Check for valid entity pointer in constructSensorTopics()

dcdbpusher/includes/ConfiguratorTemplateEntity.h

@@ -465,11 +465,14 @@ class ConfiguratorTemplateEntity : public ConfiguratorTemplate<SBase, SGroup> {
 		// Sensor names are adjusted according to the respective MQTT topics
 		for (auto &g : _sensorGroups) {
 			for (auto &s : g->acquireSensors()) {
-				s->setMqtt(MQTTChecker::formatTopic(_mqttPrefix) +
-					   MQTTChecker::formatTopic(g->getEntity()->getMqttPart()) +
-					   MQTTChecker::formatTopic(g->getMqttPart()) +
-					   MQTTChecker::formatTopic(s->getMqtt()));
-				s->setName(s->getMqtt());
+				std::string mqtt = MQTTChecker::formatTopic(_mqttPrefix);
+				if (g->getEntity()) {
+					mqtt.append(MQTTChecker::formatTopic(g->getEntity()->getMqttPart()));
+				}
+				mqtt.append(MQTTChecker::formatTopic(g->getMqttPart()));
+				mqtt.append(MQTTChecker::formatTopic(s->getMqtt()));
+				s->setMqtt(mqtt);
+				s->setName(mqtt);
 				SensorMetadata *sm = s->getMetadata();
 				if (sm) {
 					sm->setPublicName(s->getMqtt());