I looked a bit into the code, here is what I found could work with kotlinx.serialization: https://github.com/Yelp/swagger-gradle-codegen/pull/136 I understand that this work is not finished before the polymorphism logic is ready.

Do you have an error message to share?

I thought that locally klint passed but then the ci complained

Can you run

./gradlew preMerge

?

no, just runHooks

Yeah run hooks will run the pre-commit hooks but only on your index.