lyd_parse_data_mem behavior

[rabhat31]

Hi, I'm running into a weird issue with parsing XMLs under certain conditions.

1. Create a context and load the models "Cisco-IOS-XE-native" and "Cisco-IOS-XE-mdt-cfg".
2. Parse an XML into the context using lyd_parse_data_mem with only the LYD_PARSE_STRICT flag.
3. When parsing an XML tree under the <native> tree , lyd_parse_data_mem returns a NULL lyd_node.
4. When parsing an XML tree under the <mdt-cfg-data> tree , lyd_parse_data_mem returns a properly populated lyd_node.
5. When I use the flags LYD_PARSE_STRICT and LYD_PARSE_ONLY, then both and XMLs get parsed. Also when I explicitly validate these nodes, nothing gets deleted.
6. When I parse an XML which is a combination of both mdt-cfg-data and native tags, only the mdt config gets parsed whereas native does not.

Example XMLs: MDT XML:

<mdt-config-data xmlns="http://cisco.com/ns/yang/Cisco-IOS-XE-mdt-cfg">
    <mdt-subscription>
      <subscription-id>12345</subscription-id>
      <base>
        <stream>ABC</stream>
        <encoding>XYZ</encoding>
      </base>
    </mdt-subscription>
    <mdt-named-protocol-rcvrs>
      <mdt-named-protocol-rcvr>
        <name>DEF</name>
        <protocol>native</protocol>
      </mdt-named-protocol-rcvr>
    </mdt-named-protocol-rcvrs>
    <proto-grpc-profile>
      <name>GHI</name>
    </proto-grpc-profile>
    <mdt-xfrm>
      <name>JKL</name>
    </mdt-xfrm>
  </mdt-config-data>

NATIVE XML:

<native xmlns="http://cisco.com/ns/yang/Cisco-IOS-XE-native" xmlns:yang="urn:ietf:params:xml:ns:yang:1" yang:operation="none">
    <ip>
      <routing-conf>
        <routing yang:operation="replace" yang:orig-default="false" yang:orig-value="true">false</routing>
      </routing-conf>
    </ip>
    <interface>
      <Vlan>
        <name>23</name>
        <mac-address yang:operation="replace" yang:orig-default="false" yang:orig-value="2C:3F:0B:00:45:11">2C:3F:0B:00:45:C0</mac-address>
      </Vlan>
      <Vlan yang:operation="delete">
        <name>24</name>
        <mac-address>2C:3F:0B:00:45:22</mac-address>
      </Vlan>
      <Vlan yang:operation="none">
        <name>25</name>
        <mac-address yang:operation="create">2C:3F:0B:00:45:25</mac-address>
      </Vlan>
    </interface>
  </native>

[michalvasko]

You should check return values and look at any errors. The behavior you described may be correct so mention what is the behavior you expect and include any error messages.

[rabhat31]

There are no error messages. Could you explain why the behavior may be correct? Why does the native tree in 3 show up as empty even though we've loaded the correct schema. And why does 5 work when I add the LYD_PARSE_ONLY flag and then validate explicitly?

[michalvasko]

Please attach the exact YANG modules with all their imports that you are using. I have tried it with some arbitrary revision and there were unknown nodes in both data trees.

[rabhat31]

We're using the models from https://github.com/YangModels/yang/tree/main/vendor/cisco/xe/17121

[michalvasko]

Fine, please modify my test to reproduce the exact problem you have. It all behaved as expected for me except using only LYD_PARSE_STRICT does not work, you must use at least LYD_VALIDATE_PRESENT so that the data succeed validation and are parsed.