[Dovecot] dsync is seriously broken when syncing maildir and mdbox

[interfaSys sàrl]

 Hello,

I thought mdbox was production ready, but it seems to me that (in 2.0.4)
it's quite broken.

1)  The documentation only running this to convert from maildir to mdbox:

*dsync mirror maildir:~/Maildir*

but based on my experience and on posts on the mailing list, it's not
enough.
A namespace has to be defined and it's not clear whether / or . should
be used as a separator.
I tried with a dot first and the INBOX folders were empty. It seemed to
work better with /

2) After having defined a namespace, running dsync again makes it spit
tons of errors
Error: Can't rename mailbox INBOX_28c716242e53784cc9030100d3b51c5c to
INBOX: Target mailbox already exists
Error: Mailboxes don't have unique GUIDs:
4536121fce3ca14cf8c40000d3b51c5c is shared by INBOX and
INBOX_4536121fce3ca14cf8c40c
Info: INBOX/spam: only in dest
Info: INBOX: only in source

Each run will create more folders with GUIDs attached to the folder name.

3) Deleting these folders after having moved their content to the
properly named ones seems impossible.
I see a long list of folders in the bin and when I hit "Empty bin" in
Thunderbird, nothing happens.
There must must be a caching issue, because if I click on the folder,
I'm told these folders don't exist.

If I dsync again, I still have conflicts, with folders that are in the
bin and then with new copies of INBOX
Error: Mailboxes don't have unique GUIDs:
4536121fce3ca14cf8c40000d3b51c5c is shared by INBOX and
Trash/INBOX_4536121fce3ca14c
Error: Mailboxes don't have unique GUIDs:
4536121fce3ca14cf8c40000d3b51c5c is shared by
INBOX_4536121fce3ca14cf8c40000d3b51c5c

At that stage, the newly created INBOXes cannot be deleted because they
already exist in the bin.

I renamed those folders, moved them to the bin, emptied the bin
And it's still not fixed when running dsync
Error: Mailboxes don't have unique GUIDs:
1a6f000a9751784c12030100d3b51c5c is shared by Sent and Trash/5
Info: Trash_INBOX_bb088f159336a14cc6bf0000d3b51c5c: only in dest
Error: Can't rename mailbox INBOX to Trash_3: Renaming INBOX isn't
supported.

Why can't folder properly be deleted? I never had that problem with Maildir.

Cheers,

Olivier