't think it's all that minor an issue.  `undo' can no longer be
> > depended upon to restore a buffer to its unchanged state.

> > I've suffered several similar annoyances with `undo' in the emacs-25
> > branch.

> If you report them, then I will look at them, and I would appreciate if
> you do report them.

For example, at times I've deleted a character, moved point, then deleted
another character.  Undo has undone both deletions as a single operation,
despite the point movement between them.

> I changed undo in a way that *was* supposed to change its semantics,
> and this may have had negative side effects. Or my changes may have
> caused unexpected changes in semantics that I did not intend.

The lack of configurability seems to be a problem.  There have been
times, testing times, when I've felt that each deletion of a character is
its own atomic operation.  Yet I can't configure undo to respect this
wish.

[ .... ]

> I will investigate.

> Phil

-- 
Alan Mackenzie (Nuremberg, Germany).