[NNTP] Article Reinstatement

[Clive D.W. Feather]

Sabahattin Gucukoglu said:
> I think we really need an effort to roll all these errata into 3977bis.

I'm not clear that there is an error here.

>>>> It is not an RFC-compliant behaviour. min could not have been set
>>>> to 2.
> Yes, (as Clive correctly points out) very sensible.  But how do we distinguish, inside the server, an article that *might* be reinstated and one that just expired?

That's up to the implementer.

>>> So what does a server do when the lowest-numbered article is pending
>>> reinstatement and the client requests it?
>> The news server just answers the article does not exist:

Exactly.

> Is there any language which specifically allows the use of these codes for reporting an invalid article number because of a (possible) reinstatement?

Until and unless the article is reinstated, it does not exist. Full stop.

Reinstatement is either:
(1) a rare event (e.g. because of an erroneous cancel)
(2) a side-effect of running a server farm that isn't perfectly in sync.

>> And also the fact that articles can expire and no longer be present in the news spool.  The low water mark does not necessarily point to a still retrievable article at the time an ARTICLE command is sent.
> That's fine; such an article really would be no longer existent.

Until and unless an article has been reinstated, it does not exist.

>>> By which we understand that an invalid article response will result
>>> from requesting a removed article, yes?
>> Not "invalid", but "inexistent".
> Yes, OK, this needs to be rolled into bis.

What needs to be rolled in? 6.2.1.2 makes it perfectly clear that article
numbers are invalid once the article is removed, and then become valid
again if it is reinstated.

> This doesn't always work, but it does work 99% of the time.  Especially since many servers just don't do the reinstatement thing at all.

"Those who do not learn from history are doomed to repeat it."

The reinstatement wording was carefully worked out after experience with
real users and real server farms that weren't in perfect sync. You might
examine demon.service from 1995 to 1999 for some examples of upset users
(no, I can't give exact cites from this long ago).

-- 
Clive D.W. Feather          | If you lie to the compiler,
Email: clive at davros.org     | it will get its revenge.
Web: http://www.davros.org  |   - Henry Spencer
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