Fix broker session persistence and nonblocking CONTINUE handling

[aidangarske]

F-10334, F-10338, F-10336, F-10331, F-10335

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Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

Suppressed comments (2)

src/mqtt_broker.c:5512

• sub->client->connack_pending_len is referenced inside the WOLFMQTT_V5 QoS0 path, but the BrokerClient member is excluded under WOLFMQTT_STATIC_MEMORY. This will not compile for v5 + static-memory configurations.

            /* QoS 0 is best effort; skip while tx_buf holds an in-flight
             * CONNACK. */
            else if (sub->client->connack_pending_len == 0)
#endif
            {

src/mqtt_sn_client.c:2163

• In WOLFMQTT_NONBLOCK, MqttPacket_Write() can return MQTT_CODE_CONTINUE for a partial send. This function currently treats any rc != client->write.len as a failure (and in multithread mode removes the pending response), but it does not track a send-in-progress state (e.g., MQTT_MSG_HEADER) like other MQTT-SN flows in this file (see SN_WillTopic). This can cause retries to re-add/remove the pending response incorrectly and lose the ability to safely resume the in-flight write.

        /* Send disconnect packet */
        rc = MqttPacket_Write(client, client->tx_buf, client->write.len);
        if (rc != client->write.len) {
        #ifdef WOLFMQTT_MULTITHREAD
            wm_SemUnlock(&client->lockSend);