> I see no Emacs problem here

But the problem does not happen with vim (nor with emacs 27 for
`weird.txt`), so it is clearly an interaction of different elements.

Anyhow, I have opened an [upstream issue](
https://github.com/kovidgoyal/kitty/issues/4094). Please subscribe to it so
that you might offer your emacs expertise there, if needed.

> changing the "character encoding" setting in iTerm to ASCII

This is a most loath workaround. I do want UTF-8, as I use mathematical
symbols, emojis, and non-English languages. Anyhow, making the text full of
random unrecognized characters is not much better than the current behavior.

On Sun, Oct 3, 2021 at 2:42 PM Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Rudi C <rudiwillalwaysloveyou@gmail.com>
> > Date: Sun, 3 Oct 2021 14:30:56 +0330
> >
> > Also, can you be more specific about where you do observe the bugs? In
> TUI emacs on iTerm?
> >
> > I can confirm that the bug with `weird.txt` happens on iTerm, too, again
> with both emacs and neovim! But the
> > bug with `bug.txt` does not happen in iTerm, only on Kitty.
>
> This sounds like the terminal emulators have a problem in supporting
> unusual Unicode characters, such as zero-width or double-width
> characters, perhaps?  I see no Emacs problem here, since it happens
> only on some terminal emulators and not on others.
>