Subject: Re: bug#42904: [PATCH] Non-Unicode frame title crashes Emacs on macOS

From: Eli Zaretskii <[email-masked]>
Date: Tue, 18 Aug 2020 15:22:11 +0300

> From: Mattias Engdegård <[email-masked]>
> Date: Tue, 18 Aug 2020 13:48:10 +0200
> Cc: Eli Zaretskii <[email-masked]>, [email-masked]
> 
> Anyway, here is an alternative patch using your method. Tell us what you think.

Thanks, but I don't think we should modify the :default-char attribute
of the UTF-* encodings as part of this change.  It's a separate issue,
and is a backward-incompatible change of sorts.  For instance, we
should consider what this will do to display on TTY frames that don't
support Unicode.  So I think we should discuss this issue separately
before we make such a change.

Why is it a problem to display a space instead of invalid bytes in
this case?