Subject: ENABLE⇒ PROVIDE | Re: SETTINGS_PRIORITY_SCHEME | Re: Setting to disable HTTP/2 Priorities
From: Kari Hurtta <[email-masked]>
To: Matthew Kerwin <[email-masked]>, HTTP Working Group <[email-masked]>
Cc: Lucas Pardue <[email-masked]>, Kari Hurtta <[email-masked]>, HTTP Working Group <[email-masked]>, Dmitri Tikhonov <[email-masked]>, Brad Lassey <[email-masked]>, Kari Hurtta <[email-masked]>
Date: Wed, 31 Jul 2019 21:00:56 +0300 (EEST)
List-Id: <ietf-http-wg.w3.org>

> On Wed., 31 Jul. 2019, 02:56 Lucas Pardue, <[email-masked]>
> wrote:
> 
> > Hi Kari,
> >
> > On Tue, Jul 30, 2019 at 4:52 PM Kari Hurtta <[email-masked]>
> > wrote:
> >
> >> Why boolean ("ENABLE") ?
> >
> >

> 
> At the risk of bike-shedding, I think calling it "enable" is a bit of an
> issue. The setting, as an advertisement of the sender's capability, should
> say something like "will ignore" (for disabling 7540 priorities) or "can
> understand" (for enabling some other scheme).
> 
> Unless we also feel the need to advertise "will not send"?
> 
> Cheers
> -- 
> Matthew Kerwin

Yes,

SETTINGS_ENABLE_* typically changes how HTTP/2 connection is
prosessed or allows some usages which otherwise produce
protocol error (example: SETTINGS_ENABLE_CONNECT_PROTOCOL).

Therefore these these typically allows only 0 ⇒ 1 transitions.
Feature which is enabled, is not allowed to be turned off because
it may effect handling of frames which are already sent by
other peer.

Therefore I think that

    SETTINGS_PROVIDE_HTTP2_PRIORITIES

is better name than

    SETTINGS_ENABLE_HTTP2_PRIORITIES

In other words this does not chahneg parsing of HTTP/2
frames. Even when this is set to 0, sending priorities
does not cause protocol error.

In SETTINGS_PROVIDE_HTTP2_PRIORITIES server asks
client to provide (or not provide) http/2 tree 
priorities.

( Another possible name is

  SETTINGS_PROVIDE_TREE_PRIORITIES

)

/ Kari Hurtta