MQTT-SN subscriber doesn't receive retained messages on reconnection (independently of QoS of publication or subscription, and independently of the state of the flag CleanSession)

[rodrigoFioravant1]

Expected behavior

A MQTT-SN subscriber that is disconnected should upon reconnection:
Receive the last retained message sent on a topic, regardless if it was sent while the subscriber was or not connected.

The last message because every time a retained message is sent it replaces the previous retained message in the same topic.

Actual behavior

On reconnection the MQTT-SN subscriber does not receives any message. That occurs for both normal (long) and predefined topic types

To Reproduce

Install HiveMQ-Edge

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

Start by subscribing to a topic with a MQTT-SN client

Using a fixed clientID.
Setting both cleanSessio and QoS to either 0 or 1 (same result obtained for all permutations of these values).
./mqtt-sn-java-sub.sh -h 127.0.0.1 -p 2442 -i mqttSN-client-R -t mqttsn/sample/normal/pub/# -q 0

In parallel you can check the behavior subscribing to the same topic using a MQTT client

mosquitto_sub -h 127.0.0.1 -p 1883 -i MQTT-client-R -u artemis -P artemis -t mqttsn/sample/normal/pub/#

While subscribed to the topics publish one message in each topic, both retained, each with a different QoS

mosquitto_pub -h 127.0.0.1 -p 1883 -i MQTT-client-R -u artemis -P artemis -t mqttsn/sample/normal/pub/0 -m "hello world, im normal with qos=0" -q 0 -r
mosquitto_pub -h 127.0.0.1 -p 1883 -i MQTT-client-R -u artemis -P artemis -t mqttsn/sample/normal/pub/1 -m "hello world, im normal with qos=1" -q 1 -r

Disconnect subscriber MQTT-SN

stop mqtt-sn-java-sub.sh

Reconnect subscriber MQTT-SN

./mqtt-sn-java-sub.sh -h 127.0.0.1 -p 2442 -i mqttSN-client-R -t mqttsn/sample/normal/pub/# -q 0
no messages in retained even though it was sent while the client MQTT-SN was subscribed

Reconnect subscriber MQTT

mosquitto_sub -h 127.0.0.1 -p 1883 -i MQTT-client-R -u artemis -P artemis -t mqttsn/sample/normal/pub/#
the retained messages will be present on reconnection

Disconnect subscriber MQTT-SN

stop mqtt-sn-java-sub.sh

Disconnect subscriber MQTT

stop mosquitto_sub

While the subscriber MQTT-SN is disconnected publish one message in each topic

Both messages in retained, each with a different QoS. Different content than the previous publication (it should replace the previous).
mosquitto_pub -h 127.0.0.1 -p 1883 -i MQTT-client-R -u artemis -P artemis -t mqttsn/sample/normal/pub/0 -m "hello world, im normal with qos=0 0" -q 0 -r
mosquitto_pub -h 127.0.0.1 -p 1883 -i MQTT-client-R -u artemis -P artemis -t mqttsn/sample/normal/pub/1 -m "hello world, im normal with qos=1 0" -q 1 -r

Reconnect subscriber MQTT-SN

./mqtt-sn-java-sub.sh -h 127.0.0.1 -p 2442 -i mqttSN-client-R -t mqttsn/sample/normal/pub/# -q 0
no messages in retained

Reconnect subscriber MQTT

mosquitto_sub -h 127.0.0.1 -p 1883 -i MQTT-client-R -u artemis -P artemis -t mqttsn/sample/normal/pub/#
the latest retained messages will be present on reconnection

There are no error logs on the containers image.

Details

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