rfc: improved MIME handling (multipart)

[David Edmondson]

On Fri, 29 Oct 2010 16:58:45 -0700, Carl Worth <cworth at cworth.org> wrote:
> On Mon, 10 May 2010 11:33:03 +0100, David Edmondson <dme at dme.org> wrote:
> > A (third) attempt at improved MIME handling, specifically for multipart,
> > is at:
> >    http://github.com/dme/notmuch/tree/mp3
> >    git://github.com/dme/notmuch.git (branch 'mp3')
> 
> Hi David,
> 
> I went to pull this, but I couldn't find satisfactory commit
> messages. Things like "multipart: Fix part counting" aren't descriptive
> enough for me. What was broken? How was it fixed?

I was genuinely asking for comments rather than suggesting that those
changes get committed as-is (although they do work). See more below.

> A good test for a bug-fix commit message is "Could a reasonable person
> (skilled in the art) read my commit message and confidently create a
> test case for my fix?". If not, please add more detail.

Understood and agreed.

To improve the treatment of multipart/* messages in the emacs interface
it's necessary to expose more of the underlying structure of the
messages than is currently available. This affects mostly the JSON
formatted output, though I expect that some of the other formats may
also see small changes.

I'd like some guidance and/or feedback on a way to do that which is
likely to be acceptable. The previous attempt is most concisely
described by this change:

  https://github.com/dme/notmuch/commit/2268fee48e7295519cabfd6bcb8a7aa2f8817401

though that is now obviously out of date (as well as requiring a couple
of follow-on fixes and consequent changes). It is also quite messy.