[RFC] 'bzr-email' using revision_id for threading

[Stephen J. Turnbull]

Robert Collins writes:

 > As I read the spec, if both launchpad, you, and I all generate an
 > announce email for a given revid, we must use unique message ids.

Spec doesn't say that.  For example, if the "important content" of the
message is that (a) a new commit has been added and (b) it can be
found in "the usual places" with the given revid, and all the users
agree that is true, it's ok to have multiple textually different
messages with the same Message-ID.

One way to think about it is that any text you personally add will be
treated like those annoying prefixes before the body parts of a MIME
message.

This might be a good thing.

OTOH, disambiguating who sent it is simple enough:

    Message-ID: <REVID at USER.ORGANIZATION.DOM>

where you simply substitute a dot for an at-sign in USER's email
address.  If you want to have message IDs that thread rather than
shadow each other,

    Message-ID: <REVID.UNIQUIFIER at USERID.ORGANIZATION.DOM>

Yet another way to look at it: prepend the REVID to your usual UUID
message-ids.  If the UUID is any good, REVID.UUID should still be a
UUID, but now the message ID contains parsable content.