MQTT not reconnecting if only only one mqtt node using it

General
1

Could someone confirm an apparent bug that I am seeing please?

Starting with an empty flows file, configure a single MQTT In node (subscribing to a fixed topic) and a broker and deploy. Check it is working.

Change the topic subscribed to and do a partial deploy. On two systems here I am seeing that it disconnects and does not reconnect.

A Restart Flows fixes it.

If a second MQTT In node, using the same broker config, is added then the problem does not occur.

I am using node-red 3.0.2 and see this with node.js 16 and 18.

2

Confirmed on an alternate installer install
image

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Indeed, doing exaclty like you said results in node not connecting after the partial deploy. Now, when i configure something as the close message this issue will not happen. Same for the will message.

4

Thanks both for testing, I will submit an issue.
It is amazing how a fundamental bug like that can go unnoticed, presumably for months if not longer.

1 Like
5

Well - its a fairly niche edge case :slight_smile:

6

I suspect beginners will have fallen over it in their initial fiddling with MQTT but just assumed it was something they were doing wrong, then as soon as you add another MQTT node it goes away.

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