Newsgroups: news.software.b
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Supersedes problems with rapid-fire articles
Message-ID: <1989Sep6.221624.28405@utzoo.uucp>
Organization: U of Toronto Zoology
References: <5200@looking.on.ca> <536@logicon.arpa> <3246@deimos.cis.ksu.edu>
Date: Wed, 6 Sep 89 22:16:24 GMT

In article <3246@deimos.cis.ksu.edu> tar@ksuvax1.cis.ksu.edu (Tim Ramsey) writes:
> [quoting the RFC]
>    If a message with the given Message-ID is present on the local
>    system, the message is cancelled...
>
>    If the system is unable to cancel the message as requested, it
>    should not forward the cancellation request to its neighbor systems.

If we're in a mood to really study the apocrypha, this passage does not
completely and unambiguously rule out what C News does and B2.10 did
(forwarding cancellations for messages that have not yet arrived).

Clearly, if a cancellation arrives when the message is present, the
cancellation must occur, by the first verse.  Clearly, if the system
is unable to perform a requested cancellation, the cancellation must
not be forwarded.  But what exactly should be done if a cancellation
arrives when the message is not present?  Is this "unable to cancel"?
That's a strange way of putting it.  As I've mentioned in another
posting, the real Usenet is full of non-ideal behavior that makes this
a not-too-surprising event.  The Holy Verses don't even mention leaving
a note saying "cancel this sucker when it gets here".  Leaving such a
note can reasonably be considered at least a tentatively-successful
cancellation, in which case forwarding would seem legal.

As mentioned in my other posting, there are powerful arguments, based
on robustness, for taking this point of view.
-- 
V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu