[NNTP] Article Numbers Becoming Invalid (RFC 3977)

[Julien ÉLIE]

Hi Russ,

> there's an edge case here so we have to be careful about reading.  LAST
> returns 420 iff the article number is invalid, not just if the group is
> empty.  If you enter a group with one article, and that article is then
> cancelled (making the group empty), LAST should still return 422.

Yes.

I have just re-read the whole Section 6 about articles and the wording
in LAST about that edge-case is inconsistent.

GROUP defines the "first article in the group at the moment of selection"
as the "reported low water mark".  I'm OK with that.

But LAST uses a different wording:

   If the current article number is already the first article of the
   newsgroup, a 422 response MUST be returned.  If the current article
   number is invalid, a 420 response MUST be returned.  If the currently
   selected newsgroup is invalid, a 412 response MUST be returned.  In
   all three cases, the currently selected newsgroup and current article
   number MUST NOT be altered.


It is NOT the *first* article here, for 422.  I suggest to reword the
sentence this way:

   If the current article number is already lower or equal to the lowest
   existing article number (if any) in the newsgroup, a 422 response MUST
   be returned.

It will fix the consistency of the terminology and also deal with the
edge-case you mention.  Same for NEXT.

-- 
Julien ÉLIE

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