bug#64300: 28.2; Can no longer input some tokens.

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Christian Brolin <cbrolin@gmail.com> writes:

> Hi, sorry for late reply.
>
> I'm currently using:
> GNU Emacs 28.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.37,
> cairo version 1.16.0)
>  of 2023-03-16, modified by Debian
>
> I don't know how to find out my previous version, but since I accept
> updates regularly, I guess it was the latest Debian build before Jun
> 26.

Thanks.  Then I guess it's unrelated to the misguided attempts to
work-around a bug in the Xlib XIM implementation that were installed in
Emacs 28.

> The problem still persist, but now I found out, only when I start
> Emacs from the main menu, not when I start it from a terminal, so
> maybe some problem with the environment. I tried to add LANG=C.UTF-8
> to the menu entry which helped! So this is no longer an issue for
> me. But I still get the gray Pop-up somewhere on the screen when I
> press a modifier, e.g. ~ until I press the second key. I don't
> remember to have seen this before, is this a new feature? And if so,
> maybe it is related to this issue. But the important thing is that I
> now can use Emacs again.

Xlib needs the system locale to be correctly defined in order to
negotiate text encodings with the input method.  Emacs also needs to see
a valid `locale-coding-system' in order to decode keyboard input.

In order to rule out any chance of this being a bug in Emacs, would you
please reply with the values of the environment variables $XMODIFIERS,
$LANG, and that of `locale-coding-system', in an Emacs session run
without any modifications to the menu entry?

TIA.