Ladislav Lhotka <lho...@nic.cz> wrote:
>
> > On 05 Apr 2016, at 11:09, Martin Bjorklund <m...@tail-f.com> wrote:
> >
> > Andy Bierman <a...@yumaworks.com> wrote:
> >> On Mon, Apr 4, 2016 at 1:08 PM, Ladislav Lhotka <lho...@nic.cz> wrote:
> >>
> >>>
> >>>> On 04 Apr 2016, at 16:15, Andy Bierman <a...@yumaworks.com> wrote:
> >>>>
> >>>>
> >>>> On Mon, Apr 4, 2016 at 12:01 PM, Ladislav Lhotka <lho...@nic.cz> wrote:
> >>>>
> >>>>> On 04 Apr 2016, at 15:57, Andy Bierman <a...@yumaworks.com> wrote:
> >>>>>
> >>>>> Hi,
> >>>>>
> >>>>> I do not see any reason to prohibit this use of action-stmt
> >>>>> or notification-stmt. If the list has no keys then there is
> >>>>> no need to distinguish instances because the data model defines
> >>>>> no such semantics.
> >>>>
> >>>> If such a keyless list has multiple entries, how can an action request
> >>> specify which of the list entries it is tied to?
> >>>>
> >>>> it must be be relevant to distinguish instances or else the designer
> >>>> would have defined a key.
> >>>>
> >>>>
> >>>>>
> >>>>> What breaks if this is allowed?
> >>>>
> >>>> The behaviour is undefined.
> >>>>
> >>>>
> >>>>
> >>>> IMO lists without keys are a really bad idea.
> >>>> But the semantics are fully defined according to YANG.
> >>>> If the list has no keys then there is no instance information
> >>>> relevant to the data model. The action or notification is passed
> >>>> all the keys (happens to be zero in this case).
> >>>
> >>> To my understanding, each action request has to specify the unique
> >>> instance that's the "receiver" of the action. If this cannot be done, it
> >>> is
> >>> IMO a problem in the spec.
> >>>
> >>> An alternative implementation of actions would be to use instance
> >>> identifiers instead of an explicit data hierarchy, and in this case it
> >>> would be possible to use indices for identifying entries. But the
> >>> hierarchy
> >>> provides no such option.
> >>>
> >>> It's not a big issue, but there is already a couple of rules regarding
> >>> where actions can and cannot be defined, so this would be another one
> >>> intended to avoid potential ambiguity.
> >>>
> >>>
> >> I agree actions were not considered when keyless lists were allowed in
> >> YANG.
> >> There was an assumption that this data is always read-only that is no
> >> longer true in YANG 1.1.
> >>
> >> I certainly prefer adding a restriction than redoing the way actions work.
> >> Using /foo[5] does not work because entry "5" might move or get deleted,
> >> so the numbering is not stable.
> >
> > How about:
> >
> > An action MUST NOT have any ancestor node that is a list node without
> > a "key" statement.
>
>
> Or rather:
>
> An action MUST NOT be defined for a node that is a list without a
> "key" statement, or has a list node without a "key" statement as its
> ancestor.
I don't see the difference. Even in:
list foo {
action bar { ... }
}
"foo" is an ancestor to "bar".
/martin
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