OpenAPI Extension Fails to Generate Schema for Generic Type that Uses Jackson JsonUnwrapped

Describe the bug

The Quarkus OpenAPI extension generates incorrect schema for generic Java types that use the Jackson JsonUnwrapped annotation.

smallrye-open-api recognizes Jackson's JsonUnwrapped annotation when generating schema objects (see https://github.com/smallrye/smallrye-open-api/pull/677/files).

Yet, something goes wrong when the annotated property is a parameterized type.

Expected behavior

The JsonUnwrapped annotation is on the property entity of type T. The resource method sets this type parameter to Greeting<LanguageAlternatives>>

record TimestampedEntity<T>(@JsonUnwrapped T entity, Instant timestamp) {}

record Greeting<T extends Alternative>(String message, T alternatives) {}

interface Alternative {}

record LanguageAlternatives(
    @Schema(required = true, example = "Hola") String spanish,
    @Schema(required = true, example = "Hallo") String german)
    implements Alternative {}

  /** In this case, the {@link TimestampedEntity#entity()} property is not unwrapped as expected. */
  @GET
  @Path("/unwrapped-not-handled")
  @Produces(MediaType.APPLICATION_JSON)
  public TimestampedEntity<Greeting<LanguageAlternatives>> greeting() {
    return new TimestampedEntity<>(
        new Greeting<>("hello", new LanguageAlternatives("Hola", "Hallo")), Instant.now());
  }

Expected the schema of the response from this endpoint to look like:

    TimestampedEntityGreetingLanguageAlternatives:
      type: object
      properties:
        alternatives:
          $ref: "#/components/schemas/Alternative"
        message:
          type: string
        timestamp:
          $ref: "#/components/schemas/Instant"

Actual behavior

Because, the extension does not respect the JsonUnwrapped annotation, so the message and alternatives are nested in the entity property that shouldn't exist.

    TimestampedEntityGreetingLanguageAlternatives:
      type: object
      properties:
        entity:
          $ref: "#/components/schemas/GreetingLanguageAlternatives"
        timestamp:
          $ref: "#/components/schemas/Instant"

Note there is another case in the GreetingResource class that causes the schema generation to fail in a slightly different way.

How to Reproduce?

The attached project builds the attached OpenAPI document. The comments in GreetingResource describe the use cases that do not work as expected.

quarkus-openapi-generics.openapi.yml.zip quarkus-openapi-generics.zip

Output of `uname -a` or `ver`

Darwin pixee-mbp-gilday.localdomain 24.0.0 Darwin Kernel Version 24.0.0: Tue Sep 24 23:39:07 PDT 2024; root:xnu-11215.1.12~1/RELEASE_ARM64_T6000 arm64

Output of `java -version`

openjdk version "21.0.3" 2024-04-16 LTS OpenJDK Runtime Environment Temurin-21.0.3+9 (build 21.0.3+9-LTS) OpenJDK 64-Bit Server VM Temurin-21.0.3+9 (build 21.0.3+9-LTS, mixed mode)

Quarkus version or git rev

3.16.4

Build tool (ie. output of `mvnw --version` or `gradlew --version`)

Apache Maven 3.9.9 (8e8579a9e76f7d015ee5ec7bfcdc97d260186937) Maven home: /Users/jgilday/.m2/wrapper/dists/apache-maven-3.9.9-bin/33b4b2b4/apache-maven-3.9.9 Java version: 21.0.3, vendor: Eclipse Adoptium, runtime: /Library/Java/JavaVirtualMachines/temurin-21.jdk/Contents/Home Default locale: en_US, platform encoding: UTF-8 OS name: "mac os x", version: "15.0.1", arch: "aarch64", family: "mac"

Additional information

No response

quarkusio / quarkus