[MlMt] Messages in one account duplicated in some views, but not others

[Benny Kjær Nielsen]

On 17 May 2024, at 23:46, Eric A. Meyer wrote:

> On 17 May 2024, at 3:40, Benny Kjær Nielsen wrote:
>
>> Whenever seeing duplicates behaving like this, it's a good idea to enable the “Source Mailbox” column in the message list. It's very likely that the messages are not located in the same mailbox -- but somehow the server sees it as the same mailbox.
>
> They're in the same mailbox ("INBOX - eric at meyerweb.com").  Also they have the same UID, though not the same Msg ID.  Screenshot fragment I took just now: https://meyerweb.com/pix/2024/mailmate-dupes-source-uid-msgid.png

This does look like a MailMate bug and a pretty serious one. The Msg ID is the internal ID used by MailMate. This also tells us that MailMate has seen more than 2.6 million messages since you installed it. Although apparently some of those are duplicates. Duplicate Msg IDs in MailMate are not possible.

The UID is the server ID for each message. Each message in a specific IMAP mailbox has a unique UID. Duplicates are not possible.

> What's really frustrating from a reproducibility standpoint is that the duplication seems to have stopped happening.  Older duplicated messages are still duplicated, but new messages to the same mailbox are not.  Is it possible I somehow accidentally caused the mailbox to duplicate all its messages at some point without realizing it?

No, I think this is a MailMate issue. Somehow MailMate fetches the same message twice thinking they have different UIDs. I'm not sure how that could happen -- although some very old experimental features could be involved.

I think we should debug off list since I might need more details than should be shared on a public mailing list. I'll write you directly with some additional questions.

-- 
Benny