version number

[Brad Fitzpatrick]

On Sat, 21 May 2005, Imran Ghory wrote:

> Can we add a protocol version number to the messages sent for
> future-proofing reasons ?

I tend to go with "No version means version 1" because that's easiest, and
I never know the best practices when it comes to whether you do
"<major>.<minor>" and also have a "required_major" request argument, or
what.

Lay out a plan and I'm game.  I just can't come up with anything good
myself, so I was going to deal with it later.

Though I'm probably inclined to do what HTTP does, because I know that
spec and rules, and others probably do:

- request advertises <major>.<minor>

- identity server replies with <major>.<minor>, and also using features
  it knows the requester can do

- an identity server that can't deal with a <major> difference has to
  abort and not try to reply.

But that only worked for HTTP because there's never been a 2.0 spec!

Look how shitty it worked out for SSH:  everybody advertises 1.9999
to mean that they can do both 1.0 and 2.0.   Lame.

Ideas?

- Brad