MQTT-SN subscriber doesn't receive any messages after a reconnection (clean session disabled and QOS=1 for messages)

[marcoratto]

Expected behavior

If a subscriber disconnected from a MQTT-SN Broker, it should receive all messages sent during the disconnection period once it reconnects.
According to the specification MQTT-SN_spec_v1.2.pdf, page 22:

6.3 Clean session
With MQTT, when a client disconnects, its subscriptions are not deleted. They are persistent and valid for new
connections, until either they are explicitly un-subscribed by the client, or the client establishes a new connection
with the “clean session” flag set.
In MQTT-SN the meaning of a “clean session” is extended to the Will feature, i.e. not only the subscriptions
are persistent, but also the Will topic and the Will message.

Actual behavior

MQTT-SN subscriber doesn't receive any messages.

To Reproduce

Step 0: Run HiveMQ Edge on a Docker Container

docker pull hivemq/hivemq-edge
docker run --name hivemq-edge -d -p 1883:1883 -p 8080:8080 -p 2442:2442/udp hivemq/hivemq-edge

Step 1: Subscribe to an MQTT topic

mosquitto_sub -h 127.0.0.1 -p 1883 -c -i mqtt-client-sub -t mqttsn/sample/normal -q 1

clean session disabled, QOS=1 and ClientID fixed

Step 2: Subscribe to an MQTT-SN normal topic

mqtt-sn-sub -h 127.0.0.1 -p 2442 -c -q 1 -i mqttsn-client-sub -t mqttsn/sample/normal

clean session disabled, QOS=1 and ClientID fixed

Step 3: send a message on MQTT topic

mosquitto_pub -h 127.0.0.1 -p 1883 -t mqttsn/sample/normal -m "hello 1" -q 1

Step 4: send a message on MQTT topic

mosquitto_pub -h 127.0.0.1 -p 1883 -t mqttsn/sample/normal -m "hello 2" -q 1

Step 5: Stop MQTT subscriber

Stop mosquitto_sub

Step 6: Stop MQTT-SN Subscriber

Stop mqtt-sn-sub

Step 7: send a message on MQTT topic

mosquitto_pub -h 127.0.0.1 -p 1883 -t mqttsn/sample/normal -m "hello 3" -q 1

Step 8: send a message on MQTT topic

mosquitto_pub -h 127.0.0.1 -p 1883 -t mqttsn/sample/normal -m "hello 4" -q 1

Step 9: Subscribe again to an MQTT topic

mosquitto_sub -h 127.0.0.1 -p 1883 -c -i mqtt-client-sub -t mqttsn/sample/normal -q 1

Receive correctly messages "hello 3" and "hello 4"

Step 10: Subscribe again to an MQTT-SN normal topic (ERROR)

mqtt-sn-sub -h 127.0.0.1 -p 2442 -c -q 1 -i mqttsn-client-sub -t mqttsn/sample/normal

It doesn't receive any messages.
No error log on container image.

Reproducer code

n/a

Details

• Affected HiveMQ Edge version(s): 2024.9
• Used JVM version: Internal of the container

[sfrehse]

Thanks for reporting and the detailed description. We will track this more detailed internally to work on that.