mbsync stores UID in local maildir filenames, and assumes it is unique leading to invalid "duplicate UID" errors when moving files between folders

[epilys]

See more info here: http://web.archive.org/web/20240805063128/https://git.meli-email.org/meli/meli/issues/463/ | https://git.meli-email.org/meli/meli/issues/463

existing MUA workarounds

• mutt and mu4e:

  https://isync.sourceforge.io/mbsync.html#RECOMMENDATIONS

  When using the more efficient default UID mapping scheme, it is important that the MUA renames files when moving them between Maildir folders. Mutt always does that, while mu4e needs to be configured to do it:

  (setq mu4e-change-filenames-when-moving t)

• meli PR https://git.meli-email.org/meli/meli/pulls/464

[duesee]

Ouch... By the way: If I remember correctly, the UIDVALIDITY can also repeat, which then makes (mailbox, uidvalidity, uid) the only "truly" unique identifier for a message :-/