bug#61535: 29.0.60; choose-completion erases in-region buffer

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 61535@debbugs.gnu.org
> Date: Thu, 16 Feb 2023 19:51:05 +0200
> 
> >> 1. type: (with-c C-M-i
> >> 2. type: M-down ... M-RET
> >> 3. check that the whole buffer was deleted before a selected
> >>    completion candidate was inserted to the buffer:
> >>    C-h v buffer-undo-list RET
> >
> > Which buffer was deleted? *scratch*?  It isn't here.
> >
> > And what does "C-h v buffer-undo-list RET" mean?
> >
> > Bottom line: I don't understand what is the bug here and/or how to
> > reproduce it.
> 
> The contents of the *scratch* buffer is erased and replaced
> with the same text.  This fact can be confirmed by looking
> at the value of 'buffer-undo-list' that contains the text
> of the whole buffer as a string.  Especially this is noticeable
> when using in-region completion in a large buffer.
> 
> With the patch, only the completed string is inserted.

Thanks for the explanation.  Then please install this on master, since
AFAIU this is a very old problem, and it's just an aesthetic one.