bug#52055: 29.0.50; emoji-insert garbles terminal display on tsdh-dark theme

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: bird <birdsite@airmail.cc>,  52055@debbugs.gnu.org
> Date: Tue, 23 Nov 2021 14:43:20 +0100
> 
> I'm wondering whether we should just disable the `C-x 8 e e' command on
> non-GUI -- it relies on presenting things in a tabular fashion, and we
> just don't have a way to interrogate the terminals about whether they
> support grapheme clusters like 🧏🏾 or not.

Would it work to display a single list on TTY frames, not two-column
list?

As for disabling: I'm not sure yet we should disable right away,
because it isn't clear to me how many terminals have such problems and
which problems can be solved.  We do know the type of the terminal, so
if there are simple enough solutions that produce reasonable display,
I'd hate denying those users the feature or parts thereof.

So I think we should collect data and possible solutions before we
decide.  (On the Linux console auto-composition-mode is already
disabled by default.)

> Or perhaps we should have a user option that disables all the emoji
> commands on non-graphical displays, and then people that know that their
> terminals support it can switch it on.  Because otherwise I think we're
> going to be getting a lot of these bug reports about this.
> 
> Or...  on non-graphical displays, the commands could say "These commands
> are likely to produce odd display results in most terminals; continue?"

Those are possible solutions, yes.  But I think we don't have enough
data yet to decide what's best.