_MQTT_AVAILABILITY_TOPIC_LEGACY does not work with will_set

[phbasler]

Hi @fphammerle

I just saw the fix with MQTT_AVAILABILITY_TOPIC_LEGACY because of the "" to "-" mixup.

In

switchbot-mqtt/switchbot_mqtt/__init__.py

Lines 101 to 106 in 9947875

	for topic in (_MQTT_AVAILABILITY_TOPIC, _MQTT_AVAILABILITY_TOPIC_LEGACY):
	mqtt_client.will_set(
	topic=mqtt_topic_prefix + topic,
	payload=_MQTT_LAST_WILL_PAYLOAD,
	retain=True,
	)

you have the for loop which calls will_set twice. While this does not give you an error, it does not work as expected. If you call will_set, it overrides the old will. So in this case the Will is only for the _MQTT_AVAILABILITY_TOPIC_LEGACY and not for _MQTT_AVAILABILITY_TOPIC. You can only have one will in mqtt.

A possible workaround would be to have a second mqtt client which just has the will and the birth message to the legacy topic and have the original client have the non legacy topic.

But practically spoken: Why not declare it as a bug and make version 3.3.1 with the corrected topic?

[fphammerle]

Thanks a lot, @phbasler, for following up and reviewing my changes!

After realizing that I had a mismatch between code and docs in v3.3.0, I was hoping that I could avoid a breaking change that way (but missed to check the docs or properly test the change).

I will follow your suggestion and call it a "fix" rather than a "change".

[fphammerle]

released: https://pypi.org/project/switchbot-mqtt/3.3.1/

[phbasler]

No problem, I'm just happy that it now works to have a template switch which can decide by itself if it should signal a satellite pi zero to control the switchbot or the server itself if the pi zero is not online.