Re: [core] progressing ietf-core-yang-cbor and ietf-core-sid

[Carsten Bormann <[e-mail]>]

On 2020-01-15, at 19:28, Michael Richardson <[e-mail]> wrote:
> 
> 
> Carsten Bormann <[e-mail]> wrote:
>> On 2020-01-13, at 19:11, Michael Richardson <[e-mail]>
>> wrote:
>>> 
>>> o SIDs never change.
> 
>> That may require a little bit of expansion.  SIDs do change while I’m
>> editing the document on my laptop and not telling anyone else what I’m
>> doing.  But at some time, they freeze.
> 
> Actually, if things go well on your laptop, they don't.
> You might add/delete leafs and so you might roll through the SIDs quickly,
> and then, because you haven't published anything, decided to reset, but
> that's your business :-)

Exactly.

My question really was if we can state unambiguously when it stops being my business.

>> What is the specific event that makes a SID allocation immutable, even
>> if the underlying identifier goes away (and maybe comes back later)?
> 
>> What is the way we keep this memory?
> 
> There is the .sid file which records the allocations.
> You use --generate-sid-file (giving your allocation) to initialize the
> process, which creates a .sid file.  You do this only once.
> 
> You use --update-sid-file normally to allocate SID values from a YANG file.
> It keeps track not to re-use elements after the leaf is deleted, and makes
> sure to re-use numbers when the leaf has not changed.  Deleting and then
> adding a leaf with the *same name* should wind up with the SID being reused.

So when the development of a standard is completed, we hand IANA a SID file with dead SIDs in it?  Or how do we maintain the memory of those dead SIDs?  Are there boundaries through which a SID file can go that does remove dead SIDs?

> The SID file is some JSON.
> Here is an example:
>  https://github.com/anima-wg/constrained-voucher/blob/master/ietf-constrained-voucher-request%402019-09-01.sid

Yes.  The file format is fine, the question is whether we give enough guidance on how to handle the evolution of “the” SID file for a YANG module.

I think Andy Bierman has reminded us often enough that this is hard to get right.
Sorry for playing a bad copy of Andy today.

Grüße, Carsten