Re: [core] [Last-Call] [art] Artart last call review of draft-ietf-core-problem-details-05

[tom petch <[e-mail]>]

Just on the YANG point

On 24/06/2022 11:20, Ira McDonald wrote:
> Hi,
>
> Hmm...I knew I should have been silent in this thread...
>
> John - you're right that any future update to RFC 5646 will be carefully
> backwards compatible.
> And Martin could answer (off list) your question about possible future
> changes.
>
> Tom - many copies in YANG or anywhere else is a disturbing idea.  Any
> computer language
> that doesn't have a good mechanism for namespaces, import, and export isn't
> fully baked.
> And I know so little about YANG that I don't even know what it can do here.

Ira,

YANG does have import but it is a bit clunky.  The I2NSF have a cluster 
of six closely related modules which cries out for a common module but 
the WG chose not to use that approach so there is much replication, much 
ovelap in their modules e.g. with language tags.

The NETMOD WG produced RFC6991 which provided common types and is used 
by almost all YANG modules and 6991bis has just completed WGLC so that 
is the natural place to put a language type.  6991 works because it was 
based on decades of experience with SMI but other WG are not so skilled 
at judging when to create a common module and what to put in it.  The 
opsawg WG is an interesting case study therein.

So with Francesca raising this issue several times I have asked NETMOD 
to include a language tag construction in 6991bis but since the I-D has 
a long history and is much overdue, then I expect that they will be 
reluctant to act, but I have asked.

Tom Petch


> CORE - please delete *all* of your CDDL details for language tags and just
> use one of the
> several excellent libraries that correctly parse language tags, when needed.
>
> All - one of the  key ethical reasons for the Internet is fair access to
> information for all.  The
> correct use of language tags is really important.  The idea of inferring
> human language from
> the context is nonsense, because the upper layer context is often the first
> thing discarded.
>
> I will now leave it to Francesca to keep bothering the IESG about language
> tags and return
> to my cave and worry about automotive security.
>
> Cheers,
> - Ira
>
>
> *Ira McDonald (Musician / Software Architect)*
>
> *Chair - SAE Trust Anchors and Authentication TF*
> *Co-Chair - TCG Trusted Mobility Solutions WG*
>
> *Co-Chair - TCG Metadata Access Protocol SG*
>
>
> On Fri, Jun 24, 2022 at 4:54 AM tom petch <[e-mail]> wrote:
>
>> On 23/06/2022 22:08, Ira McDonald wrote:
>>> Hi Carsten,
>>>
>>> I take your point about copying from a given RFC.
>>>
>>> But the history of IETF Language Tags is RFC 1766 (1995), RFC 3066
>> (2001),
>>> RFC 4646 (2006), and RFC 5646 (2009).  It's a long time since 2009 and,
>> as
>>> Martin noted, there have been a variety of proposals for updating
>> language
>>> tags in the past 13 years, so it's reasonably likely that there will be a
>>> newer
>>> version at some point.  And since language tags are now quite structured,
>>> the chance of not needing syntax changes is fairly low.  This draft RFC
>> from
>>> CORE wouldn't catch up quickly, presumably.
>>
>> Probably a left field comment.
>>
>> I had not heard of, or forgotten about, language tags until the IESG
>> review of draft-ietf-i2nsf-nsf-facing-interface-dm drew a DISCUSS from
>> Francesca because the 26 YANG string that were meant to be human
>> readible had no language tags.  She pointed to RFC2277 while saying that
>> RFC5646 should be a Normative Reference.
>>
>> The I-D was revised to include a YANG leaf 'language' with a horrendous
>> YANG pattern spanning 25 lines.
>>
>> Two consequences.  The pattern, doubtless a gross simplification of what
>> it might have been, was wrong and was revised - I have not looked to see
>> if it makes sense now but then I did not spot the error in the first
>> place - so I have the sense that, like trying to specify a pattern for
>> IPv6 address, language tags are easy to get wrong.  Second there is now
>> a pattern of Francesca throwing DISCUSS at other similar I-D so language
>> tags, and their modelling in YANG, could get more attention (at least
>> while Francesca is on the IESG:-) her comments could have been made
>> about any number of earlier YANG RFC).  The pattern in the I2NSF I-D
>> cannot be imported into another YANG module, rather each YANG module
>> that draws a DISCUSS will contain a fresh copy.  If ideas evolve, then
>> there are likely to be many disparate copies.
>>
>> Tom Petch
>>
>>>
>>> Cheers,
>>> - Ira
>>>
>>>
>>>
>>> *Ira McDonald (Musician / Software Architect)*
>>>
>>>
>>> On Thu, Jun 23, 2022 at 2:34 PM Carsten Bormann <[e-mail]> wrote:
>>>
>>>> On 2022-06-23, at 13:13, Ira McDonald <[e-mail]> wrote:
>>>>>
>>>>> Hi Carsten,
>>>>>
>>>>> OK - you need to get this CORE document published quickly.
>>>>
>>>> Thank you.
>>>>
>>>>> But I still think that detailed CDDL would be a long-term mistake, for
>>>> the reason
>>>>> that Martin cited - i.e., copying/transforming grammars among RFCs is
>>>> fragile.
>>>>
>>>> Well, the RFC is immutable, so the act of making a copy cannot by itself
>>>> be fragile.
>>>>
>>>> What got us to now propose blunting that grammar is the strong
>> impression
>>>> that there may be less consensus about the grammar defined by RFC 5646
>> than
>>>> we thought.  So it seems the grammar in RFC 5646 is fragile, not the
>> act of
>>>> copying it out...
>>>>
>>>> https://github.com/core-wg/core-problem-details/pull/40/commits/bbe72e2
>>>>
>>>> (I’m making a point about copying here as I believe copying out snippets
>>>> of CDDL from RFCs and other specifications will be a significant part of
>>>> CDDL 2.0.)
>>>>
>>>> Grüße, Carsten
>>>
>>
>