>>>>> Sven Joachim wrote:

> I have a problem with the gnus-mime-view-part-as-charset command that
> only shows up in Emacs 23, not sure whether this is a bug in Emacs or in
> Gnus.

> If an article has attachment with a wrongly specified charset, Gnus can
> work around that with the gnus-mime-view-part-as-charset command.  For
> instance, <news:20080908175652.GF4996@firemoth> on
> gmane.linux.debian.internationalization.german aka
> debian-l10n-german@lists.debian.org is such an article, it has an
> attachment that is incorrectly described as "Content-Type: text/x-diff;
> charset=utf-8" while it's actually encoded as iso-latin-1.  Now when I
> press C RET iso-latin-1, Emacs displays the German umlauts as octal
> sequences.  In Emacs 22.3, they are displayed correctly (Gnus version is
> the same, current No Gnus CVS).

That's exactly a bug.  Even in Emacs 22.3, it is not displayed
correctly if attachment contains CJK characters with wrong charset.
The patch is below.  I'll commit this after testing it further.