> On 19 Apr 2016, at 17:35, Andy Bierman <[email protected]> wrote:
>
>
>
> On Tue, Apr 19, 2016 at 2:21 AM, Ladislav Lhotka <[email protected]> wrote:
>
> > On 19 Apr 2016, at 10:50, Martin Bjorklund <[email protected]> wrote:
> >
> > Andy Bierman <[email protected]> wrote:
> >> Hi,
> >>
> >> The ABNF for "default" is wrong in the deviate-*-stmt (add, replace,
> >> delete)
> >> Is says [default-stmt] but it should be *default-stmt
> >
> > Thanks, fixed.
> >
> > But for deviate-replace, it is not clear what the correct answer is.
> >
> > This is pretty clear:
> >
> > leaf foo {
> > type int32;
> > default 42;
> > }
> >
> > deviation /foo {
> > deviate replace {
> > default 10;
> > }
> > }
> >
> > But what about this:
> >
> > leaf-list bar {
> > type int32;
> > default 42;
> > default 43;
> > }
> >
> > deviation /bar {
> > deviate replace {
> > default 10;
> > default 11;
> > }
> > }
> >
> > Are all defaults changed?
> >
> > Compare with must and unique - they can not be replaced currently.
> >
> > In order to resolve this we probably need more text as well :(
> >
> >
> > OLD:
> >
> > The argument "replace" replaces properties of the target node. The
> > properties to replace are identified by substatements to the
> > "deviate" statement. The properties to replace MUST exist in the
> > target node.
> >
> >
> > NEW:
> >
> > The argument "replace" replaces properties of the target node. The
> > properties to replace are identified by substatements to the
> > "deviate" statement. The properties to replace MUST exist in the
> > target node. If multiple properties exist in the target node, all
> > of them are replaced with the new properties defined in the
> > substatements to the deviate statement.
> >
> > + add an example to the section "Usage examples":
> >
> > NEW:
> >
> > In this example, the original definition of a leaf list has two
> > default values "42" and "43:
> >
> > leaf-list bar {
> > type int32;
> > default 42;
> > default 43;
> > }
> >
> > A server can change this to the values "10" and "11" instead:
> >
> > deviation /base:bar {
> > deviate replace {
> > default 10;
> > default 11;
> > }
> > }
>
> Makes sense. However, Balazs asked previously about multiple deviations with
> the same target node:
> '
>
>
>
> The replace and delete variants all need to work the same.
> They apply to all the default-stmts.
>
> leaf-list foo {
> type int32;
> default 10;
> default 20;
> }
>
>
>
> https://www.ietf.org/mail-archive/web/netmod/current/msg14532.html
>
> It seems there has been no resolution. In this case, if default values are
> replaced multiple times, which version will take effect?
>
>
>
> This will be implementation-specific.
>
>
>
> module dev1:
>
> deviation /foo {
> deviate replace {
> default 30;
> }
> }
>
>
>
> module dev2:
>
> deviation /foo {
> deviate replace {
> default 40;
> }
> }
>
> If first one wins or last one wins, then it depends on the order that
> the deviations are loaded and processed by the parser.
>
> Which version of /foo is really in use?
>
> leaf-list foo {
> type int32;
> default 30;
> }
>
> leaf-list foo {
> type int32;
> default 40;
> }
>
>
> This follows the requirement that the statement be valid at the end,
> but it is really broken wrt/ which deviation wins. This applies to
> many deviations, not just default.
>
> There needs to be a rule that a deviation duplicates are not allowed.
I agree, although it is a bit awkward because it would be an inter-module rule.
Lada
>
>
> Lada
>
>
> Andy
>
> >
> >
> > Also, change the grammar:
> >
> > OLD:
> >
> > deviate-replace-stmt = deviate-keyword sep replace-keyword-str optsep
> > (";" /
> > "{" stmtsep
> > ;; these stmts can appear in any order
> > [type-stmt]
> > [units-stmt]
> > [default-stmt]
> > [config-stmt]
> > [mandatory-stmt]
> > [min-elements-stmt]
> > [max-elements-stmt]
> > "}") stmtsep
> >
> > NEW:
> >
> > deviate-replace-stmt = deviate-keyword sep replace-keyword-str optsep
> > (";" /
> > "{" stmtsep
> > ;; these stmts can appear in any order
> > [type-stmt]
> > [units-stmt]
> > *must-stmt
> > *unique-stmt
> > *default-stmt
> > [config-stmt]
> > [mandatory-stmt]
> > [min-elements-stmt]
> > [max-elements-stmt]
> > "}") stmtsep
> >
> >
> >
> >
> >
> >> Is it intentional that the ABNF for deviate-delete-stmt leaves out
> >> config, mandatory, max-elements, and min-elements?
> >> I understand why "type" cannot be removed.
> >
> > I don't really remember, but I can see that if you want to "delete"
> > min-elements you can replace it and set it to 0.
> >
> >> IMO the rest of the statements should be removable.
> >
> >> Sec. 7.20.3.2 does not mention the restrictions indicated in the ABNF.
> >> This section should make it clear a leaf has only 1 default
> >> and the 0..n refers to leaf-list only.
> >
> > In general, the result after applying deviations must be valid - e.g.,
> > you cannot deviate "foo" as the default for an int32 leaf.
> >
> >> It should also be clear that the "deviate add default" for a leaf-list
> >> is YANG statement order-dependent.
> >>
> >> Not as obvious -- a config=false leaf-list can have duplicate default
> >> values.
> >> The deviate-stmt has no way to specify which 1 to delete or replace
> >> if there are duplicates.
> >
> > Unless replace will replace *all*, as suggested above.
> >
> >
> > /martin
> >
> > _______________________________________________
> > netmod mailing list
> > [email protected]
> > https://www.ietf.org/mailman/listinfo/netmod
>
> --
> Ladislav Lhotka, CZ.NIC Labs
> PGP Key ID: E74E8C0C
>
>
>
>
>
--
Ladislav Lhotka, CZ.NIC Labs
PGP Key ID: E74E8C0C
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