bug#60467: 30.0.50; primitive-undo: Changes to be undone by function different from announced

[Gregory Heytings]

> > Well, that bug was already discussed at length six months ago, and the 
> > minimal change that was in the end installed (59c3c53efa) introduced a 
> > new bug.  Should we design another minimal change, at the risk of 
> > introducing another bug?  ISTM that the safe thing to do is the 
> > refactoring that was suggested.
>
> If there's no safer way than the refactoring suggested back then, we 
> will have to stay with this regression in Emacs 29.1 and install a 
> better fix only on master.  After all, the fact that buffer-modified-p 
> is not undone is a minor inconvenience at best.

Indeed.  A safer way probably exists, but I would not dare writing that 
patch.  I believe Stefan is in a better position to write it.