Eval lua script expects return integer but null

[CodePlayer]

Bug Report

Current Behavior

There is a string key named a, which value is 1 in Redis.
I want to read the value as Long by lua script.
However, it returns null unexpectedlly.

Input Code

// code example
final RedisCommands<String, String> redisCommands = redisClient.connect().sync();
redisCommands.set("a", "1"); // SET a 1

String luaScript = "return redis.call('GET', KEYS[1])";
Long val = redisCommands.eval(luaScript, ScriptOutputType.INTEGER, "a");
System.out.println(val); // expect output "1" but "null"

Expected behavior/code

return 1 as expected ( OR maybe throw exception ) . Does NOT return null silently.

Environment

• Lettuce version(s): 6.1.9.RELEASE
• Redis version: 6.0.14

Possible Solution

Enhance type conversion compatibility. Throw an exception when the types are still not compatible.

Additional context

BTW, Redisson client works well in same situation.

[mp911de]

Thanks for the report. It is indeed unfortunate that we silently fall back to null. The offending piece of code is quite old, so let's see what happens if we fix that.

[mp911de]

We now attempt best-effort parsing. In your example, the return value is a String ("1") and not an Integer. We no longer fall silently back to null.