state node seems to crash node red server

[SirYaro]

On my NR deployment as below:

1 Oct 00:34:49 - [info] Node-RED version: v3.1.5
1 Oct 00:34:49 - [info] Node.js  version: v18.19.0
1 Oct 00:34:49 - [info] Linux 6.6.16-haos x64 LE
1 Oct 00:34:51 - [info] Loading palette nodes
1 Oct 00:34:52 - [info] Node-RED Contrib Theme Collection version: v3.1.9
1 Oct 00:34:59 - [info] Dashboard version 3.6.2 started at /endpoint/ui

I set up a simple flow:

[{"id":"aa81c317a725a8f3","type":"set-shared-state","z":"8e8f5a68f5eb9b9d","g":"b01913e064169ca1","state":"7ea309fdc0ceb6d8","name":"yaro_swiatlo_lewy","triggerOnInit":true,"triggerOnChange":true,"provideOutput":false,"outputs":0,"x":470,"y":4500,"wires":[]},{"id":"3b86614cbf559f9d","type":"mqtt in","z":"8e8f5a68f5eb9b9d","g":"b01913e064169ca1","name":"przełacznik ","topic":"zigbee2mqtt/wlacznik-2klik-C-warsztat","qos":"2","datatype":"auto-detect","broker":"224853ed.7c89fc","nl":false,"rap":true,"rh":0,"inputs":0,"x":100,"y":4500,"wires":[["c66f5b9c7ee8bcbe"]]},{"id":"67c2c43140b7ee2a","type":"debug","z":"8e8f5a68f5eb9b9d","g":"b01913e064169ca1","name":"debug 49","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":460,"y":4560,"wires":[]},{"id":"c66f5b9c7ee8bcbe","type":"function","z":"8e8f5a68f5eb9b9d","g":"b01913e064169ca1","name":" ","func":"\nreturn msg.payload;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":270,"y":4500,"wires":[["aa81c317a725a8f3","67c2c43140b7ee2a"]]},{"id":"7ea309fdc0ceb6d8","type":"shared-state","name":"yaro_swiatlo_lewy","lbl":"","tags":"yaro,włacznik,lewy","historyCount":"2","dataType":"obj","boolType":"bool","boolStrTrue":"","boolStrFalse":"","precision":"","numMin":"","numMax":"","unit":"","saveInterval":"0"},{"id":"224853ed.7c89fc","type":"mqtt-broker","name":"HA MQTT","broker":"localhost","port":"1883","clientid":"node-red","autoConnect":true,"usetls":false,"compatmode":false,"protocolVersion":"4","keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","birthMsg":{},"closeTopic":"","closeQos":"0","closePayload":"","closeMsg":{},"willTopic":"","willQos":"0","willPayload":"","willMsg":{},"userProps":"","sessionExpiry":""}]

When "mqtt in" node sends a message similar to this:

{"topic":"zigbee2mqtt/wlacznik-2klik-C-warsztat","payload":{"action":null,"device_temperature":23,"flip_indicator_light":"ON","flip_indicator_light_left":"ON","linkquality":232,"mode_switch":null,"operation_mode_left":null,"operation_mode_right":null,"power_outage_count":4,"power_outage_memory":null,"state_left":"OFF","state_right":"OFF","update":{"installed_version":-1,"latest_version":-1,"state":null},"update_available":null},"qos":0,"retain":false,"_topic":"zigbee2mqtt/wlacznik-2klik-C-warsztat","_msgid":"4b9575a56a9036e3"}

It always crashed my NR server with below exception.
It also crash it during restart attempt but approximately only about 5 times out of 6 attempts.

1 Oct 00:30:14 - [red] Uncaught Exception:
1 Oct 00:30:14 - [error] SyntaxError: Unexpected token u in JSON at position 0
    at JSON.parse (<anonymous>)
    at stateNode.update (/config/node_modules/node-red-contrib-state/lib/state.js:137:23)
    at setStateNode._inputCallback (/config/node_modules/node-red-contrib-state/lib/setState.js:47:24)
    at /opt/node_modules/@node-red/runtime/lib/nodes/Node.js:214:26
    at Object.trigger (/opt/node_modules/@node-red/util/lib/hooks.js:166:13)
    at setStateNode.Node._emitInput (/opt/node_modules/@node-red/runtime/lib/nodes/Node.js:206:11)
    at setStateNode.Node.emit (/opt/node_modules/@node-red/runtime/lib/nodes/Node.js:190:25)
    at setStateNode.Node.receive (/opt/node_modules/@node-red/runtime/lib/nodes/Node.js:499:10)
    at deliverMessageToDestination (/opt/node_modules/@node-red/runtime/lib/flows/Flow.js:800:40)
    at Immediate.<anonymous> (/opt/node_modules/@node-red/runtime/lib/flows/Flow.js:816:21)
[00:30:14] INFO: Service Node-RED exited with code 1 (by signal 0)

[lorenwest]

The problem is your state file on disk is corrupt. You will need to either manually fix the file or remove it completely.

The offending line is this one:

node-red-contrib-state/lib/state.js

Line 150 in 61e3964

await writeFile(node.stateFile, JSON.stringify(node.exposedState()));

If the process fails during the write of that file, it can leave it in a partially saved (corrupt) state.

If anyone is willing to make an improvement to this library, a good FS save change would be to write the state to a temporary file, then move that file into place. The move is autonomous - it either works 100% or fails 100%, so it won't leave a file in a partially saved state.

Leaving open for discussion if anyone wants to make this improvement.

[lorenwest]

Another improvement would be to add error handling on the FS.readFile side so it doesn't crash Node-RED if it tries to load a corrupt file. It wouldn't read the file, but at least it wouldn't crash Node-RED.

[SirYaro]

Is it possible that the incoming message was somehow "wrong", and could not be parsed and saved? Because that's how it looked from my side.
I was tinkering with the function node and when I put there a certain return message everything went to hell. :)
When I changed function code, it fixed the problem immediately.