[Imap-protocol] FETCH/STORE on out-of-range sequence number

[Mark Crispin]

On Fri, 16 Nov 2007, Dan Karp wrote:

> If there are 50 messages in the mailbox and a client requests

>   A001 FETCH 52 (FLAGS)

> then what are the acceptable server responses?


A001 BAD Invalid sequence number.


> I'm currently

> treating it as an example of RFC 2180 section 4.1.2 and returning

>   A001 NO Some of the requested messages no longer exist


It's a BAD because there is no way that a compliant client can reference 
an invalid sequence number.  The rules for EXPUNGE preclude it.

RFC 2180 section 4.1.2 was a terrible mistake and no server should ever do 
that.  4.1.3 is also pretty bad, and indicates a buggy server (or at least 
buggy mail store), but it is better than 4.1.2.  A server should do either 
4.1.1 or 4.1.4 instead.

Note as well that RFC 2180 is Informational.  The fact that an 
Informational RFC says something does not make it normative.

-- Mark --

http://panda.com/mrc
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