I've been trying to diagnose some strange interaction between dovecot and Mozilla Thunderbird.

If two clients are connected to a dovecot IMAP server, Mozilla-based clients start showing multiple messages in the message list for each message that arrives after the sessions were started.

There is really only one copy of the message in the mbox file on the server. However, its UID changes repeatedly during the session, and Mozilla gets confused. From looking at Thunderbird's log of the IMAP conversation, it seems the message sequence number does not change, and I'm guessing that other clients handle the situation better because of this.

Nevertheless, I found this in the IMAP RFC 3501, so my interpretation is that there is a dovecot bug involved:

The unique identifier of a message MUST NOT change during the session, and SHOULD NOT change between sessions. Any change of unique identifiers between sessions MUST be detectable using the UIDVALIDITY mechanism discussed below. Persistent unique identifiers are required for a client to resynchronize its state from a previous session with the server (e.g., disconnected or offline access clients); this is discussed further in [IMAP-DISC].

Has anyone else experienced this problem? Is there a known solution?

I've been logging what I've found so far at http://bugzilla.mozilla.org/show_bug.cgi?id=209561

-- Matt

Funky like your grandpa's drawers