duplicity Exclude Globbing ** Asterisk not working as expected

Question

I try to backup all Maildir of all users with duplicity. But for some reason it excludes the largest one. Some background information:

• /Users/userA/Maildir has >5GB in Maildir
• /Users/userB/Maildir has <10MB in Maildir
• /Users/userC/Maildir has <10MB in Maildir
• /Users/userD/Maildir has <10MB in Maildir

If I run this command (same problem without --dry-run, it just shows the issue faster):

duplicity --dry-run --encrypt-key AAAABBBB --include '/Users/*/Maildir' --exclude '**' /Users sftp://USER@SERVER//private-backup/BACKUPFOLDER/

it would exclude all files of the largest user in /Users/userA/Maildir as you can see it considers only 24.8 MB. All other users are included in the backup if I list-current-files afterwards running not as --dry-run

--------------[ Sicherungsstatistiken ]--------------
StartTime 1576227515.48 (Fri Dec 13 09:58:35 2019)
EndTime 1576227515.63 (Fri Dec 13 09:58:35 2019)
ElapsedTime 0.15 (0.15 seconds)
SourceFiles 670
SourceFileSize 26000373 (24.8 MB)
NewFiles 382
NewFileSize 26000373 (24.8 MB)
DeletedFiles 0
ChangedFiles 0
ChangedFileSize 0 (0 bytes)
ChangedDeltaSize 0 (0 bytes)
DeltaEntries 382
RawDeltaSize 0 (0 bytes)
TotalDestinationSizeChange 0 (0 bytes)
Errors 0
-----------------------------------------------------

however if I change the source from /Users to /Users/userA/Maildir it would backup all mails of UserA but (of course) not for the others:

duplicity --dry-run --encrypt-key AAAABBBB --include '/Users/*/Maildir' --exclude '**' /Users/userA/Maildir sftp://USER@SERVER//private-backup/BACKUPFOLDER/

--------------[ Sicherungsstatistiken ]--------------
StartTime 1576227552.38 (Fri Dec 13 09:59:12 2019)
EndTime 1576227563.13 (Fri Dec 13 09:59:23 2019)
ElapsedTime 10.74 (10.74 seconds)
SourceFiles 69940
SourceFileSize 6268572008 (5.84 GB)
NewFiles 34988
NewFileSize 6268572008 (5.84 GB)
DeletedFiles 0
ChangedFiles 0
ChangedFileSize 0 (0 bytes)
ChangedDeltaSize 0 (0 bytes)
DeltaEntries 34988
RawDeltaSize 0 (0 bytes)
TotalDestinationSizeChange 0 (0 bytes)
Errors 0
-----------------------------------------------------

So what could be wrong here? Any help is much appreciated!

Answer 1

I searched the internet for hours, and finally found the embarrassing solution by coincidence on my own:

The Maildir (for what reason ever) has a capital D MailDir in the folder for the UserA.