bug#31588: 26.1; format counts some Unicode characters as two

[Noam Postavsky]

"James P. Ascher" <jpa4q@virginia.edu> writes:

> 3: M-S-: and call (insert (format "%-2s" '➖))
>
> What I expected:
>
> xxxxx➖ xxxxxxxx
>
> What results:
>
> xxxxxx➖xxxxxxx
>
>
> In comparison, (insert (format "%-2s" 'z)) gives:
>
> xxxxxxz xxxxxx

> The same problem occurs on my setup with ❌ (CROSS MARK).
>
> However, these Unicode items characters work as I expect: ▶ (BLACK
> RIGHT-POINTING TRIANGLE), ✚ (HEAVY GREEK CROSS), ▷ (WHITE RIGHT-POINTING
> TRIANGLE), and ◼ (BLACK MEDIUM SQUARE).
>
> As far as I can tell, something is off about the styled_format and how
> it counts characters- I suspect something about counting
> multibyte characters, but it's a little beyond me.

I think it's intended, ➖ and ❌ are wide characters:

    (mapcar #'char-width '(?➖ ?❌ ?▶ ?✚ ?▷ ?◼))
    ;=> (2 2 1 1 1 1)

Although in my current font the width seems to be more like 1.8 or
something.

wide-chars.png
Description: screenshot of the characters