Re: [lemonade] Query regarding RFC4551

[Jan Kundrát <[e-mail]>]

On Friday, 4 April 2014 16:39:38 CEST, Jayantheesh S B wrote:
> Enabling the CONDSTORE feature based on the CAPABILITY is right 
> implementation

If you see CONDSTORE in the capability list, you know that the server 
understands these commands and therefore "supports" the extension. However, 
some servers might be operated in a degraded mode where they choose not to 
offer the CONDSTORE functionality for some of the exported mailboxes -- 
perhaps deliberately, perhaps due to some operator error. It's possible 
that the e-mails are stored on punch cards and there is no space to punch 
enough holes for the HIGHESTMODSEQ on the card which repreents a mailbox, 
for example. Or maybe your client is talking to an IMAP proxy which exports 
data from an ancient server which was released back when CONDSTORE was 
still in the womb. Either way, your client cannot effectively use any 
benefits that CONDSTORE brings within that particular connection to that 
mailbox. It's also possible that the next SELECT will return a MODSEQ, 
that's also allowed by the spec.

> As well, I would like to know, this commercial IMAP server 
> compliant to this RFC4551 ?

Yes, that IMAP server "complies" with the extension specification. I would 
argue that it is either misconfigured, buggy or just broken. As an example, 
an IMAP server which would e.g. increment UIDVALIDITY upon each SELECT 
still "conforms" to all applicable standards, and it's perfectly legal to 
behave in this way. Such a server would also be almost completely useless, 
but they will still be able to tick that mandatory "supports IMAP" checkbox 
on their product datasheet.

With kind regards,
Jan

-- 
Trojitá, a fast Qt IMAP e-mail client -- http://trojita.flaska.net/