Some emojis aren't rendered with recent Kitty versions

[xfzv]

Problem

Starting with Kitty 0.33.1 (I didn't try 0.33.0 because the ebuild is no longer available in Gentoo repositories but considering the changelog, I guess it might have started with 0.33.0), some emojis are no longer rendered.

According to Kitty maintainer, this isn't an issue with Kitty but with Vim/Neovim. Downgrading Kitty to 0.32.1 solves the issue for me. I cannot reproduce with WezTerm (x11-terms/wezterm-20240203.110809-r1 from Gentoo repositories).

Equivalent bug report in Vim repository, although I couldn't reproduce with vim 9.0.2167 on my end.

Occurs with both 0.9.5 and 0.10 here, as long as I'm using Kitty >=0.32.1:

% nvim -v
NVIM v0.9.5

% nvim -v
NVIM v0.10.0-dev-3121+ge3ec97432-dirty

Steps to reproduce

1. Add some emojis to a text file:

:arrow_up:
:arrow_left:
:arrow_down:
:arrow_right:
:arrow_up_small:
:arrow_double_up:
:arrow_up_down:
:arrow_forward:
:arrows_clockwise:
:arrow_down_small:
:arrow_double_down:
:arrow_backward:
:arrow_upper_left:
:arrow_lower_left:
:arrow_right_hook:
:arrow_heading_up:
:arrow_upper_right:
:arrow_lower_right:
:arrow_heading_down:

⬆️
⬅️
⬇️
➡️
🔼
⏫
↕️
▶️
🔃
🔽
⏬
◀️
↖️
↙️
↪️
⤴️
↗️
↘️
⤵️

2. Open the file with:

% nvim --clean a.txt

• With Kitty 0.32.2, all emojis are rendered:
  

• With Kitty 0.34.1, only some emojis aren't rendered:
  

I used some emojis starting with "a" for demonstration purpose but many other emojis are not rendered with 0.34.1.

Expected behavior

All emojis are rendered with Kitty >=0.32.1

Neovim version (nvim -v)

NVIM v0.10.0-dev-3121+ge3ec97432-dirty Build type: Release LuaJIT 2.1.0-beta3 Run "nvim -V1 -v" for more info

Vim (not Nvim) behaves the same?

no, 9.0.2167

Operating system/version

Gentoo

Terminal name/version

kitty 0.34.1

$TERM environment variable

xterm-kitty

Installation

from Gentoo repositories (app-editors/neovim)

[zeertzjq]

Duplicate of #7151