bug#73463: [PATCH] Align columns with wide characters properly

["Thomas Voss" via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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Hi all,

For a while I’ve been bugged by some behaviour in Which-Key.  My font of
choice is Iosevka — a font that is quite popular — and it chooses to make
the ellipsis character 2-columns wide.  This is typically not a problem,
but it causes Which-Key columns to appear misaligned as it truncates long
descriptions with the ellipsis by default when the user configures it to
use Unicode (and I rather enjoy the ellipsis).

This happens despite the following being in my init.el:

    (set-char-table-range char-width-table ?… 2)

After further investigation, this appears to be due to a simple usage of
‘length’ instead of ‘string-width’.  The following trivial patch attached
to this email seems to have solved this issue.

-- 
— Thomas

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From b87de8beb17582608afb7e9f30e67085c5d78d7a Mon Sep 17 00:00:00 2001
From: Thomas Voss <mail@thomasvoss.com>
Date: Wed, 25 Sep 2024 02:17:49 +0200
Subject: [PATCH] Align columns with wide characters properly
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In the case that a character in takes up multple columns (such as `…'
when used as a truncation character) make sure that the columns are
still aligned properly.
* lisp/which-key.el (which-key--pad-column):
Use `string-width' instead of `length'.

Copyright-paperwork-exempt: yes
---
 lisp/which-key.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/which-key.el b/lisp/which-key.el
index 91eb05c..fb0685c 100644
--- a/lisp/which-key.el
+++ b/lisp/which-key.el
@@ -2037,7 +2037,7 @@ that width."
           (mapcar (pcase-lambda (`(,key ,sep ,desc ,_doc))
                     (concat
                      (format col-format key sep desc)
-                     (make-string (- col-desc-width (length desc)) ?\s)))
+                     (make-string (- col-desc-width (string-width desc)) ?\s)))
                   col-keys))))
 
 (defun which-key--partition-list (n list)
-- 
2.46.1