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

[Juri Linkov]

>> > 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
>> 
>> Actually, a change for base-suffix in minibuffer-completion-help
>> is a trivial change.  What counts as a non-trivial change would be
>> changing the API in completion-all-completions.
>> 
>> > 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.
>> 
>> These changes are specific to the M-<UP> and M-<DOWN> bindings:
>> completion-use-base-affixes is nil, and it's let-bound to t
>> in M-<UP> (minibuffer-previous-completion) and M-<DOWN>
>> (minibuffer-next-completion).
>
> The change I reviewed and to which I responded was in code that was
> there in Emacs 28 as well.  Maybe we are talking about two different
> sets of changes.

That code was added in Emacs 29 a year ago in the commit
7aaffe25eb178f69027fb0af844a89a86db4b1f2.