Re: [yang-doctors] Fwd: Re: Issue with [e-mail] and yangdump-pro

[Martin Bjorklund <[e-mail]>]

Andy Bierman <[e-mail]> wrote:
> On Sat, Dec 23, 2017 at 2:21 AM, Martin Bjorklund <[e-mail]> wrote:
> 
> > Hi,
> >
> > See section 9.10.3 in RFC 7950:
> >
> >    The string value of a node of type "identityref" in a "must" or
> >    "when" XPath expression is the referred identity's qualified name
> >    with the prefix present.
> >
> > and re. the prefix:
> >
> >    If the referred identity is defined in an
> >    imported module, the prefix in the string value is the prefix defined
> >    in the corresponding "import" statement.  Otherwise, the prefix in
> >    the string value is the prefix for the current module.
> >
> >
> > I most cases you should consider using derived-from-or-self instead of
> > equality test for identiyrefs.
> >
> >
> 
> So what is "the current module"?
> What is the resolution of 'X'? Is it foo:X or bar:X?

foo:X


/martin


> 
> 
> 
> >
> > /martin
> >
> >
> Andy
> 
> 
> >
> >
> >
> > Andy Bierman <[e-mail]> wrote:
> > > On Fri, Dec 15, 2017 at 4:38 AM, Radek Krejčí <[e-mail]> wrote:
> > >
> > > > Hi,
> > > > I'm adding Michal Vasko to cc, he knows better how these things are
> > > > checked in libyang.
> > > >
> > > > It seems to me that Andy refers the text which does not apply here. The
> > > > identity name was used as part of XPath expresion (when-stmt), so the
> > > > definition of the context nodes for the when-stmt (RFC 7950, sec
> > 7.21.5)
> > > > and XPath context rules should apply here. Not the rules for the
> > > > identityref's base statement. In this case, the when-stmt is in
> > augment so
> > > > the context node (which we also understand as the current node in this
> > > > case) is the augment's target node. And according to XPath context
> > rules
> > > > (RFC 7950, sec 6.4.1):
> > > >
> > > >  o  Names without a namespace prefix belong to the same namespace as
> > the
> > > > identifier of the current node.
> > > >
> > >
> > >
> > > I cc:ed YANG doctors to get more opinions...
> > >
> > > The current node is the augment-stmt.
> > > Note that it does not say context node, which is the target of the
> > augment.
> > > I think prefixes (and default prefix) are resolved in the module
> > containing
> > > the statement.
> > >
> > >
> > > module foo {
> > >
> > >    import bar { prefix b; }
> > >    identity X;
> > >
> > >    augment b:/some-node {
> > >       leaf test {
> > >          type string;
> > >          when "/b:some-node/b:other-node = 'X'";
> > >       }
> > >    }
> > > }
> > >
> > > module bar {
> > >
> > >    identity W;
> > >    identity X { base W; }
> > >    container some-node {
> > >        leaf other-node {
> > >          type identityref { base W; }
> > >        }
> > >    }
> > > }
> > >
> > > Q) Does other-node = 'X' resolve to foo:X or bar:X?  IMO: foo:X
> > >
> > >
> > >
> > > Andy
> > >
> > >
> > >
> > > > In this particular case, the augment node with the when-stmt augments
> > the
> > > > same module which defines napt44, so they are in the correct namespace
> > and
> > > > the identity name can be used without the prefix. So it should be fine,
> > > > while I believe that using prefix in the cases of identities is always
> > > > better approach. From the first sight (it may be challenging for human
> > to
> > > > correctly resolve the context/current node in some cases), I would also
> > > > expect prefix.
> > > >
> > > > I propose to keep the change in the draft (added nat prefix), since it
> > > > improves readability of the expression. But I don't think that it is an
> > > > error to ommit the prefix.
> > > >
> > > > Regards,
> > > > Radek
> > > >
> > > >
> > > > Dne 19.11.2017 v 20:42 Benoit Claise napsal(a):
> > > > > Hi Radek,
> > > > >
> > > > > Here is a bug report for you.
> > > > >
> > > > > Regards, Benoit
> > > > >
> > > > >
> > > > > -------- Forwarded Message --------
> > > > > Subject:      Re: Issue with [e-mail] and
> > > > yangdump-pro
> > > > > Date:         Sat, 18 Nov 2017 13:22:58 -0800
> > > > > From:         Andy Bierman <[e-mail]>
> > > > > To:   Benoit Claise <[e-mail]>
> > > > > CC:   [e-mail] <
> > > > [e-mail]>, Mahesh Jethanandani <
> > > > [e-mail]>
> > > > >
> > > > >
> > > > >
> > > > > Hi,
> > > > >
> > > > > yangdump-pro is correct. Every other compiler missed it...
> > > > >
> > > > > 9.10.2.  The identityref's "base" Statement
> > > > >
> > > > >    The "base" statement, which is a substatement to the "type"
> > > > >    statement, MUST be present at least once if the type is
> > > > >    "identityref".  The argument is the name of an identity, as
> > defined
> > > > >    by an "identity" statement.  If a prefix is present on the
> > identity
> > > > >    name, it refers to an identity defined in the module that was
> > > > >    imported with that prefix.  *Otherwise, an identity with the
> > matching
> > > > name MUST be defined in the current module or an included submodule.*
> > > > >
> > > > > Using [e-mail] and [e-mail]
> > > > >
> > > > > When I change 'natp44' to 'nat:natp44' in both when-stmts:
> > > > >
> > > > > andy@andy-homedev:~/Desktop/FD1289/IETF$ yangdump-pro
> > > > [e-mail] modpath=.
> > > > >
> > > > > *** /home/andy/Desktop/FD1289/IETF/[e-mail]
> > > > > *** 0 Errors, 0 Warnings
> > > > >
> > > > > andy@andy-homedev:~/Desktop/FD1289/IETF$
> > > > >
> > > > >
> > > > > Andy
> > > > >
> > > > >
> > > > > On Sat, Nov 18, 2017 at 11:07 AM, Benoit Claise <[e-mail]
> > > > <mailto:[e-mail]>> wrote:
> > > > >
> > > > >     Hi Andy,
> > > > >
> > > > >     Can you please have a look at [e-mail] at
> > > > http://www.claise.be/IETFYANGPageCompilation.html <
> > http://www.claise.be/
> > > > IETFYANGPageCompilation.html> .
> > > > >     yangdump-pro reports a new error, while the other validators are
> > > > fine.
> > > > >
> > > > >     Copying Mahesh, as YANG doctor.
> > > > >
> > > > >     Regards, Benoit
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> >