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Re: Meaning of the term "optional" in the TPE spec

From: Roy T. Fielding <fielding@gbiv.com>
Date: Mon, 10 Sep 2012 16:19:37 -0700
Cc: "public-tracking@w3.org" <public-tracking@w3.org>
Message-Id: <9F749F23-C00C-4648-8A41-37FF9F91A806@gbiv.com>
To: Matthias Schunter <mts-std@schunter.org>
On Sep 10, 2012, at 1:19 PM, Matthias Schunter wrote:

> another potential clarification that we discovered is that we as a group
> need to validate that we agree when the TPE spec uses the term OPTIONAL
> (defined by RFC2119 as fields/features that are completely optional,
> i.e., servers and user agents can freely choose to implement them or not).

The spec should already do that.  If a field is optional except under certain
circumstances, then it should say that.  The fields that are purely optional
do not have any dependent requirements yet.  If there is a mistake in the
drafting, please note it as a bug.

> I believe that this is the right meaning for some of the fields in the
> TPE spec. An example is the extensions to the DNT header or the
> third-party field of the tracking status resource.
> 
> However, we need to double-check that all fields that are declared
> OPTIONAL are never needed for any critical use case.
> If we are honest to ourselves, we should usually only claim that our
> spec implements a use case iff this use case does not depend on such
> optional fields.

Yes, nobody has claimed otherwise.

> fyi:  for the fields of the tracking status resource, I believe the
> following to be true:
> - we agreed that the third-party fields is truly optional (sites can
> freely choose whether they may or may not declare third-parties)
> - for the "same-party" field, this is less clear. Without this field,
> user agents may be confused if multiple sites say "intended for 1st
> party use" without declaring each other to be part of the same party.

What do you mean by "it isn't clear"?  Right now, same-party is not
required under any circumstances.  I think that's pretty clear.  The
only reason it was proposed as optional is because it is an implementation
burden on first party sites.

In order to make it required, somebody in the WG (which includes the
draft authors) needs to propose that it be required. Since nobody has
done that yet, AFAIK, it isn't required.

Are you making that proposal?  If so, please just do so and let the
WG discuss.  If there are no objections, it goes in.  If there are
objections, we make a call for consensus and the the chairs decide.

> Did we overlook spec language that contains these requirements? If not,
> how would you clarify this issue?

I did not overlook it.  We simply haven't made it a requirement yet.

> Should we go through the fields one-by-one and discuss which fields
> should not be completely optional?

I would hope that people are doing that while reviewing the document.

....Roy
Received on Monday, 10 September 2012 23:20:00 UTC

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