Bug?: notmuch-search-show-thread shows several threads; only one containing matching messages

[David Bremner]

Mark Walters <markwalters1009 at gmail.com> writes:

>
> I have looked at this and I think this is not notmuch's fault: I think
> it is a mua doing strange things:
>
> One of the mails has an in-reply-to header which looks like
>
> In-reply-to: Message from Carsten Dominik <carsten.dominik at gmail.com> of        "Tue, 15 Mar 2011 12:18:51 BST."        <17242340-A14F-495A-B144-20C96D52B620 at gmail.com>
>
> and I think notmuch is taking the carsten.dominik at gmail.com as message
> id.
>
> A similar in-reply-to header appears in the other thread so notmuch
> pairs them up. According to http://www.jwz.org/doc/threading.html this
> form of header is not allowed under RFC2822 but was allowed under the
> earlier RFC822.

I have identified a second, similar problem. Some MUA insert(s|ed) the
From: address into the References field.

For an example see

  id:t2sfa09ca6d1004220920haccb86aam4bb949c77024c6e6 at mail.gmail.com
  https://www.mail-archive.com/emacs-orgmode@gnu.org/msg24266.html
  
This seems to be another throwback to rfc822

I don't know how notmuch can detect this once it those references
propagate to replies.

- we could merge threads only based on messages known to exist (ignoring
  ghost messages), but presumably there's a reason we invented ghost
  messages

- we could, at some point in future support blacklisting references
  (using message properties).