[netmod] IEEE Std 802.1Qcw invalidates trivial YANG data tree

[Florian Kauer <[e-mail]>]

Hi,
I know this is bad timing since Qcw was just published, but - at least with libyang - the following YANG data tree that specifies nothing Qcw related is no longer valid when just loading the Qcw YANG models:

interface.json:
{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "if-index": 1,
        "name": "eth0",
        "type": "iana-if-type:ethernetCsmacd",
        "oper-status": "down",
        "admin-status": "down",
        "statistics": {
          "discontinuity-time": "2023-12-15T10:04:12.345+00:00"
        }
      }
    ]
  }
}

yanglint interface.json ieee802-dot1q-sched.yang ieee802-dot1q-sched-bridge.yang ieee802-types.yang ieee802-dot1q-types.yang ieee802-dot1q-bridge.yang [e-mail] [e-mail]

results into

libyang err : Number of elements in admin-control-list must not be greaterthan supported-list-max (Data location "/ietf-interfaces:interfaces/interface[name='eth0']/ieee802-dot1q-bridge:bridge-port/ieee802-dot1q-sched-bridge:gate-parameter-table/admin-control-list".)
libyang err : Number of elements in oper-control-list must not be greaterthan supported-list-max (Data location "/ietf-interfaces:interfaces/interface[name='eth0']/ieee802-dot1q-bridge:bridge-port/ieee802-dot1q-sched-bridge:gate-parameter-table/oper-control-list".)
libyang err : admin-cycle-time must not be greater than supported-cycle-max (Data location "/ietf-interfaces:interfaces/interface[name='eth0']/ieee802-dot1q-bridge:bridge-port/ieee802-dot1q-sched-bridge:gate-parameter-table/admin-cycle-time".)
libyang err : oper-cycle-time must not be greater than supported-cycle-max (Data location "/ietf-interfaces:interfaces/interface[name='eth0']/ieee802-dot1q-bridge:bridge-port/ieee802-dot1q-sched-bridge:gate-parameter-table/oper-cycle-time".)
YANGLINT[E]: Failed to parse input data file "interface.json".

My first expectation was a bug in libyang, but Michal is convinced that libyang's behavior is correct in this regard:
https://github.com/CESNET/libyang/issues/2140

I have not enough experience in YANG to properly argue if either the YANG model or libyang needs to be changed, but I don't think we want to force every interface to specify a
/ietf-interfaces:interfaces/interface[name='eth0']/ieee802-dot1q-bridge:bridge-port/ieee802-dot1q-sched-bridge:gate-parameter-table/supported-list-max
etc. just because the Qcw YANG models are loaded.

I hope I have just a misunderstanding and I am looking forward to your responses!

Greetings,
Florian