bug#71419: 30.0.50; Completion does not always highlight the "common part" corresponding to suffix

[Dmitry Gutov]

On 10/06/2024 00:06, Stefan Monnier wrote:
> > diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
> > index f62cb2566b2..144cda8cfdc 100644
> > --- a/lisp/minibuffer.el
> > +++ b/lisp/minibuffer.el
> > @@ -3816,7 +3816,7 @@ completion-basic-all-completions
> >                               'point
> >                               (substring afterpoint 0 (cdr bounds)))))
> >            (all (completion-pcm--all-completions prefix pattern table pred)))
> > -    (completion-hilit-commonality all point (car bounds))))
> > +    (completion-pcm--hilit-commonality pattern all)))
> >
> >   ;;; Partial-completion-mode style completion.
>
> Thanks for tracking it down.  It matches my expectation.

Thanks, now fixed on master.

> > But it would have been nice to be able to use it in the "progressive
> >   improvement" kind of fashion: when the suffix and the other parts are
> >   highlighted correctly, we do the right thing; if the style missed the
> >   suffix highlighting, we do the other thing - and put the responsibility on
> > the third party.
>
> 🙂

It could work like in the attached. I agree that it's somewhat brittle, 
though.

If you're not in favor of installing this patch, what would be your 
preferred strategy for fixing bug#70968? We could try resurrecting the 
relevant part of Daniel's patch for completion-all-completions, but it 
means a fair amount of breakage. Or another dynamic variable similar to 
completion-lazy-hilit-fn...

FWIW my interest here is how to better implement the same step in 
company-mode, but the default UI is a good common ground.

completions--count-common-spans.diff
Description: Text Data