Adding feature to top level container doesn't work

[shmuelnatan]

Let's say I have the following two yang files (one has a feature and the other doesn't).

module module-foo {

    yang-version "1";

    // namespace
    namespace "http://foo/namespace";

    feature foo-feature;
    grouping foo-top {
        container foo-container {
            if-feature foo-feature;
            leaf foo-leaf {
                type string;
           }
       }
    }
    uses foo-top;
}

module module-boo {

    yang-version "1";

    // namespace
    namespace "http://boo/namespace";

    grouping boo-top {
        container boo-container {
            leaf boo-leaf {
                type string;
           }
       }
    }
    uses boo-top;
}

I do not add to my config file <CLICON_FEATURE>module-foo:feature-foo</CLICON_FEATURE>.
My database looks like this

<config>
   <module-boo xmlns="http://boo/namespace">
      <boo-leaf>boo</boo-leaf>
   </module-boo>
   <module-foo xmlns="http://foo/namespace"/>
</config>

I then want to bind the database with xmldb_put using OP_CREATE but this function fails due to an unknown element from the foo module. There is no binding done prior to using this function.
I think it's connected to the fact that the only info in the module is not enabled due to the feature that is not set.

P.S. We do not want to enable CLICON_YANG_UNKNOWN_ANYDATA to avoid problems in the future.

[olofhagsand]

I think your db example is wrong. I think it is supposed to look like this?

<config>
   <boo-container xmlns="http://boo/namespace">
      <boo-leaf>boo</boo-leaf>
   </boo-container>
   <foo-container xmlns="http://foo/namespace"/>
</config>

Is that correct?

[olofhagsand]

If so, I get the following error when loading that content as s startup-db:

olof@alarik> sudo clixon_backend -Ff /usr/local/etc/example.xml -s startup
Apr  1 12:43:36: clixon_backend: 598 
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
    <rpc-error>
      <error-type>application</error-type>
      <error-tag>unknown-element</error-tag>
      <error-info>
        <bad-element>foo-container</bad-element>
      </error-info>
      <error-severity>error</error-severity>
    <error-message>Failed to find YANG spec of XML node: foo-container with parent: config in namespace: urn:example:clixon</error-message>
  </rpc-error>
</rpc-reply>
Apr  1 12:43:36: startup_failsafe: 320: Database error: Startup failed and no Failsafe database found, exiting

[olofhagsand]

This may be the same consequence that you pointed out with CREATE.
I am unsure what to do with this, it would be good to have some reference from RFC7950 on how to act here.
What would be your expected behavior?

[olofhagsand]

Some info here: https://www.rfc-editor.org/rfc/rfc7950.html#section-7.20.1
Notably:

Schema nodes tagged with an "if-feature" statement are ignored by the server unless the server supports the given feature expression.

Which could indicate that clixon throwing an error is wrong, the presence should just be "ignored"

[shmuelnatan]

I think your db example is wrong. I think it is supposed to look like this?

<config>
   <boo-container xmlns="http://boo/namespace">
      <boo-leaf>boo</boo-leaf>
   </boo-container>
   <foo-container xmlns="http://foo/namespace"/>
</config>

Is that correct?

This is correct. The expected behavior should be that foo-container should be ignored.

[olofhagsand]

Changing to enhancement: "Not supported features should be ignored, not throw errors"

[olofhagsand]

Fixed. Please verify.
Also described in https://clixon-docs.readthedocs.io/en/latest/yang.html#if-feature-and-anydata