Re: [netmod] Changing an identity base

On 30/01/2023 11:17, Martin Björklund wrote:
> Hi,
>
>
> Jernej Tuljak <jernej.tuljak@mg-soft.si> wrote:
>> On 30/01/2023 10:19, Italo Busi wrote:
>>> Yes, the intention is not to change the semantic of bar but to
>>> introduce a more “restricted” identity from which bar could be derived
>>>
>>> Something like introducing an identity for italian-car in between car
>>> and Ferrari identities
>>>
>> I understand your intention. I do not understand the intention behind
>> text in RFC 7950, however.
>>
>> My clarification request was aimed at RFC 7950 authors and whether a
>> revision like this could be considered as not changing the semantics
>> of the original identity definition because:
>>
>>     Otherwise, if the semantics of any previous definition are changed
>>     (i.e., if a non-editorial change is made to any definition other
>> than
>>     those specifically allowed above), then this MUST be achieved by a
>>     new definition with a new identifier.
>>
>> So, RFC authors: Is "NEWB:bar" definition semantically equivalent to
>> "OLD:bar" definition?
> I think that this change isn't allowed according to RFC 7950, but it
> should have been.  If there ever is a new version of YANG, this should
> be fixed.
>
> The quoted text says:
>
>    if a non-editorial change is made to any definition other
>    than those specifically allowed above, then this MUST be achieved by a
>    new definition with a new identifier
>
> This is a non-editorial change that is not "specifically allowed
> above".

That has been my interpretation as well so far. Our tools were 
implemented accordingly. I believe that the Pyang plugin also reports an 
error for a change like this.

Jernej

>
> /martin
>
>
>
>> Jernej
>>
>>> Italo
>>>
>>> *From:* Jernej Tuljak <jernej.tuljak@mg-soft.si>
>>> *Sent:* lunedì 30 gennaio 2023 08:51
>>> *To:* Italo Busi <Italo.Busi@huawei.com>; netmod@ietf.org
>>> *Subject:* Re: [netmod] Changing an identity base
>>>
>>> On 27/01/2023 17:54, Italo Busi wrote:
>>>
>>>      According to section 11 of RFC7950, the following change is
>>>      considered BC:
>>>
>>>         o  A "base" statement may be added to an "identity" statement.
>>>
>>>      Since, as explained in section 7.18.2 of RFC7950, the derivation
>>>      of identities is transitive, my understanding is that replacing a
>>>      "base" statement with new  "base" statement which is derived from
>>>      the previous one is also a BC change.
>>>
>>>      Considering the example below, the NEW (A) change is BC according
>>>      to section 11 of RFC7950. However, NEW (B) is equivalent to NEW
>>>      (A), since the new baz is derived from foo, and therefore it is
>>>      also a BC change.
>>>
>>>      Is my understanding correct?
>>>
>>>
>>> I'd like a clarification regarding this as well.  Is "NEWB:bar"
>>> definition semantically equivalent to "OLD:bar" definition?
>>>
>>> Jernej
>>>
>>>
>>>      Thanks, Italo
>>>
>>>      OLD
>>>
>>>      identity foo {}
>>>
>>>      identity bar {
>>>
>>>        base foo;
>>>
>>>      }
>>>
>>>      NEW (A)
>>>
>>>      identity foo {}
>>>
>>>      identity baz {
>>>
>>>        base foo
>>>
>>>      }
>>>
>>>      identity bar {
>>>
>>>        base foo;
>>>
>>>        base baz;
>>>
>>>      }
>>>
>>>      NEW (B)
>>>
>>>      identity foo {}
>>>
>>>      identity baz {
>>>
>>>        base foo
>>>
>>>      }
>>>
>>>      identity bar {
>>>
>>>        base baz;
>>>
>>>      }
>>>
>>>
>>>
>>>      _______________________________________________
>>>
>>>      netmod mailing list
>>>
>>>      netmod@ietf.org
>>>
>>>      https://www.ietf.org/mailman/listinfo/netmod
>>>