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Re: Comments on draft-ietf-sieve-notify-mailto-07.txt

2008-04-03 06:07:28

Arnt Gulbrandsen wrote:

Alexey Melnikov writes:

Also, Arnt has raised a good question about whether implementations are allowed to strip/alter garbage in :message or subject URI header. I think this should be addressed as well.

This text from 2119 describes what we want perfectly, IMO: "there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course."

While using SHOULD here might be fine, not describing valid reasons for violating the SHOULD when they are known in advance is a very bad thing. I always prefer documents that explain background/motivation.

Also, image that we update the text to read:

  o  The "Subject:" field of the notification message SHOULD contain the
     value defined by the :message notify tag, as described in
     [Notify].  If there is no :message tag and there is a "subject"
     header on the URI, then that value SHOULD be used.  If that is
     also absent, the subject SHOULD be retained from the triggering
     message.  Note that Sieve [Variables] can be used to advantage
     here, as shown in the example in Section 3.

I read this as allowing an implementation to ignore :message and/or the Subject URI header unconditionally. Is this something we actually want to encourage? I certainly wouldn't want to.

A much better approach is to at least explain what are valid reasons for violating the SHOULD and optionally use MUSTs.