Reproducer attempt for https://github.com/lettuce-io/lettuce-core/issues/905

DemoApplication.java

package com.example.demo;

import org.springframework.data.redis.core.RedisTemplate;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.redis.core.ReactiveRedisTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import reactor.util.function.Tuples;

@SpringBootApplication
public class DemoApplication {

	@Autowired ReactiveRedisTemplate<Object, Object> template;

	public static void main(String[] args) {
		SpringApplication.run(DemoApplication.class, args);
	}

	@PostConstruct
	private void postConstruct() {

		for (int i = 0; i < 4; i++) {

			template.opsForHash().put("master-key", "entry-" + i, "use-key-" + i).subscribe();
			template.opsForValue().set("use-key-" + i, "the value " + i).subscribe();
		}
	}
	
	@RestController
	static class ReactiveController {

		@Autowired ReactiveRedisTemplate<Object, Object> template;

		@GetMapping("/")
		public Mono<Object> get() {

			return template.<String, String> opsForHash().get("master-key", "entry-1")
					.zipWith(template.<String, String> opsForHash().get("master-key", "entry-2")).flatMap(t -> {

						return template.opsForValue().get(t.getT1()).zipWith(template.opsForValue().get(t.getT2()));
					});
		}
	}
	
	//@RestController
	static class SynchronousController {

		@Autowired RedisTemplate<Object, Object> template;

		@GetMapping("/")
		public Object get() {

			String entry1 = template.<String, String>opsForHash().get("master-key", "entry-1");
			String entry2 = template.<String, String> opsForHash().get("master-key", "entry-2");
			Object v1 = template.opsForValue().get(entry1);
			Object v2 = template.opsForValue().get(entry2);

			return Tuples.of(v1, v2);
		}
	}
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.example</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>demo</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.0.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-redis</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-redis-reactive</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-webflux</artifactId>
		</dependency>

		<dependency>
			<groupId>io.lettuce</groupId>
			<artifactId>lettuce-core</artifactId>
			<version>5.1.3.BUILD-SNAPSHOT</version>
		</dependency>
		 <!--
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-pool2</artifactId>
		</dependency>-->

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>io.projectreactor</groupId>
			<artifactId>reactor-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>


</project>