[Mailman-Developers] In-Reply-To vs. References

[Aahz]

Harald Meland wrote:
>
> ... and before anyone gets religious on me here, I'll rush to explain
> that I _do_ see the harm of inserting "faulty" References: headers --
> any In-Reply-To: candidate should at the very least be in the form of
> a valid message ID.
> 
> I think there was a slightly similar discussion on the (ding) Gnus
> mailing list a while back -- it was spurred by the fact that Gnus'
> threading sometimes broke down, as some mailers put several
> message-id-look-a-like-tags (e.g. mail addresses in angle brackets) in
> their In-Reply-To: header.

Threading is already broken on the newsreader side if References: doesn't
exist.  I'd say that as long as it has the correct form, pass it on.  (I'm
also making the possible faulty assumption that the Gnus problem manifested
in the context of reading a mailing list rather than a newsgroup.)