narrow character + emoji variation results in wrong(?) width (displays incorrectly in kitty)

[ces42]

Steps to reproduce

The developer of kitty has some insight into this issue: kovidgoyal/kitty#7329 (comment)

1. write just "⚠️" into a text file
2. run vim --clean file.txt in any terminal emulator -- everything looks fine, but vim will treat the character as single-width, so it might visually overlap with the next character
3. run vim --clean -c 'set cursorline | hi CursorLine cterm=none' file.txt in a very recent version of Kitty (e.g. 34.0) - The character is not rendered (you can tell there's a character in the file by moving the cursor and such, but it's "invisible")

Expected behaviour

the contents of the file are displayed correctly

Version of Vim

VIM - Vi IMproved 9.0 (2022 Jun 28, compiled Mar 14 2024 13:39:48) Included patches: 1-1672, 1729, 1747, 2107, 1840, 1846-1848, 1857-1858, 1873, 1969, 1992, 2010, 2068, 2106, 2108-2112, 2121

Environment

Ubuntu 23.10, zsh, kitty

Logs and stack traces

No response

[ronin49]

doesn't reproduce in suckless terminal