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Document: draft-ietf-extra-sieve-mailboxid-05
Reviewer: Pete Resnick
Review Date: 2020-11-30
IETF LC End Date: 2020-12-02
IESG Telechat date: Not scheduled for a telechat

Summary: Looking good. Just one minor issue and one nit.

Major issues:

None.

Minor issues:

Section 4 says:

   If there is no such mailbox, the "fileinto" action proceeds as it
   would without the ":mailboxid" argument.

But the in the example in section 6, it shows:

       if mailboxidexists "F6352ae03-b7f5-463c-896f-d8b48ee3" {
           fileinto :mailboxid "F6352ae03-b7f5-463c-896f-d8b48ee3"
                               "INBOX.harassment";
       } else {
           fileinto "INBOX.harassment";
       }

That appears correct, but as far as I can tell, it is semantically identical to:

           fileinto :mailboxid "F6352ae03-b7f5-463c-896f-d8b48ee3"
                               "INBOX.harassment";

That is, the rule in section 4 means that fileinto already does an implicit existence check and only uses the named mailbox if the one specified by the mailboxid doesn't exist. It's not that the example is particularly a problem, but it did confuse me for a few minutes while I tried to figure out what it was trying to do. Perhaps if the example was:

       if mailboxidexists "F6352ae03-b7f5-463c-896f-d8b48ee3" {
           fileinto :mailboxid "F6352ae03-b7f5-463c-896f-d8b48ee3"
                               "this.name.will.never.be.used";
       } else {
           fileinto "INBOX.harassment";
       }

or an example that did something other than "fileinto" it would have made a bit more sense. Certainly not absolutely necessary to fix, but a change might improve understanding.

Nits/editorial comments:

In sections 4.1 and 4.2, you have references that appear as "[!@RFC5490]" and "[!@RFC5879]". I assume that's some sort of markdown or other formatting tool mistake.