Re: master 6b7ff60a5e7: Highlight the suffix in *Completions* buffer in 'basic' style too

[Eshel Yaron <me@eshelyaron.com>]

Hi Dmitry,

Dmitry Gutov <dgutov@yandex.ru> writes:

> branch: master
> commit 6b7ff60a5e71c161a064e27509fe4fb95cf74ddd
> Author: Dmitry Gutov <dmitry@gutov.dev>
> Commit: Dmitry Gutov <dmitry@gutov.dev>
>
>     Highlight the suffix in *Completions* buffer in 'basic' style too
>     
>     * lisp/minibuffer.el (completion-basic-all-completions):
>     Make sure to highlight the suffix as well (bug#71419).
> ---
>  lisp/minibuffer.el | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> 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 @@ Return the new suffix."
>                              '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)))

Note that unlike completion-hilit-commonality,
completion-pcm--hilit-commonality does not add the base size to the last
cdr of the result.  So this breaks e.g. file name completion:

1. emacs -Q in emacs.git checkout root directory
2. C-x C-f lisp/fo TAB
3. *Completions* pops up with some completion candidates
4. M-<down>

The minibuffer should now contain something like
~/checkouts/emacs/lisp/foldout.el but after this commit it instead
contains just foldout.el.

Something like the following should fix this issue:

diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 144cda8cfdc..0a0b17b3850 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -3816,7 +3816,9 @@ completion-basic-all-completions
                             'point
                             (substring afterpoint 0 (cdr bounds)))))
          (all (completion-pcm--all-completions prefix pattern table pred)))
-    (completion-pcm--hilit-commonality pattern all)))
+    (when all
+      (nconc (completion-pcm--hilit-commonality pattern all)
+             (car bounds)))))
 
 ;;; Partial-completion-mode style completion.