[NNTP] LIST EXTENSIONS and an NNTPv2 capability

[Clive D.W. Feather]

I wrote:
> I should have realized that what I was proposing was too big a chunk for
> people to swallow in one go. Let me try again, explaining what I am
> thinking.

[...]

> I have to stop writing as I need to be elsewhere. Can people please think
> on what I've written so far and comment, and I'll try to continue later
> today.

Okay, to continue ...

(5) If we provide version number information, whether for the main protocol
or for extensions, what form should it take?

There are no doubt many views on this. My personal one is:
* The "major.minor" approach, where changes of "major" are incompatible
  while changes of "minor" are upwards compatible, is well-known and
  probably suffices for our needs.
* A way of providing extra information could be useful, for example when
  a new version is under development and clients want to know if the
  draft is supported.
* We can't restrict non-standardised extensions, but they could also find
  extensioning useful.
But this is a detail once (and if) we've agreed that versioning is worth
doing in the first place.

(6) Is there benefit in providing the information "this extension is
supported by the server but isn't available right now"?

On the one hand servers might want to keep some extensions secret until the
client has authenticated. On the other hand, is there any point in going
through various probing and authenticating steps if the extension is going
to turn out not to be there?

There's also the anomaly that AUTHINFO wants to show what capabilities are
available even when it's going to reject any authentication attempt.

(7) Once we answer all these questions, how do we apply the answers?

Given the answers I've proposed, I think a new command that presents all
this information is the right way to go. But I'm still happy to discuss
everything.

-- 
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            |                            |