node.getEndpoint call fails sometimes

This appears to be a race condition as it only manifests itself sometimes.

When you call node.getEndpoint, it will throw an exception at some occasions. In the WS server we call this right after “value added” to determine the CC version of the CC belonging to the value. 99% of the times this is OK but sometimes this fails, I believe this happens when interview is still busy ?

Code in the WS server where the exception throws: https://github.com/zwave-js/zwave-js-server/blob/master/src/lib/forward.ts#L142

Capture of the error:

10:52:59.106 DRIVER   Node 28, Endpoint undefined: Trying to access endpoint instance before Multi Channel interview
This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). The promise rejected with the reason:
TypeError: Cannot read property 'getCCVersion' of undefined
    at ZWaveNode.<anonymous> (/usr/lib/node_modules/@zwave-js/server/dist/lib/forward.js:107:56)
    at ZWaveNode.emit (events.js:315:20)
    at ZWaveNode.EventEmitter.emit (domain.js:467:12)
    at ZWaveNode.translateValueEvent (/usr/lib/node_modules/@zwave-js/server/node_modules/zwave-js/src/lib/node/Node.ts:346:8)
    at ValueDB.emit (events.js:315:20)
    at ValueDB.EventEmitter.emit (domain.js:467:12)
    at ValueDB.setValue (/usr/lib/node_modules/@zwave-js/server/node_modules/@zwave-js/core/src/values/ValueDB.ts:224:10)
    at new ConfigurationCCReport (/usr/lib/node_modules/@zwave-js/server/node_modules/zwave-js/src/lib/commandclass/ConfigurationCC.ts:916:22)
    at new CommandClass (/usr/lib/node_modules/@zwave-js/server/node_modules/zwave-js/src/lib/commandclass/CommandClass.ts:108:13)
    at new ConfigurationCC (/usr/lib/node_modules/@zwave-js/server/node_modules/zwave-js/src/lib/commandclass/ConfigurationCC.ts:484:3)

I can simply wrap the call in a try…except or first check if the endpoint is defined but that doesn’t really fix the issue.

[marcelveldt]

Thanks for all the help and insight again. We’re going the safer route and only request all these metadata after the node is ready.

[AlCalzone]

Yeah, the problem here is that the node is sending a multi channel encapsulated command (from an endpoint), which zwave-js emits as a value event, so it doesn’t get missed.

However at that point the Multi Channel CC interview was not completed yet, so zwave-js does not have any information about endpoints yet. You’re trying to read the CC version of that endpoint which is also not known yet at that point, since the endpoint interview happens after the Multi Channel CC interview of the node.

Long story short: The type declarations reflect the error too.

Workaround (I assume your TS version is high enough to support optional chaining):

          args.ccVersion =
-            node.getEndpoint(args.endpoint).getCCVersion(args.commandClass) ||
-            node.getEndpoint(0).getCCVersion(args.commandClass);
+            node.getEndpoint(args.endpoint)?.getCCVersion(args.commandClass) ||
+            node.getCCVersion(args.commandClass);

getEndpoint(0) is also a no-op, it just returns the node instance itself.

I’m not sure how you use these versions, but keep in mind that falling back to the node version in this case can leave you with outdated information after the interview is completed.