Empty groups.yml: "TypeError: Cannot convert undefined or null to object" during interviewing

[rhuss]

What happened?

When trying to pair a Aqara RTCGQ11LM motion sensor I get the following error when trying to pair:

TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at /app/lib/util/settings.ts:241:50
    at Array.map (<anonymous>)
    at writeDevicesOrGroups (/app/lib/util/settings.ts:241:22)
    at write (/app/lib/util/settings.ts:251:5)
    at Object.addDevice (/app/lib/util/settings.ts:560:5)
    at Device.ensureInSettings (/app/lib/model/device.ts:42:22)
    at Zigbee.resolveDevice (/app/lib/zigbee.ts:247:20)
    at Controller.<anonymous> (/app/lib/zigbee.ts:91:33)
    at Controller.emit (node:events:517:28)

After that the server stops. After restart I see the following in the logs

Zigbee2MQTT:info  2023-12-18 21:25:05: 0x00158d000a832619 (0x00158d000a832619): Not supported (Unknown)
....
Zigbee2MQTT:warn  2023-12-18 21:28:20: Received message from unsupported device with Zigbee model 'undefined' and manufacturer name 'undefined'
Zigbee2MQTT:warn  2023-12-18 21:28:20: Please see: https://www.zigbee2mqtt.io/advanced/support-new-devices/01_support_new_devices.html

What did you expect to happen?

I expect that pairing either works without problem or a clear error message appears, without crashing the server.

How to reproduce it (minimal and precise)

Just pair an Aqara RTCGQ11LM

Zigbee2MQTT version

1.34.0-dev (commit #29635a9)

Adapter firmware version

20230507

Adapter

Slaesh's CC2652

Debug log

No extra logs except that stacktrace pasted above.

[rhuss]

Side note: I'm using multiple device.yml files, one for read-write and the others read-only (they are served from a ConfigMap in Kubernetes). My configuration looks like:

# Use different files for devices and groups
# Comment out the next line temporarily on rw errors:
devices:
  - devices-run.yaml
  - devices.yaml
#devices: devices.yaml
groups:
  - groups-run.yaml
  - groups.yaml

[rhuss]

devices-run.yaml contains a YAML map, groups-run.yaml contains an empty map ({})

[rhuss]

It turned out, that groups.yaml contained only comments, so that yaml.load(...) probably returned null. That then caused that exception.

If I add an empty {} to the groups.yaml, everything's fine. Maybe one can make that a bit more robust ?

[rhuss]

Fixed with #20289