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

[Michael Heerdegen <michael_heerdegen@web.de>]

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.