Re: [Jmap] Draft messages - mutability

[Neil Jenkins <[e-mail]>]

Yeh, a persistent identifier can certainly do much of the same job (in
theory the RFC5322 Message-Id should do this if you generate it in a
sensible way). And I agree that it simplifies sync code if all messages
are the same in terms of mutability (although I don't think it would be
too hard to support).
As Bron points out, you do have more work in the client to find the
message by the draft id, but given the above, and that this is also more
easily compatible with IMAP, I think sticking with the current immutable
model is probably better.
As Chris mentioned earlier, an atomic "replace" *would* be very helpful
for handling drafts. I actually think we can model this as a standard
JMAP update, just it returns a new id. So you would have something like:
[
    [ "setMessages", {
        "update": {
            "${currentMessageId}": {
                "to": [{
                    "name": "Joe Bloggs",
                    "email": "[e-mail]"
                }],
                ... all the other properties you normally pass to
                create ...            }
        }
    }, "tag" ]
]

which returns

[
    [ "messagesSet", {
        "updated": {
            "${currentMessageId}": {
                "id": "${newMessageId}"
            }
        }
    }, "tag" ]
]

Neil.