On 07/03/2017 17:03, Martin Bjorklund wrote:
Robert Wilton <[email protected]> wrote:
in RFC 7950, The last paragraph, section 5.1.1 "Import and Include by
Revision" states:
"If a module is not imported with a specific revision, it is undefined
which revision is used."
But I was wondering if the above text is misleading, since section
5.6.5: "Implementing a Module" has the following two paragraphs:
If a server implements a module A that imports a module C without
specifying the revision date of module C and the server does not
implement C (e.g., if C only defines some typedefs), the server MUST
list module C in the "/modules-state/module" list from
"ietf-yang-library" [RFC7895 <https://tools.ietf.org/html/rfc7895>],
and it MUST set the leaf
"conformance-type" to "import" for this module.
If a server lists a module C in the "/modules-state/module" list from
"ietf-yang-library" and there are other modules Ms listed that import
C without specifying the revision date of module C, the server MUST
use the definitions from the most recent revision of C listed for
modules Ms.
The reason for these rules is that clients need to be able to know
the specific data model structure and types of all leafs and
leaf-lists implemented in a server.
This seems to imply that import without specifying the revision would
mean that the latest revision listed in ietf-yang-library must be the
one that is imported. Is that correct, or am I misinterpreting the
text?
This is correct.
Hence, should the last paragraph of section 5.1.1 be deleted?
No I don't think it should. From the perspective of a given module
that imports another module w/o revision, it is undefined which
revision is used - however in any given server the revision used is
deterministic.
I'm not sure what it really means for a YANG module to import another
module outside the context of a client/server, it seems somewhat abstract.
I still think that the text is misleading (similarly for 7.1.5). I
think that the draft would be clearer if these sentences were removed.
I don't think that it helps to say that something is undefined when that
is the implicit default of having no text there, and in all normal
scenarios, the version that would be imported is actually well defined.
So, I found the text to be misleading and unhelpful.
Rob
/martin
.
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