[Last-Call] Opsdir last call review of draft-faltstrom-unicode12-03

[Tim Chown via Datatracker <[e-mail]>]

Reviewer: Tim Chown
Review result: Has Nits

Hi,

I have reviewed this document as part of the Operational directorate's ongoing
effort to review all IETF documents being processed by the IESG.  These
comments were written with the intent of improving the operational aspects of
the IETF drafts. Comments that are not addressed in last call may be included
in AD reviews during the IESG review.  Document editors and WG chairs should
treat these comments just like any other last call comments.

This document describes changes between Unicode 6.2.0 and 12.0.0 in the context
of IDNA2008.

The document is generally well-written, and is Ready for publication subject to
a small number of comments and nits, detailed below. being reviewed.

Note that I am not an expert in Unicode or IDNA2008.

General comments:

The draft discusses changes up to Unicode 12.0.0, but I see that Unicode 14.0.0
was recently published; should the changes made in those past 2 years be
included in this document?   Are they major, or minor, to readily allow this?

The draft talks about exceptions, but never explicitly says what an exception
is, to what, and what it would look like and where it would be documented.  It
would be useful for a non-expert reader to clarify this.

The draft includes several Appendix sections, but these are not mentioned in
the document.  I think the context of their inclusion should be given.

There are several sections which summarise the number of changes to characters
between specific versions.  It would be useful to include a reference to these
totals, where they are sourced from.   I found some summary numbers at
https://www.babelstone.co.uk/Unicode/HowMany.html, and I checked that the
“Assigned” totals there matched the totals for “PVALID + CONTEXTO/J and
DISALLOWED”, and these were correct against that source.  But I don’t know
where to check the CONTEXTO/J numbers; perhaps these 27 (2+25) items should be
listed in an appendix, or a specific reference given.

Comments:

In section 1, CONTEXT is explained, but the later use of CONTEXTJ and CONTEXTO
are not.  This would be useful to include.

Section 2, penultimate para, s the first use, unexplained, of CONTEXTO/J.

In Section 2, last para, maybe point forward to the security section regarding
the reason for conservatism?

In Section 3.1, changes from 6.2.0 to 7.0.0 are summarised, but in the Appendix
the difference listed is 6.3.0 to 7.0.0.  Is that intended?

Section 5, paragraph 2 it talks of future Unicode versions that might need
action, but given 14.0.0 is published now, can we say more than “might” here? 
Or do we publish this as a snapshot against 12.0.0 from two years ago?  I guess
this document’s origins were at the time of publication of 12.0.0.

Section 6 - cite the registry?

Nits:

Abstract:
“consisstent” -> “consistent”

Section 1:
Third to last para - “and IETF” -> “and the IETF”

Section 4, line 5, there’s an orphaned “(BackwardCompatible(G))”.

Section 5, “after review” -> “after the review” and “tuning. Like” -> “tuning,
like”

Section 7 - “do not” -> “does not”

Best wishes,
Tim