Regression on 4.0.0-RC1: spring-boot-starter-kotlin-serialization

[bcmedeiros]

I've been using Spring Boot 4 since the M2 and I have a simple web application with spring-boot-starter-web and springdoc-openapi-starter-webmvc-api.

My own endpoints use kotlinx-serialization, but SpringDoc continue to rely on jackson for their API.

In the M3 release I had some issues with my SpringDoc endpoint, my api-docs endpoint was producing a array of integers instead of the actual payload (due to it being serialized as byte array, I'd assume). I had a quick look and figured I had to add spring-boot-starter-kotlin-serialization so I could have proper kotlinx-serialization support, and that fixed the problem. Serialization would prefer kotlinx to the annotated objects, fallback to something else if not.

Just upgraded to RC1 now, and we are back to SpringDoc producing a list of bytes in the output, but this time spring-boot-starter-kotlin-serialization is present. Maybe there's some further configuration we need to do on M4 now, but I couldn't find it, so I'm reporting this as a bug.

Let me know if you need more details.

[wilkinsona]

Thanks for trying the RC. We will need some more details, please. Can you please provide a minimal sample that behaves as you have described when upgraded from M3 to RC1? You can share it with us by pushing it to a separate repository on GitHub or by zipping it up and attaching it to this issue.