Automatic content-type insertion

[Rob Mueller]

> > I'm just wondering why cyrus automatically adds a content type charset
to
> > every message, even if none is specified in the message itself. For
> > example:
> [...]
> > So there's no "Content-Type" line in the message, but the bodystructure
> > has given it an implicit charset of us-ascii. Now, I know that this is
> > technically true, but unfortunately, there seem to be quite a few broken
> > iso-2022-jp messages out there which don't actually specify the charset
in
> > the header. What we allow on our site is a 'default charset', which is
> > used if no charset is available, which would work fine in this
situation.
> > Unfortunately in this case, there's no indication that the ("CHARSET"
> > "us-ascii") response was auto-generated, rather than explicitly set.
>
> It does this because that's what the IMAP spec says to do. Section 7.4.2:
>
> >       BODYSTRUCTURE
> >          A parenthesized list that describes the [MIME-IMB] body
> >          structure of a message.  This is computed by the server by
> >          parsing the [MIME-IMB] header fields, defaulting various fields
> >          as necessary.
>
> > The main solutions I see are:
> > 1. Remove the implicit setting of the charset if none supplied

'defaulting various fields as necessary' seems an awfully broad statement.
Where does it specify which fields should be defaulted?

Rob