Jacob Palme <jpalme(_at_)dsv(_dot_)su(_dot_)se> writes:
If you resend a message as a body part with an added comment, this is
rather similar to writing a reply to that message, and in the case of a
reply, both are included in References.
I would say that if you resend a message with an added comment, you're not
resending, you're forwarding, and therefore you would not include Resent-*
headers and that case would be handled very differently.
I don't see a problem with including both message IDs in the case of
responding to a forwarded message (although most commonly software will
refer to only the message ID of the forwarded message since the forward
operation normally doesn't construct a References header), but I don't
think the case of a forwarded message with additional comments is
equivalent to a resent message.
Resending is intended to be more "invisible" to mail semantics,
retroactively adding additional recipients to the message, and I think the
construction of the References header should follow that principle.
--
Russ Allbery (rra(_at_)stanford(_dot_)edu)
<http://www.eyrie.org/~eagle/>