Subject: Re: bug#76852: 30.1; Regression in whitespace-mode causes display issue under terminal

From: 张海 <[email-masked]>
Date: Tue, 11 Mar 2025 21:56:00 -0700

> That rings a bell.  What happens if, before turning on whitespace-mode
> for the first time in a session, you customize the variable
> cjk-ambiguous-chars-are-wide to the nil value?  This must be done
> either via setopt or interactively via customize-option, not via setq.
> Does the problem go away if you do that, and then turn on
> global-whitespace-mode?

I can confirm this does make the issue go away.

But looking at the NEWS announcement for cjk-ambiguous-chars-are-wide,
it seems to suggest the previous default was already full-width, which
conflicts with the fact that whitespace-mode was working fine in
terminal in Emacs 29.4 under a CJK locale. So was there an
unintentional default behavior change, and should that be fixed?

> Can you look for a font where the characters U+00B7 MIDDLE DOT and
> U+00A4 CURRENCY SIGN have fullwidth glyphs?  I presume some
> CJK-specific fonts should be like that, since these characters are
> referred to as having "ambiguous width" in the Unicode character
> database.  If you can find such a font, please try setting up
> gnome-console to use it, and see if the problem then goes away.

No, the same issue persisted and the only difference is that this time
only the first half of the full-width middle dot was rendered.