Matter: composed device types are re-registered on every restart, changing the bridged device's uniqueId #4018

Analysis

If a plugin composes its own device type (e.g. TemperatureSensor.with(HumiditySensor.behaviors.relativeHumidityMeasurement)), Homebridge replaces the accessory on every restart, and the new endpoint gets a new random BridgedDeviceBasicInformation.uniqueId.

• The Matter cache stores the device type as { name, code } only, so the restore rebuilds the base type.
• When the plugin registers again, sameShape in AccessoryManager.registerAccessory() compares behavior keys, finds that they differ, logs changed structure - re-registering and recreates the endpoint.
• The endpoint number survives, but uniqueId is regenerated. Plugins can't pin it: createEndpointOptions() doesn't pass one through.

So a controller that identifies bridged devices by uniqueId may see a new device after every restart. A plain type, or a BridgedNode with parts, is attached in place and keeps its uniqueId.

Related: #4015 (same re-registration path).

Expected Behavior

Restarting without any plugin change keeps the bridged device's uniqueId the same.

Steps To Reproduce

1. npm i homebridge@2.4.0
2. Save the script below as repro.mjs next to node_modules.
3. Run node repro.mjs twice with the same matter-store.
4. The endpoint number stays the same; uniqueId changes on every run after the first, which logs changed structure - re-registering.

import { MatterServer } from "./node_modules/homebridge/dist/matter/server.js";
import { deviceTypes } from "./node_modules/homebridge/dist/matter/index.js";
import { uuid } from "@homebridge/hap-nodejs";

const { TemperatureSensor: T, HumiditySensor: H } = deviceTypes;
const server = new MatterServer({ port: 5597, uniqueId: "REPRO", storagePath: process.cwd() + "/matter-store" });
await server.start();
const UUID = uuid.generate("repro");
await server.registerPlatformAccessories("p", "P", [{
  UUID, displayName: "Sensor", serialNumber: "1", manufacturer: "x", model: "y",
  deviceType: T.with(H.behaviors.relativeHumidityMeasurement),
  clusters: {
    temperatureMeasurement: { measuredValue: null, minMeasuredValue: -5000, maxMeasuredValue: 10000 },
    relativeHumidityMeasurement: { measuredValue: null, minMeasuredValue: 0, maxMeasuredValue: 10000 },
  },
}]);
const ep = server.accessories.get(UUID).endpoint;
console.log("number:", ep.number, "uniqueId:", ep.state.bridgedDeviceBasicInformation.uniqueId);
await server.stop();

Logs

run 1: number: 2 uniqueId: 6o1E3j2yGbKNS5ir3aKHA0DJzovYSMpi
run 2: number: 2 uniqueId: cmZF382QA2i3cMWntwIohVBMblNifXYo   (logged "changed structure - re-registering")
run 3: number: 2 uniqueId: ZKbotzSvG3cdRJRkXD5GPg8Wbd2j1oBJ   (logged "changed structure - re-registering")

Same on a child bridge with a real plugin:
[Matter/Server] Restored accessory Temperature & Humidity changed structure - re-registering
[Matter/Server] Unregistered Matter accessory: Temperature & Humidity (adc34eaf-43a1-4e71-83db-cad86f0eb7e4)
[Matter/Server] Registered Matter accessory: Temperature & Humidity (adc34eaf-43a1-4e71-83db-cad86f0eb7e4)

Configuration

{
  "platform": "HygrotermographCGDK2",
  "_bridge": {
    "username": "0E:D8:3D:82:7E:70",
    "port": 35144,
    "matter": { "port": 5531 }
  }
}

Environment

• OS: Debian GNU/Linux 12 (bookworm), Raspberry Pi
• Software: Homebridge 2.4.0 (Matter.js 0.17.9); same logic in 2.4.1-beta.11
• Node: 24.21.0
• npm: 11.19.0

Process Supervisor

hb-service

Additional Context

Use case: a temperature + humidity sensor on one endpoint. IKEA Dirigera lists every sensor endpoint as a separate product, so this is the only layout it shows as one device (plugin: @thecloudseeker/homebridge-hygrothermograph-cgdk2).

Possible fixes:

1. Carry the uniqueId over from the endpoint being replaced (or derive it from the accessory UUID).
2. Treat a plugin type that only adds behaviors to the restored base type as the same shape, so it's attached in place.