bug#50865: 28.0.50; Emoji with emoji modifier in Linux console garbles emacs display

[Aura Kelloniemi]

On 2021-10-01 at 16:35 +0300, Eli Zaretskii <eliz@gnu.org> wrote:
 > > From: Aura Kelloniemi <kaura.dev@sange.fi>
 > > Cc: 50865@debbugs.gnu.org
 > > Date: Fri, 01 Oct 2021 16:23:01 +0300
[--]
 > > Here is a sample Bash session for demonstration:
 > > $ echo $'i\u300'
 > > i◈
 > > $ echo $'\uEC'
 > > ì

 > Ouch!  What a terrible misfeature!

Yes, but of course unintentional.

Variation selectors work in a similar way. <HEAVY BLACK HEART> <VARIATION
SELECTOR-16> prints two diamonds which is two 1-column wide characters.

There has been a recent change in emacs after which it no more prints the
variation selectors. This is probably related to the addition of
glyphless-char-display-control.

Anyway, with Linux it is safest to think the console as an old text-mode VGA
display which has been extended to support more codepoitns.

 > Does term/linux.el get loaded when you run Emacs on that terminal?

Yes. GNU/Linux distros are configured to set TERM=linux at latest in the
console getty processes.

-- 
Aura