Client: Fix use esp_mqtt_client_enqueue API to send data, data dup flag will be set 1

Author: ESP-YJM

lib/include/mqtt_outbox.h

@@ -54,6 +54,7 @@ int outbox_delete_expired(outbox_handle_t outbox, outbox_tick_t current_tick, ou
 int outbox_delete_single_expired(outbox_handle_t outbox, outbox_tick_t current_tick, outbox_tick_t timeout);
 
 esp_err_t outbox_set_pending(outbox_handle_t outbox, int msg_id, pending_state_t pending);
+pending_state_t outbox_item_get_pending(outbox_item_handle_t item);
 esp_err_t outbox_set_tick(outbox_handle_t outbox, int msg_id, outbox_tick_t tick);
 int outbox_get_size(outbox_handle_t outbox);
 void outbox_destroy(outbox_handle_t outbox);

lib/mqtt_outbox.c

@@ -142,6 +142,14 @@ esp_err_t outbox_set_pending(outbox_handle_t outbox, int msg_id, pending_state_t
     return ESP_FAIL;
 }
 
+pending_state_t outbox_item_get_pending(outbox_item_handle_t item)
+{
+    if (item) {
+        return item->pending;
+    }
+    return QUEUED;
+}
+
 esp_err_t outbox_set_tick(outbox_handle_t outbox, int msg_id, outbox_tick_t tick)
 {
     outbox_item_handle_t item = outbox_get(outbox, msg_id);

mqtt_client.c

@@ -1344,7 +1344,7 @@ static esp_err_t mqtt_resend_queued(esp_mqtt_client_handle_t client, outbox_item
     client->mqtt_state.outbound_message->data = outbox_item_get_data(item, &client->mqtt_state.outbound_message->length, &client->mqtt_state.pending_msg_id,
             &client->mqtt_state.pending_msg_type, &client->mqtt_state.pending_publish_qos);
     // set duplicate flag for QoS-1 and QoS-2 messages
-    if (client->mqtt_state.pending_msg_type == MQTT_MSG_TYPE_PUBLISH && client->mqtt_state.pending_publish_qos > 0) {
+    if (client->mqtt_state.pending_msg_type == MQTT_MSG_TYPE_PUBLISH && client->mqtt_state.pending_publish_qos > 0 && (outbox_item_get_pending(item) == TRANSMITTED)) {
         mqtt_set_dup(client->mqtt_state.outbound_message->data);
     }