[NNTP] LISTGROUP

[Clive D.W. Feather]

Mark Crispin said:
>> These three-digit codes are *ARBITRARY*. While the structure might not be
>> what we would choose today, it's what we've got. There is *NO* benefit to
>> changing it, particularly using some baroque arrangement that returns
>> different codes to different clietns.
> The benefit is compliance with standard Internet protocol architecture.

Meaning what? Just where is this "standard Internet protocol architecture"
documented?

> I don't understand why the NNTP community is so determined to defy 
> Internet standards and produce something which is similar, but different. 
> I really hope that we are past the "news is news and mail is mail and 
> ne'er the twain shall meet" attitude.

"A foolish consistency is the hobgoblin of little minds." [Emerson]

Just what benefit does compliance with this "standard" produce? Client code
still needs to understand specific codes or simply say "it begins 4 or 5,
it failed, tough luck". This is *not* the same as mail where retrying later
can produce different results.

As I said, if we were starting from scratch I would agree with you, but it
is COMPLETELY AND UTTERLY POINTLESS trying to change things now. That would
be *foolish* consistency.

>> LISTGROUP currently says:
>>    (the arguments on the initial response line are the same as
>>    for the GROUP command)
>> and
>>    In all other aspects the LISTGROUP command behaves identically to the
>>    GROUP command.
>> That text will be staying.
> 
> That does not answer the objection.  The values (not "arguments" -- yet 
> another thing that needs fixes)

Wrong: they are "arguments"; it says so in 3.2.

> on the response line are documented 
> independently in LISTGROUP and with subtly different wording.

Where? As far as I can see, 6.1.2.1 uses the same wording as 6.1.1.1, and
6.1.2.2 just has the text you quote.

> That 
> indicates that their semantics are different;

I disagree. But I don't see the "subtly different wording" you do.

> The text
>     (the arguments on the initial response line are the same as
>     for the GROUP command)
> clearly states that the values have the same syntax and names, not that 
> their semantics are the same.

"the same" covers everything, not just some aspects.

>>> There is no reason why the three zeros response should be allowed in an
>>> NNTPv2 compliant server.
>> There is no reason why it should not be allowed.
> The three zeros response implies that article numbers have been reset, and 
> that the client should discard all knowledge of article numbers. 

No it does not. It indicates an empty group.

On the contrary, a three zeros response does NOT invalidate the requirement
that:

   whenever a subsequent GROUP command for the same newsgroup is issued,
   either by the same client or a different client, the reported low
   water mark in the response MUST be no less than that in any previous 
   response for that newsgroup in any session, and SHOULD be no less
   than that in any previous response for that newsgroup ever sent to
   any client.  Any failure to meet the latter condition SHOULD be
   transient only.

We deliberately decided not to provide a way for a server to reset article
numbers and start again at 1; it's too rare an event to clutter up the
protocol.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
Thus plc            |                            |