Adding extensions to leafnodes using deviation

[srikanthsubbaramu]

Hi Michal,

We are trying to mark a few extensions for some parameters, we could mark this importing the extensions module in the yang file and marking the leaf nodes,
we wanted to understand if we could create module with deviation with which we could add extensions, so rather than modifying multiple yang files we could use a module with deviation to mark extensions, but we see that it fails with unknown prefix error,

here is the extensions yang file

  extension ru-it {
    description
      "Indicates the parameter is modifiable at RU init time only and hence requires a RU restart(reset).";
  }

  extension rt {
    description
      "Indicates the parameter is modifiable at run time and does not require a restart.";
  }

  extension sa {
    description
      "Indicates the parameter is applicable only for standalone deployment.";
  }

  extension nsa {
    description
      "Indicates the parameter is applicable only for non standalone deployment.";
  }

  extension sa-nsa {
    description
      "Indicates the parameter is applicable only for both standalone and non standalone deployment.";
  }

  extension spec-ref {
    description
      "Specify the specification reference if the parameter is taken from any specification.";
    argument "spec-ref";
  }

}

We are trying to use it via deviate,

module _ran-nr-nrm-gnbcucp-ext-test {
  yang-version 1.1;
  namespace "urn:3gpp:sa5:_ran-nr-nrm-gnbcucp-ext-test";
  prefix "gnbcucp-ext-test";

  import _3gpp-common-managed-element { prefix me3gpp; }
  import _3gpp-nr-nrm-gnbcucpfunction { prefix gnbcucp3gpp; }
  import _ran-nr-nrm-yang-extensions { prefix yextran; }

  deviation "/me3gpp:ManagedElement/gnbcucp3gpp:GNBCUCPFunction/gnbcucp3gpp:attributes/gnbcucp3gpp:gNBId" {
    deviate add {
      yextran:rt;
    }
  }
}

when we try to load the yang in sr_install_module , with verbose log i am seeing below

[VRB] Searching for "_3gpp-nr-nrm-gnbcucpfunction" in "/opt/sysrepo/yang".
[VRB] Loading schema from "/tmp/yangs/_3gpp-nr-nrm-gnbcucpfunction.yang" file.
[ERR] Invalid prefix "yextran" used for extension instance identifier.
[2026-03-17 09:17:14.082575] [INFO] Extension module install failed: libyang error
[2026-03-17 09:17:14.082595] [INFO] Session stopped.
[INF] Connection 1 destroyed.

we need to understand if we can add extensions via deviate,

Thanks,
Srikanth

[michalvasko]

Works just fine in a test I have just added, maybe you are using an old libyang version.

[srikanthsubbaramu]

Hi Michal,
we are on libyang-devel branch which is 3 weeks old from current devel branch .

Thanks,
Srikanth

[michalvasko]

Then provide all the required YANG modules including the import so that I can reproduce it.

[srikanthsubbaramu]

yangs.zip
command used for loading is
rc = sr_install_modules(conn, schema_paths.data(), search_dir, NULL);
const char *search_dir = "/opt/sysrepo/yang:/tmp/yangs"; ( /opt/sysrepo is sysrepodir ) /tmp/yangs is hwere above yangs are extracted, and schema_paths is array of all filenames in yang