nested exception is java.lang.UnsupportedOperationException: io.lettuce.core.output.ValueOutput does not support set(long)

[Memorydoc]

Our service encountered ValueOutput does not support set(long) exception, which was automatically recovered after service restart. Strange scenario. How do we solve this?

[tishun]

Hey @Memorydoc ,
from the exception name (org.springframework.data.redis.RedisSystemException) I can only assume you are having issue with the Spring Data Redis and not the Lettuce driver itself?

Anyway to understand the issue better we will need more information like a complete stacktrace or a sample of the code that ptoduces this issue.

[ShepherdZFJ]

I encountered the same problem when upgrading from Spring boot2.3.4 to 2.7.0
The code example is as follows：

   @Test
    public void test() {
        StringBuilder lua = new StringBuilder();
        lua.append("local c");
        lua.append("\nc = redis.call('get',KEYS[1])");
        lua.append("\nif c and tonumber(c) > tonumber(ARGV[1]) then");
        lua.append("\nreturn c;");
        lua.append("\nend");
        lua.append("\nc = redis.call('incr',KEYS[1])");
        lua.append("\nif tonumber(c) == 1 then");
        lua.append("\nredis.call('expire',KEYS[1],ARGV[2])");
        lua.append("\nend");
        lua.append("\nreturn c;");
        int limitCount = 10;
        int limitPeriod = 3;
        List<String> keys = new ArrayList<>();
        keys.add("kk");
        RedisScript<Number> redisScript = new DefaultRedisScript<>(lua.toString(), Number.class);
        Number count = stringRedisTemplate.execute(redisScript, keys, String.valueOf(limitCount), String.valueOf(limitPeriod));
        System.out.println(count);
    }

The debug code enters the execute method of the DefaultScriptExecutor class of spring-data-redis：

public <T> T execute(final RedisScript<T> script, final RedisSerializer<?> argsSerializer,
			final RedisSerializer<T> resultSerializer, final List<K> keys, final Object... args) {
		return template.execute((RedisCallback<T>) connection -> {
			final ReturnType returnType = ReturnType.fromJavaType(script.getResultType());
			final byte[][] keysAndArgs = keysAndArgs(argsSerializer, keys, args);
			final int keySize = keys != null ? keys.size() : 0;
			if (connection.isPipelined() || connection.isQueueing()) {
				// We could script load first and then do evalsha to ensure sha is present,
				// but this adds a sha1 to exec/closePipeline results. Instead, just eval
				connection.eval(scriptBytes(script), returnType, keySize, keysAndArgs);
				return null;
			}
			return eval(connection, script, returnType, keySize, keysAndArgs, resultSerializer);
		});
	}

In version 2.3.4, the ReturnType is Integer and IntegerOutPut will be generated, but in version 2.7.0, the ReturnType is VALUE and generates ValueOutPut, resulting in the above error, so I think ValueOutPut should support the processing of Number, which can solve this problem.

[tishun]

@Memorydoc , @ShepherdZFJ ,
Seems to me this is deffinetly an issue with spring-data-redis, perhaps sometihng like spring-projects/spring-data-redis#2908

This project works on the underlying driver and - unless the driver is the problem - there is nothing to be done in Lettuce.

Closing this, please reopen if you have some indications that the issue is in the Lettuce code.