Merge pull request #47401 from NeatGuyCoding

* pr/47401:
  Polish "Validate node configuration with static master replica"
  Validate node configuration with static master replica

Closes gh-47401

Author: snicoll

module/spring-boot-data-redis/src/main/java/org/springframework/boot/data/redis/autoconfigure/DataRedisConnectionConfiguration.java

@@ -154,6 +154,7 @@ protected final RedisStandaloneConfiguration getStandaloneConfig() {
 		}
 		if (this.connectionDetails.getMasterReplica() != null) {
 			List<Node> nodes = this.connectionDetails.getMasterReplica().getNodes();
+			Assert.state(!nodes.isEmpty(), "At least one node is required for master-replica configuration");
 			RedisStaticMasterReplicaConfiguration config = new RedisStaticMasterReplicaConfiguration(
 					nodes.get(0).host(), nodes.get(0).port());
 			nodes.stream().skip(1).forEach((node) -> config.addNode(node.host(), node.port()));

module/spring-boot-data-redis/src/test/java/org/springframework/boot/data/redis/autoconfigure/DataRedisAutoConfigurationTests.java

@@ -500,6 +500,15 @@ void testRedisConfigurationWithClusterAndAuthentication() {
 			});
 	}
 
+	@Test
+	void testRedisConfigurationWithMasterReplicaAndNoNode() {
+		this.contextRunner.withPropertyValues("spring.data.redis.masterreplica.nodes=")
+			.run((context) -> assertThat(context).hasFailed()
+				.getFailure()
+				.rootCause()
+				.hasMessage("At least one node is required for master-replica configuration"));
+	}
+
 	@Test
 	void testRedisConfigurationWithMasterReplica() {
 		this.contextRunner