On Fri, Apr 25, 2025 at 10:58 AM Ship Mints <shipmints@gmail.com> wrote:
On Fri, Apr 25, 2025 at 9:51 AM Ship Mints <shipmints@gmail.com> wrote:
On Sun, Apr 13, 2025 at 5:52 AM Eli Zaretskii <eliz@gnu.org> wrote:
> From: Ship Mints <shipmints@gmail.com>
> Date: Fri, 11 Apr 2025 11:32:18 -0400
>
> -Q reproducer
>
> ;; The culprit appears to be `redisplay--update-cursor-face-highlight'
> (setq debug-on-error t)
> (cursor-face-highlight-mode)
> (save-excursion (insert (propertize "cursor face text\n"
>                                     'cursor-face 'region)))
> (narrow-to-region (pos-bol) (pos-eol))
> (setq unread-command-events (mapcar #'identity
>                                     (kbd "C-n")))

Thanks, does the below fix it?

diff --git a/lisp/simple.el b/lisp/simple.el
index ee09a6f..9e9dd15 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -7265,7 +7265,7 @@ redisplay--update-cursor-face-highlight
               (pt (window-point window))
               (cursor-face (get-text-property pt 'cursor-face)))
         (let* ((start (previous-single-property-change
-                       (1+ pt) 'cursor-face nil (point-min)))
+                       (min (1+ pt) (point-min)) 'cursor-face nil (point-min)))
                (end (next-single-property-change
                      pt 'cursor-face nil (point-max)))
                (new (redisplay--highlight-overlay-function

Eli, possible to apply the above soon?

Actually, I'm back to thinking this is better or the effect is that the whole buffer can wind up being unexpectedly highlighted:

                       (min (1+ pt) (pos-bol)) 'cursor-face nil (point-min)))

To be clearer:

The original condition (1+ pt) 'cursor-face nil (point-min))) works fine in a wide buffer.

The condition (min (1+ pt) (point-min)) 'cursor-face nil (point-min))) in a wide buffer winds up highlighting all the way to point-min in a buffer where every line has 'cursor-face which is undesirable.

I've experimented and tried to have 'cursor-face span only bol to eol-2 and that is confirmed visually, yet the entire buffer before the current line is highlighted in the cursor face.

mouse-face highlighting on the same lines (the text properties are applied all together) works properly whether the buffer is narrowed or wide.

I suppose it's technically doing the correct thing if every single line in a buffer has a cursor-face property?  How does one differentiate one line from another, if so, and why does mouse-face work differently?