bug#62700: 29.0.60; minibuffer-{previous,next,choose}-completion behave unintuitively when point is not at end of buffer

[Eli Zaretskii]

> From: sbaugh@catern.com
> Date: Sat, 08 Apr 2023 10:58:36 +0000 (UTC)
> Cc: 62700@debbugs.gnu.org, sbaugh@janestreet.com, juri@linkov.net
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> >
> > If this is for master, I'm fine with such changes.  But if you intend
> > to request installing this on emacs-29, then I will object making
> > non-trivial changes in any code that is not specific to the M-<UP> and
> > M-<DOWN> bindings that are new in Emacs 29.  I don't want to risk any
> > regressions in general-purpose completion code at this late stage.
> 
> OK, that's no problem, this can be done by just let-binding
> completion-base-affixes in minibuffer-{previous,next,choose}-completion
> so that it only affects new code.

Thanks.

> That will be a bit uglier to read so I'll do that if this approach
> seems reasonable with some review.

We can install the cleaner change on master, and the "uglier" one only
on the release branch.