bug#45657: 27.1; Gnus: Non-ASCII characters garbled with 7bit and 8bit encoding

[Eli Zaretskii <eliz@gnu.org>]

> From: Justus-dev@Piater.name
> Date: Mon, 04 Jan 2021 18:17:51 +0100
> 
> Since Emacs 27.1 and still in the current development version, non-ASCII
> characters display incorrectly if the encoding is 7bit or 8bit, at least
> in my Gnus setup with nnmaildir backend.  This holds for both text/plain
> and text/html content types.
> 
> To test this, send yourself a MIME message such as the following:
> 
> <#multipart type=mixed>
> <#part type=text/plain charset="utf-8" encoding="7bit" disposition=inline>
> PUT SOME NON-ASCII CHARACTERS HERE
> <#part type=text/plain charset="utf-8" encoding="8bit" disposition=inline>
> PUT SOME NON-ASCII CHARACTERS HERE
> <#part type=text/plain charset="utf-8" encoding="quoted-printable" disposition=inline>
> PUT SOME NON-ASCII CHARACTERS HERE
> <#part type=text/plain charset="utf-8" encoding="base64" disposition=inline>
> PUT SOME NON-ASCII CHARACTERS HERE
> <#/multipart>
> 
> The first two parts will show non-ASCII characters in \ddd form (in HTML
> parts, this would be printable but wrong characters instead), while the
> third and fourth parts will display correctly.
> 
> I have not bothered reporting this till now because there is an easy
> workaround (hit e (to edit) followed immediately by C-c C-c (to commit
> the void edit), which will reencode the message in quoted-printable),
> and because I figured I cannot be the only one who observes this
> problem...???

Isn't this a duplicate of bug#44307?