mbnames is initialized and written once in the run from OfflineImap.__sync().
However, the in-memory instance is fed with data at sync time for each folder
and the intermediate files are written as soon as all the folders are synced for
the account. All of this is done inside the SyncableAccount.__sync() method
while the syncrunner is looping on this.
This means that we duplicate entries for mbnames in each loop (most likely when
autorefresh is enabled).
It is wrong to have duplicates in mbnames for each account. Ignore duplicates
when adding data in the mbnames intermediate files.
Github-ref: https://github.com/OfflineIMAP/offlineimap/issues/467
Reported-and-tested-by: Shin Kojima <shin@kojima.org>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>
5d5ad62fa7