Re: can undo unamalgamation be turned off reliably and completely?

[Samuel Wales <samologist@gmail.com>]

(setq undo-auto-current-boundary-timer t) does not work in my emacs 25
to turn off amalgamating.

however, i /might/ have thought of a solution.  called-interactively-p
does not work reliably with defadvice, but this-command-keys might be
a substitute.  then maybe i can advise all amalgamating commands, and
if nil, do undo-boundary.  untested.

and then when emacs 26 rolls around, i will try using (setq
amalgamating-undo-limit 1).  which i presume will work.  thank you for
all of your comments and, if any of you implemented turning off
amalgamation, for doing that too.


On 11/30/20, Michael Heerdegen <michael_heerdegen@web.de> wrote:
> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>
>> > If you set this variable to, say, t, that should turn off this feature.
>> > Should exist in 25.  May be named "undo-auto--current-boundary-timer"
>> > there.
>>
>> No, this part of undo was all hard coded in C in Emacs-25.
>
> I see the timer variable being introduced in Lisp with this commit:
>
> | 44dfa86b7d382b84564d68472da1448d08f48129
> | Author:     Phillip Lord <phillip.lord@newcastle.ac.uk>
> | AuthorDate: Thu Aug 6 21:33:58 2015 +0100
> | Commit:     Phillip Lord <phillip.lord@russet.org.uk>
> | CommitDate: Thu Nov 12 21:06:05 2015 +0000
> |
> | Parent:     0aec2aaccd * lisp/emacs-lisp/package.el: Simplify
> describe-package-1
> | Contained:  emacs-25 emacs-26 master
> | Follows:    emacs-24.5-rc3-fixed (5481)
> | Precedes:   emacs-25.0.90 (1955)
> |
> | The heuristic that Emacs uses to add an `undo-boundary' has been
> | reworked, as it interacts poorly with functions on `post-command-hook'
> | or `after-change-functions'.
>
> Am I interpreting the "Contained" and "Precedes" fields wrong?
>
>> It got rewritten in Elisp for Emacs-26, which indeed makes it possible to
>> change it much more easily.
>
> How would you deactivate it in versions not yet having the rewrite?
>
>
> Thanks,
>
> Michael.
>
>
>


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