Synchronous dispatch of MULTI returns null

[tzxyz]

Bug Report

Current Behavior

public class LettuceTest {

    private final RedisClient client = RedisClient.create("redis://localhost");

    private final StatefulRedisConnection<String, String> connection = client.connect();

    @Test
    public void test() {
        String result = connection.sync().dispatch(CommandType.MULTI, new StatusOutput<String, String>(StringCodec.ASCII));
        Assert.assertSame("OK", result);	// expected return "OK" but null
    }
}

Stack trace

// your stack trace here;

Input Code

Input Code

        String result = connection.sync().multi();    // return "OK" 
        String customCommandResult = connection.sync().dispatch(CommandType.MULTI, new StatusOutput<String, String>(StringCodec.ASCII));    // return null

Expected behavior/code

Environment

• Lettuce version(s): [e.g. 5.2.1.RELEASE]
• Redis version: [e.g. 4.0.10]

Possible Solution

in io.lettuce.core.FutureSyncInvocationHandler#isTransactionActive it shoule be

    private static boolean isNonTxControlMethod(String methodName, Object[] args) {
        return !methodName.equals("exec")
                && !methodName.equals("multi")
                && !methodName.equals("discard")
                && !(methodName.equals("dispatch") && args.length > 0 && args[0] == CommandType.MULTI)
                && !(methodName.equals("dispatch") && args.length > 0 && args[0] == CommandType.EXEC)
                && !(methodName.equals("dispatch") && args.length > 0 && args[0] == CommandType.DISCARD);
    }

Additional context

[mp911de]

Thanks for raising the issue. It makes sense to return responses as we do the same for the regular API.

[mp911de]

Fixed via #1336.