DATAREDIS-1093 - Document that Master/Replica connections do not support Pub/Sub.

src/main/java/org/springframework/data/redis/connection/RedisStaticMasterReplicaConfiguration.java

@@ -27,6 +27,7 @@ import org.springframework.util.Assert;
  * Master / Replica configuration to nodes know to not change address. Eg. when connecting to
  * <a href="https://aws.amazon.com/documentation/elasticache/">AWS ElastiCache with Read Replicas</a>. <br/>
  * Note: Redis is undergoing a nomenclature change where the term replica is used synonymously to slave.
+ * Please also note that a Master/Replica connection cannot be used for Pub/Sub operations.
  *
  * @author Mark Paluch
  * @author Christoph Strobl

src/main/java/org/springframework/data/redis/connection/lettuce/StaticMasterReplicaConnectionProvider.java

@@ -22,6 +22,7 @@ import io.lettuce.core.api.StatefulConnection;
 import io.lettuce.core.codec.RedisCodec;
 import io.lettuce.core.masterreplica.MasterReplica;
 import io.lettuce.core.masterreplica.StatefulRedisMasterReplicaConnection;
+import io.lettuce.core.pubsub.StatefulRedisPubSubConnection;
 
 import java.util.Collection;
 import java.util.Optional;
@@ -70,6 +71,10 @@ class StaticMasterReplicaConnectionProvider implements LettuceConnectionProvider
 	@Override
 	public <T extends StatefulConnection<?, ?>> T getConnection(Class<T> connectionType) {
 
+		if (connectionType.equals(StatefulRedisPubSubConnection.class)) {
+			throw new UnsupportedOperationException("Pub/Sub connections not supported with Master/Replica configurations");
+		}
+
 		if (StatefulConnection.class.isAssignableFrom(connectionType)) {
 
 			StatefulRedisMasterReplicaConnection<?, ?> connection = MasterReplica.connect(client, codec, nodes);