[NNTP] Extension snapshots 2

[Clive D.W. Feather]

Russ Allbery said:
> I think we should invert the sense of this, because that's what actually
> matches what people do in practice:
> 
>  o if the client wishes to use any reader commands, it SHOULD use the
>    MODE READER command immediately after the initial connection;
> 
>  o otherwise, it SHOULD NOT use the MODE READER command, but should be
>    prepared for some commands to be unavailable.
> 
> That avoids the issue that some reader servers do also provide IHAVE.

But it loses the warning that some of them don't!

How about this:

   o if the client wishes to use any "reader" commands, it SHOULD use
     the MODE READER command immediately after the initial connection;

   o otherwise it SHOULD NOT use the MODE READER command.

   In each case it should be prepared for some commands to be
   unavailable that would have been available if it had made the other
   choice.

Is that an acceptable compromise between the various messages we're trying
to get across?

>> Remember that "strange things" includes forgetting the currently
>> selected group. Put another way, does MODE READER reset the internal
>> state or not?
> It does not in INN.
>> We never did resolve that, and that's what I'm trying to avoid having to
>> do.
> That's probably a good thing, because I can't be sure how other servers
> might implement it.  However, I think I'd rather tell the client not to
> send it twice than talk about what the server might do if it does.  I am
> convinced by the above that it's probably worth telling the client not to
> send it twice.

Okay. So we're in general agreement on that. I'll follow up the details in
another message.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
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