On Tue, 24 Sep 2002, Simon Josefsson wrote: > > That is also impossible in IMAP. Review sections 5.5 and 7.4.1. > The sections seem to only discuss multiple commands from one client. > I was thinking of server initiated emptying of mailboxes, or multiple > concurrent clients where one of them empties the mailbox.
Those sections also address that issue, but indirectly. See my answer to Larry Osterman's message for a more detailed answer. The situation that you are thinking of is forbidden. Once a server has advertised a message sequence number as being valid, that message sequence number remains valid until the server transmits enough untagged EXPUNGEs to decrement the exists count to a lover value. > Responding > with NO seems more appropriate than BAD in this case. You're confusing two mutally-exclusive situations. SITUATION 1: server initiated emptying of mailboxes, or multiple concurrent clients where one of them empties the mailbox, and the server has NOT yet transmitted any untagged EXPUNGEs. The messages still exist, and will continue to exist until the untagged EXPUNGEs are transmitted. RFC 2180 offers NO as an option; however I contend (and empirical evidence has shown) that OK is what works best. RFC 2180 offers three ways that OK can happen: 1) not allow the mailbox to be emptied 2) allow it but keep a "ghost" copy behind 3) allow it and return a dummy (mostly NIL) representation. BAD is *NOT* a correct response in this situation, and I contend that NO is also an ill-advised choice. SITUATION 2: server initiated emptying of mailboxes, or multiple concurrent clients where one of them empties the mailbox, and the server has ALREADY transmitted the untagged EXPUNGEs to reduce the exists count to zero. An attempt by the client to access any message sequence number results in a BAD until such time as the server transmits an EXISTS with a non-zero value. OK or NO are *NOT* correct responses in this situation. > If the server > knew that itself, or a different client, did not empty the mailbox, > only then BAD could be used. Huh? -- Mark -- http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate.
