Description

When trying to do a redis quide https://quarkus.io/guides/redis in kotlin I'm getting the following error java.lang.IllegalArgumentException: Unable to encode object of type class java.lang.Long when using ReactiveValueCommands with Long.

private val countCommands: ReactiveValueCommands<String, Long> = dataSource.value(Long::class.java)

The issue is that io.quarkus.redis.runtime.datasource.Marshaller constructor is receiving long as a class hint which then resolves to JsonCodec, but when Marshaller.codec(Class<?>) method is called in order to determine a codec, java.lang.Long is passed as a param. Ultimately the codec cannot be found because Marshaller.codecs map has a codec for long, not for java.lang.Long.

The solution is to do this:
private val countCommands: ReactiveValueCommands<String, Long> = dataSource.value(Long::class.javaObjectType)
instead of this:
private val countCommands: ReactiveValueCommands<String, Long> = dataSource.value(Long::class.java)

It would be easier to use this from kotlin without needing to explicitly specify javaObjectType.

The reproducer is here in qs-redis module - https://github.com/tjakopan/quarkus-examples-kotlin. In order to reproduce the error, one can comment out line 13 and un-comment line 14 in IncrementService class and run the tests.

Implementation ideas

io.quarkus.redis.datasource.codecs.Codecs class could specify a LongCodec, similar to already existing codecs for double, int, String and byte[]. And then the Codecs.getDefaultCodecFor(Class<T>) method could be changed to:

    public static <T> Codec<T> getDefaultCodecFor(Class<T> clazz) {
        if (clazz.equals(Double.class) || clazz.equals(Double.TYPE)) {
            return (Codec<T>) DoubleCodec.INSTANCE;
        }
        if (clazz.equals(Integer.class) || clazz.equals(Integer.TYPE)) {
            return (Codec<T>) IntegerCodec.INSTANCE;
        }
       if (clazz.equals(Long.class) || clazz.equals(Long.TYPE)) {
            return (Codec<T>) LongCodec.INSTANCE;
        }
        if (clazz.equals(String.class)) {
            return (Codec<T>) StringCodec.INSTANCE;
        }
        if (clazz.equals(byte[].class)) {
            return (Codec<T>) ByteArrayCodec.INSTANCE;
        }
        // JSON by default
        return new JsonCodec<>(clazz);
    }

Willing to contribute with this if needed.