ElyOffice/tasks/reviews/C12.7-r1.md

FAIL

• crates/ely-mail-engine/src/sync.rs:111 — UIDL deduplication uses only the pre-sync held snapshot; successfully downloaded UIDLs are never added. A server can legitimately list 1 aa1 and 2 aa1 for identical copies (RFC 1939 §7). Starting with an empty inbox, both messages are retrieved and written, although they have one UIDL and produce one local message. The isolated regression reproduced two RETR commands and report.bodies == 2 instead of 1 (.work/c12.7-r1-probe.log). This violates C12.7's download-once requirement and can unnecessarily fail synchronization if the redundant transfer fails. Add each UIDL to the current session's set after its local write succeeds; still issue DELE for every server message number when keep is false. Cover duplicate UIDLs within one listing in both retention modes.