[NNTP] Article Numbers Becoming Invalid (RFC 3977)

[Julien ÉLIE]

Hi Clive,

> In general, with commands like ARTICLE, the intent is that the form without
> an argument is identical to the form with an argument, with the current
> article number used as the argument.
>
> So I would say that, in your example, 423 is the correct response. The 420
> response is *only* for the case that you entered an empty group and
> therefore GROUP wasn't able to assign an initial number.

OK, thanks.
What worries me most is that RFC 3977 explicitly does not allow 423 to be
returned for the third form of ARTICLE/HEAD/BODY/STAT, HDR and OVER.

It for instance led to the fact that INN 2.5.0 and INN 2.5.1 used 420
instead of 423 for HDR and OVER.  And maybe other servers (possibly new
implementations) did the same.  Besides, clients may also not expect 423
here...
And for the future, if someone implements RFC 3977 without looking at its
errata, then he will probably get it also wrong.  Not only it will lead to
broken HDR and OVER implementations regarding 420/423 but the issue will
also be present for ARTICLE/HEAD/BODY/STAT.
It is not a big deal but, still.

(Note that INN 2.5.0 and INN 2.5.1 are right for ARTICLE/HEAD/BODY/STAT
as they still use the historic value.
And INN 2.5.2 will use the right 423 response code for HDR and OVER.)



>> It is the same thing that happens when you send a GROUP command
>> and the first valid article in the newsgroup is not the reported
>> low water mark.
>
> This can't happen.

And what for LIST ACTIVE?
It uses the same definition of water marks.
Therefore, according to RFC 3977, LIST ACTIVE is also required to
return the real values for the first and last valid articles in
every newsgroup.
Well, this does not always happen!  (Hopefully the as-if principle
mentioned by Russ exists to allow servers not to cope with that
requirement.)



> There's one problem with the wording of 3977. In 6.2.1.2 we wrote:
>
> |  Note that a previously valid article number MAY become invalid if the
> |  article has been removed.  A previously invalid article number MAY
> |  become valid if the article has been reinstated, but this article
> |  number MUST be no less than the reported low water mark for that
> |  group.
>
> This is misusing the term "invalid article number". The wording should have
> been something like:
>
> |  Note that a previously valid article number MAY cease to refer to any
> |  article if that article has been removed, in which case use of that
> |  article number (explicitly or implicitly) will cause a 423 response. A
> |  previously removed article may be reinstated (but its number MUST be no
> |  less than the reported low water mark for that group), in which case
> |  that number will once again refer to that article.

OK.  Could you please open an erratum for it?
(and use two spaces after the end of the first period, when submitting it)

-- 
Julien ÉLIE

« Omnia uincit Amor et nos cedamus Amori. » (Virgile)