Re: [regext] Extension Prefixes, JSON Values, and URI Path Segments

[Tom Harrison <[e-mail]>]

Hi James,

On Tue, May 31, 2022 at 07:49:18PM +0000, Gould, James wrote:
> I'm not exactly sure where the term 'strict' model is coming from,
> which I assume is associated with Approach A "Tight Coupling".

That's right.  See my earlier mail at
https://mailarchive.ietf.org/arch/msg/regext/6Xg0ViGGlV19Ka-JGhEdFSFjsKM/:

    I think this topic is sufficiently unclear that a new clarifying
    document should be written (and preferably finalised) before any
    document progresses that is not in accordance with a 'strict'
    reading of the current text.  (Such a reading (IMHO) has the RDAP
    conformance value as the extension identifier in the IANA
    registry, with that identifier used as-is as a prefix for new path
    segments and fields defined by the extension.)

> I believe the RFCs are sufficiently unclear to support all three
> approaches discussed thus far (A, B, and C).

While I think the RFCs are unclear, I don't think approach B or C is
supported by the current text or practice.  As best I can tell, both
of those approaches require the documents to be read as though the
registry is for both prefixes and extension identifiers, as discrete
things, even though:

 - in the seven years since these documents were finalised, no
   extension has been registered on that basis;
 - 7480 has "[t]he extension identifier is used as a prefix in JSON
   names and as a prefix of path segments in RDAP URLs"; and
 - when an extension that used a prefix as its identifier in the
   registry ('fred') was flagged on the list, the idea of prefix
   registration was disavowed
   (https://mailarchive.ietf.org/arch/msg/regext/gX7r-RXx5Zy-IUlNjPPu4EPPWzo/),
   and 7483 was updated (by way of 9083) to give effect to that
   intent.

An additional consideration is that the registered extensions that
don't fall into the same category as 'fred' (i.e. the 'category 1'
extensions from
https://mailarchive.ietf.org/arch/msg/regext/hDGnDuzPFXcO8zXTUKW-8IjIS6w/)
all follow approach A.

-Tom