Re: [hybi] Adding clarification regarding future revisions (Was: Proposed way forward for WebSockets)

[Dave Cridland <[e-mail]>]

On Wed Jul 28 12:54:23 2010, Joe Hildebrand wrote:
> On 7/27/10 6:29 PM, "Jamie Lokier" <[e-mail]> wrote:
> 
> > Concluding:
> >
> >   - *Using* version numbers and user-agent strings instead of
> >     explicit feature checks is an anti-pattern because it blocks
> >     updates to those numbers and strings and forces them to lie.
> >
> >   - But *not providing them* is an anti-pattern because it
> >     prevents workarounds and thus blocks deployment of new  
> features.
> 
> There is precedent for this.  In XMPP, we have a version number,  
> which we
> originally set to 1.0 in order to signal support for the standard  
> version,
> rather than the pre-standard version.  We defined a version policy,  
> but have
> successfully fought off all attempts to change the version number by
> providing other feature negotiation mechanisms.  It's still nice to  
> know
> it's there if we need it, however.

Right, the version in XMPP is used as a flag-day, and one of the  
capabilities its presence signals is the ability to negotiate  
features.

Prior versions - ie, no version at all - could not negotiate features.

Dave.
-- 
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