Serializer for class 'ArrayList' is not found.

[pwlan]

Describe the bug

Hi,
thanks for the fix of #23678

But it looks like this has introduced a new issue.
When using Lists, the following error ocurrs.

Serializer for class 'ArrayList' is not found.
Mark the class as @Serializable or provide the serializer explicitly.

The issue can be easily reproduced:

fun main() {
    val arrayList = ArrayList<String>()
    Json{}.encodeToString(serializer(arrayList.javaClass), arrayList) // this will fail.
}

or

    @Path("list")
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    fun listHello() = listOf(Person("Jim Halpert"))

In the case of a list, the Kotlin ListSerializer needs to be used. The same applies to Sets.

Quarkus Version

Quarkus 2.12.2

Expected behavior

It should produce beautiful json.

Originally posted by @pwlan in #23678 (comment)

[gsmet]

Can you provide a small reproducer?

[quarkus-bot]

/cc @evanchooly, @geoand

[geoand]

As Guillaume mentions, a reproducer is essential here.

[pwlan]

Thanks for the super fast response!

Interesting... we get it every time in our app... but are having trouble reproducing it with a fresh hello world... this might take a moment.

Otherwise, in the case of Lists, is https://github.com/quarkusio/quarkus/blob/main/extensions/resteasy-reactive/quarkus-resteasy-reactive-kotlin-serialization/runtime/src/main/kotlin/io/quarkus/kotlin/serialization/KotlinSerializationMessageBodyWriter.kt still used to serialize the data?

[geoand]

Yeah, that should be coming into play

[pwlan]

Ok, we are 1 step closer. It all comes down to the KotlinSerializationMessageBodyWriter.kt.

On the Reproducer App, KotlinSerializationMessageBodyWriter#writeRsponse is callled and that works.
On our App, KotlinSerializationMessageBodyWriter#writeTo is called and that failes.
The line is 29, json.encodeToStream(serializer(o.javaClass) , o, entityStream). If o is, for example, HashArray it will fail.

So 2 questions:

1. Any info on how to control what method is called?
2. Should KotlinSerializationMessageBodyWriter#writeTo work if o is an Array?

[geoand]

Would you be able to try out #28134 (see this for how to build the project)?

[geoand]

Seems like some of the tests are failing, so there is more I need to look into

[pwlan]

Ok, found the culprit.

When adding "io.quarkus:quarkus-smallrye-opentracing" as a dependency KotlinSerializationMessageBodyWriter#writeTo is called, whichs fails.

I can create a reproducer later....

[geoand]

@pwlan any change you have a reproducer? It would really help in narrowing down what is going on here.

[pwlan]

Of course
quarkus-issue.zip

Just run the tests.

Any other questions, just let me know.

[geoand]

Great, thanks!