Subject: ISSUE: 4.3 contradicts 5.2.3

From: Russ Allbery <[email-masked]>
Date: Sat, 06 Sep 2008 21:23:26 -0700

I was reading over the current draft as part of a recent discussion on
news.admin.hierarchies and noticed that 4.3 contains the statement:

  One application/news-checkgroups message may contain information for one
  or more hierarchies and is considered complete for any hierarchy for
  which it contains a <valid-group>. In other words, an
  application/news-checkgroups body part consisting of:

      example.moderated         A moderated newsgroup (Moderated)
      example.test              An unmoderated test group

  is a statement that the example.* hierarchy contains two newsgroups,
  example.moderated and example.test, and no others. This media type
  therefore MUST NOT be used for conveying partial information about a
  hierarchy; if a group from a given hierarchy is present, all groups that
  exist in that hierarchy MUST be listed.

However, this is not true in the presence of chkscope in 5.2.3:

  A checkgroups message is interpreted as an exhaustive list of the valid
  groups in all hierarchies or sub-hierarchies with a prefix listed in the
  <chkscope> argument, excluding any sub-hierarchy where the <chkscope>
  argument is prefixed by "!". If no <chkscope> argument is given, it
  applies to all hierarchies for which group statements appear in the body
  of the message. Since much existing software does not honor the
  <chkscope> argument, the body of the checkgroups control message MUST
  NOT contain group statements for newsgroups outside the intended scope
  and SHOULD contain a correct newsgroup list even for sub-hierarchies
  excluded with "!" <chkscope> terms. News servers, however, MUST honor
  <chkscope> as specified here.

I think the fix would be to change to something like this:

  ...and is considered complete for any hierarchy for which it contains
  a <valid-group> unless accompanied by external information limiting
  its scope (such as a <chkscope> parameter to a checkgroups control
  message as described in Section 5.2.3)

and at the end, add:

  ...MUST be listed unless its scope is limited by external information.

but I'm not horribly happy with that.  It feels awkward.  I suppose the
other way of going about it is to redefine hierarchy, but I think that
would be tricky to do.

(I've seen the other messages to the group over the past week and will
reply.  I'm still on vacation for a couple more days.  I just wanted to
send this out before I forgot about it.)

-- 
Russ Allbery ([email-masked])             <http://www.eyrie.org/~eagle/>

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From: "Charles Lindsey" <[email-masked]>
Date: Tue, 16 Sep 2008 14:28:18 GMT

>  ...MUST be listed unless its scope is limited by external information.

Yes, that should cover it, but you might add that, where there IS
"external information" (and maybe the chkscope shold be mentioned
explicitly), it SHOULD be listed.

>other way of going about it is to redefine hierarchy, but I think that

A bit awkward, but good enough for our purpose (unless anyone can come up
with something better).

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133   Web: http://www.cs.man.ac.uk/~chl
Email: [email-masked]      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
PGP: 2C15F1A9      Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5

---

From: Russ Allbery <[email-masked]>
Date: Sun, 21 Sep 2008 17:17:30 -0700

> explicitly), it SHOULD be listed.

Done.

> A bit awkward, but good enough for our purpose (unless anyone can come up

I've committed this fix (see the separate commit message).  I'm certainly
happy to modify the wording if anyone comes up with something better.