bug#56513: 28.1; Vcard in a mime part with a utf-8 charset is displayed incorrectly

[Roland Winkler <winkler@gnu.org>]

On Tue, Jul 12 2022, Lars Ingebrigtsen wrote:
>> FWIW buffer-file-coding-system in article buffer is iso-latin-1-dos.
>
> That's odd -- is vcard-pretty-print doing charset encoding?  What we're
> passing in should already be decoded (with that patch):
>
> +         (data (mm-decode-string (mm-get-part handle) charset))

Below I am re-posting an example of a vcard MIME attachment that Pascal
had originally posted on the BBDB mailing list.  The odd thing about
these MIME attachments is that vcard properties such as "org" and "adr"
in the example below may include "quoted-printable" paramaters as part
of the vcard itself.  So my understanding is that the decoding of the
quoted-printable encoded strings and any subsequent coding-system
decoding should be done by a vcard parser and not by a MUA when
processing MIME attachments.

The vCard format 4.0 (rfc6350) requires that vCards use utf-8, it does
not permit other coding-systems.  I do not know about earlier versions
of the vCard format.

,----
| Content-Type: text/x-vcard; charset=utf-8;
|  name="dupont.vcf"
| Content-Transfer-Encoding: 7bit
| Content-Disposition: attachment;
|  filename="dupont.vcf"
| 
| begin:vcard
| fn:Jean
| n:Dupont;Jean
| org;quoted-printable:Syst=C3=A8mes DUPONT
| adr;quoted-printable:BP X;;La Cit=C3=A9;Province;00000;France
| email;internet:dupont@systemes.fr
| title:Directeur
| tel;work:+33 (0)000000000
| tel;fax:+33 (0)111111111
| tel;cell:+33 (0)222222222
| url:http://www.dupont.fr
| version:2.1
| end:vcard
`----