IMAP hardcoded no object id into the message key, so it could only ever
reach the Message-ID+content tier or the folder-scoped surrogate, while
JMAP entered at the top tier from the server's Email id. One account
synced through both protocols therefore minted disjoint key spaces.
RFC 8474 EMAILID is the same identifier JMAP exposes, so requesting it
makes the two keys equal. Negotiate per capability: EMAILID only where
the server advertises OBJECTID, X-GM-MSGID only where it advertises
X-GM-EXT-1. A server offering neither behaves exactly as before.
EMAILID cannot go through the typed client: imap-proto's msg_att parser
is a closed alt with no catch-all, and async-imap turns the resulting
nom error into a fatal io::Error that closes the session. The raw layer
reads it off the transport beneath ImapStream instead, so an attribute
the crate cannot parse can never reach its decoder.
Lifting stored rows to a stronger tier changes every message_key, so
IDENTITY_SCHEMA_VERSION moves to 3 and the existing reconciliation
rebuilds the cached store rather than repointing rows one at a time.
james.maes
93f00cdd0b