Re: [netmod] yang-08: changing a default

[Ladislav Lhotka <lhotka at cesnet.cz>]

Martin Bjorklund píše v Po 09. 11. 2009 v 12:47 +0100:
> Ladislav Lhotka <lhotka at cesnet.cz> wrote:
> > I am just trying to understand what the acceptable (and likely) paths
> > are for module evolution, perhaps without the need for giving an exact
> > revision number.
> > 
> > The change of a leaf definition from mandatory=true to (mandatory=false
> > & new default definition) seems a natural way for establishing a data
> > model default based on operational experience, and it shouldn't cause
> > any serious interoperability problems.
> 
> This is also covered by the proposed update, repeated here again:
> 
> - A "default" statement may be added to a leaf that does not have a
>   default value (either directly or indirectly through its type).
> 
> We already have:
> 
> - A "mandatory" statement may be removed or changed from "true" to
>   "false".

My point was rather that these two should mostly be used together -
otherwise, an optional leaf without any default that gets a default in
the next version looks suspicious and probably indicates the server used
some value behind the scenes in the old version, which should be banned.
Or is there any use case for such a situation?

Lada

> 
> 
> 
> /martin
-- 
Ladislav Lhotka, CESNET
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