On 31/01/2019 10:58, Martin Bjorklund wrote:
Andy Bierman <[email protected]> wrote:
On Thu, Jan 31, 2019 at 12:44 AM Martin Bjorklund <[email protected]> wrote:
Andy Bierman <[email protected]> wrote:
Hi,
I do not agree these changes should be made at this late date.
It seems to me that in order to support a feature you have to implement
it,
and therefore if any features are set then the module is implemented, not
imported.
But this is not what RFC 7950 says about implement:
A server implements a module if it implements the module's data
nodes, RPCs, actions, notifications, and deviations.
All features should be set to false in an import-only module.
IMO this interpretation holds for typedef modules like iana-crypt-hash.
We list that as implemented (because it is) and the features that are
supported are set.
If a module consists only of typedefs, there is no problem.
Conformance "import" or "import-only" modules exist in YL b/c modules
may have a mix of typedefs and data nodes etc.
So in the case that Lada brought up, a server would have to list the
module as implemented with a certain set of features; and then also
deviate all nodes/rpc/notifc etc as 'not-implemented'.
So what. Using deviate(not-supported) to cherry-pick what you want to
implement
out of a module is how it is supposed to work.
A server has to implement a feature to advertise it.
As per 7950, this is not true, as I pointed out earlier.
Note that with current YL (RFC 7895), it *is* in fact possible to
handle this case; you can list the features supported for an
import-only module. The new YL removes this possibility (by
mistake).
This presumably also means that clients/servers also have to handle the
fact that different features can be advertised for each revision of an
import-only module that has been imported.
Thanks,
Rob
/martin
Therefore the module containing the feature cannot be import-only.
/martin
Andy
Andy
On Wed, Jan 30, 2019 at 11:03 AM Martin Bjorklund <[email protected]>
wrote:
Hi,
Ladislav Lhotka <[email protected]> wrote:
Hi,
unlike RFC 7895, 7895bis doesn't provide the "feature" leaf list for
import-only modules. But is it really so that features have no use in
such modules?
For example, an enum can depend on a feature, and if it is inside a
typedef, it can also be in an import-only module. What if that
feature
is defined in the same module?
I think you're right, and that this is an unfortunate omission.
The fix is simple though; we would have to add the leaf-list features
to import-only. Probably refactor the "feature" leaf-list into a
grouping so it works like the grouping location-leaf-list:
grouping feature-leaf-list {
leaf-list feature {
type yang:yang-identifier;
description
"List of all YANG feature names from this module that are
supported by the server, regardless whether they are defined
in the module or any included submodule.";
}
}
And then "uses feature-leaf-list":
OLD:
grouping module-implementation-parameters {
description
"Parameters for describing the implementation of a module.";
leaf-list feature {
type yang:yang-identifier;
description
"List of all YANG feature names from this module that are
supported by the server, regardless whether they are defined
in the module or any included submodule.";
}
NEW:
grouping module-implementation-parameters {
description
"Parameters for describing the implementation of a module.";
uses feature-leaf-list;
And in the list "import-only":
OLD:
uses location-leaf-list;
uses feature-leaf-list;
/martin
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