CacheErrorHandler doesn't work for Cacheable when sync=true for Redis

[adamcamp]

When using the @Cacheable annotation with sync=true parameter, the exceptions are thrown without calling the CacheErrorHandler for underlying cache issues.

**Expected behavior: ** Below code prints "Test Passed" and exit code is 0, logging the connection failure to Redis.

**Actual behavior: ** Below code throws connection exception, never logs the message, and exit code is 1.

@SpringBootApplication
@EnableCaching
public class DemoApplication implements CachingConfigurer {

	@Override
	public CacheErrorHandler errorHandler() {
		return new LoggingCacheErrorHandler(true);
	}
	
	@Cacheable(value="test", sync=true)
	public String cacheTest(String test) {
		return test;
	}
	
	public static void main(String[] args) {
		ApplicationContext context = SpringApplication.run(DemoApplication.class, args);
		
		System.out.println(context.getBean(DemoApplication.class).cacheTest("Test Passed"));
	}
}

If we change the sync=true to sync=false then the code works as expected, but when sync=true it fails and never calls the error handler.

[mhalbritter]

Duplicate of spring-projects/spring-framework#21590.