[NNTP] LISTGROUP

[Russ Allbery]

Charles Lindsey <chl at clerew.man.ac.uk> writes:

> However, there is one niggle. Suppose the group has become empty since
> yesterday (a mass expiry/cancellation/whatever). It is now legitimate
> (though deprecated) to reset the low water mark to zero and start off
> from there (well, that is one interpretation of section 6.1.1.2, though
> the wording does seem a little contradictory).

Er, no, it most certainly is not legitimate to do that.  It is legitimate
to return all zeroes in response to the GROUP command, but when another
article comes in, it has to be numbered higher than any previous article.

6.1.1.2 only governs the syntax of the return from GROUP, not the internal
article number.  For the internal article number, please see section 6, in
particular:

   [...]
   Another key is composed of the newsgroup name and the article number
   within that newsgroup.  That key MUST be unique to a particular
   server (there will be only one article with that number within a
   particular newsgroup), but is not required to be globally unique.
   [...]

   The server MUST ensure that article numbers are issued in order of
   arrival timestamp; that is, articles arriving later MUST have higher
   numbers than those that arrive earlier.  The server SHOULD allocate
   the next sequential unused number to each new article.

There are no exceptions for transiently empty groups.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>