[Dovecot] IMAP folders sort order

[Michael M Slusarz]

Quoting "Valery V. Sedletski" <valerius at afterlogic.com>:

>>>
>>> But I tried to create a fresh account in Dovecot (not migrated from
>>> Courier), and it
>>> still shows a intermixed folder order:
>>>
>>> a list "" *
>>> * LIST (\HasNoChildren) "/" "Spam"
>>> * LIST (\HasNoChildren) "/" "Sent"
>>> * LIST (\HasNoChildren) "/" "Drafts"
>>> * LIST (\HasNoChildren) "/" "Trash"
>>> * LIST (\HasNoChildren) "/" "INBOX"
>>> * LIST (\HasNoChildren) "/" "Pub"
>>> a OK List completed.
>>
>> Why does this matter?  IMAP does NOT enforce any sort of required
>> sorting order, and no IMAP client can assume a sort order.  So
>> enforcing a sort order on the server is just a waste of resources.
>>
>
> Just a cosmetic problem, of course. Some IMAP clients do sort folders,
> others do not, so they show different folder sort order in Dovecot, if
> migrated from Courier (Courier seems to sort folders, so that the system
> ones appear first). We just needed a seamless migration.

Still don't see the relevance to a migration though.  If you have  
software that assumes that mailboxes are listed in some sort of order,  
that is just broken software.

>> FWIW, this is completely legal IMAP output also (albeit inefficient):
>>
>> a list "" *
>> * LIST (\HasNoChildren) "/" "Spam"
>> * LIST (\HasNoChildren) "/" "Sent"
>> * LIST (\HasNoChildren) "/" "Spam"
>> * LIST (\HasNoChildren) "/" "Spam"
>> * LIST (\HasNoChildren) "/" "Drafts"
>> * LIST (\HasNoChildren) "/" "Trash"
>> * LIST (\HasNoChildren) "/" "Spam"
>> * LIST (\HasNoChildren) "/" "Spam"
>> * LIST (\HasNoChildren) "/" "Spam"
>> * LIST (\HasNoChildren) "/" "Spam"
>> * LIST (\HasNoChildren) "/" "INBOX"
>> * LIST (\HasNoChildren) "/" "Pub"
>> a OK List completed.
>>
>
> So, it is legal to even list each folder several times?

Sure.  Just like this is legal IMAP:

a FETCH 1 (UID)
* 2 FETCH (UID 100)
* 3 FETCH (FLAGS (\Seen))
* 1 FETCH (UID 50)
* 1 FETCH (UID 50)
* 1 FETCH (UID 50)
* 2 FETCH (UID 100)
a OK FETCH complete

Once again: not efficient, but perfectly acceptable.

michael