[NNTP] Article Numbers Becoming Invalid (RFC 3977)

[Sabahattin Gucukoglu]

On 1 Jan 2010, at 17:25, Julien ÉLIE wrote:
>> the only use for code 420 is after commands following entering
>> an empty group, since it's impossible to invalidate the article
>> pointer by any other means.
> 
> ARTICLE
> 220 100 <example at mid> article follows
> [...]
> 
> Suppose you wait for two minutes and the article is cancelled
> during that period, and you issue again the command:
> 
> ARTICLE
> 420 No current article selected
> 
> The article pointer has been made invalid (though it still points
> to 100).

Doh!  Yes, sorry, of course, that's right.  My brain is clearly not working today. :-)

> 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.  The article pointer points to the reported low
> water mark, and is therefore invalid.  You have a 420 error.
> NEXT will give you, if the group is not empty, the first valid
> article in the newsgroup.
> 
> It is how it currently works, at least with INN.  But it should
> be clarified in RFC 3977.
> 
> ** Note that maybe INN is wrong! **

I thought we'd "Established" that the article pointer is valid on group entry.  It is wrong for NEXT to operate when the article number is invalid.  The only way inn can hope to be in conformance is if the low watermark *just so happens* to be the first article, which of course is fine.  Reinstatement is then some sort of implementation detail which I can't think of just now. :-)

Cheers,
Sabahattin