Field 'value' might be missing on 'currentValue' message

[s-frei]

Hi there,

first of all I really appreaciate your good work you are doing here, and to
see the progress over the last years! 🚀 Keep up the good work.

---

Now to the problem I encountered just recently. I'm deserializing the Entire Z-Wave value Object messages
to corresponding Java objects. I've unit tested those deserializations with real collected messages using v5.8.0.
The type field in the messages are giving me a hint what type of object I could expect, parsing the value.

This works well for a message like (used in unit test):

{
  "id": "3-38-1-currentValue",
  "nodeId": 3,
  "commandClass": 38,
  "commandClassName": "Multilevel Switch",
  "endpoint": 1,
  "property": "currentValue",
  "propertyName": "currentValue",
  "type": "number",
  "readable": true,
  "writeable": false,
  "label": "Current value",
  "stateless": false,
  "min": 0,
  "max": 99,
  "list": false,
  "value": 99,
  "isCurrentValue": true,
  "targetValue": "38-1-targetValue",
  "lastUpdate": 1627285239197
}

Today I got some stacktraces on deserializing messages sent with v6.12.0. Example of failing message:

{
  "id": "3-38-2-currentValue",
  "nodeId": 3,
  "commandClass": 38,
  "commandClassName": "Multilevel Switch",
  "endpoint": 2,
  "property": "currentValue",
  "propertyName": "currentValue",
  "type": "number",
  "readable": true,
  "writeable": false,
  "label": "Current value",
  "stateless": false,
  "commandClassVersion": 4,
  "min": 0,
  "max": 99,
  "list": false,
  "isCurrentValue": true,
  "targetValue": "38-2-targetValue",
  "lastUpdate": 1656661337621
}

because the value field is missing there. Is it expectable that this field might be missing from now on?
Is this related to the change made here d437d5e?

The actual used device:

Manufacturer	Product	Product code
Fibargroup	Roller Shutter 3	FGR223

Couldn't find anything more specific about this behaviour and wasn't sure if this should be an issue.

If you need more information, additional data, and so on, let me know. I'll try to response as fast as
possible 🙂

[robertsLando]

@s-frei version 5.8 is from 8 months ago, lot of things have changed in the meanwhile

because the value field is missing there. Is it expectable that this field might be missing from now on?

The value shouldn't be missing, at least I didn't change that part of code that handles it: https://github.com/zwave-js/zwavejs2mqtt/blob/master/lib/Gateway.ts#L1805

Does the value is ALWAYS missing or just sometime? Did you tried to change the payload type to see if value is present with JSON/Raw type?

[s-frei]

Ok, refreshing the Multilevel Switch CC did the job:

zwavejs2mqtt    | 14:54:20.783 CNTRLR �� [Node 003] requesting current switch state...                     [Endpoint 1]
zwavejs2mqtt    | 2022-07-01 14:54:21.250 INFO ZWAVE: Node 3: value updated: 38-1-targetValue 90 => 90
zwavejs2mqtt    | 2022-07-01 14:54:21.255 INFO ZWAVE: Node 3: value updated: 38-1-duration unknown => unknown
zwavejs2mqtt    | 2022-07-01 14:54:21.258 INFO ZWAVE: Node 3: value updated: 38-1-currentValue 90 => 90
zwavejs2mqtt    | 14:54:21.269 CNTRLR �� [Node 003] requesting current switch state...                     [Endpoint 2]
zwavejs2mqtt    | 2022-07-01 14:54:21.703 INFO ZWAVE: Node 3: value updated: 38-2-targetValue 10 => 99
zwavejs2mqtt    | 2022-07-01 14:54:21.710 INFO ZWAVE: Node 3: value added: 38-2-duration => unknown
zwavejs2mqtt    | 2022-07-01 14:54:21.711 INFO ZWAVE: Node 3: value added 3-38-2-duration => unknown
zwavejs2mqtt    | 2022-07-01 14:54:21.714 INFO ZWAVE: Node 3: value added: 38-2-currentValue => 99
zwavejs2mqtt    | 2022-07-01 14:54:21.773 INFO ZWAVE: Node 3: value added 3-38-2-currentValue => 99
zwavejs2mqtt    | 2022-07-01 14:54:21.782 INFO ZWAVE: Success zwave api call refreshCCValues undefined

thank you for your help.

Maybe it would be an improvement always having a value field (nullish), even though it hasn't got a value.

[robertsLando]

Maybe it would be an improvement always having a value field (nullish), even though it hasn't got a value.

Values should never be undefined, if so it means there is an error that should be fixed (like with a refresh). This could happen maybe when driver is updated and there is some kind of inconsistency in cache. Nothing so bas BTW

[s-frei]

My intention here was to keep the API (JSON via MQTT) consistent and stick to the displayed value on the UI.
It's always nice to know exactly what to expect. We've got multiple gateways, so maybe I need to implement the refreshInfo(nodeId) API.

But anyhow, thank you for your help on this one! If you want to, let me know if I/we could help you somewhere and I'll try to get some time for this. Maybe something UI or doumentation related 🙂

[robertsLando]

the problem is that when a value is undefined in a JS object and you convert it to JSON string to send as MQTT payload it will strip out undefined props, I could set it to null to prevent it if needed

[s-frei]

I see... For me it's okay that the value might be missing and I'm able to handle this correctly now. I don't know the impact of adding the field with a null value when it can't be determined, for others. I personally think this would be a good idea since it makes clear what the currentValue is, even though it's 'nothing'. This could als be an optional feature on the Gateway settings.