Generic fields in ParameterObject are not resolved

[orange-buffalo]

Consider the following use-case, where @ParameterObject refers to a class that extends a parametrized class:

open class AbstractParameterObject<T : Enum<T>> {

    var primitiveBaseField: Int? = null
    var genericField: T? = null
}

enum class ConcreteEnum {
    ONE,
    TWO
}

class ConcreteParameterObject : AbstractParameterObject<ConcreteEnum>() {
    var primitiveConcreteField: Int? = null
}

@RestController
@RequestMapping("/")
class HelloController {

    @GetMapping
    fun test(@ParameterObject requestData: ConcreteParameterObject): String = "hello"

}

Expected schema should contain the genericField definition, but it does not:

"parameters": [
  {
    "name": "primitiveConcreteField",
    "in": "query",
    "required": false,
    "schema": {
      "type": "integer",
      "format": "int32"
    }
  },
  {
    "name": "primitiveBaseField",
    "in": "query",
    "required": false,
    "schema": {
      "type": "integer",
      "format": "int32"
    }
  }
],

I reproduced the problem with a test in springdoc-openapi code base - please see the branch changes - and was able to get the field in the API definition. Unfortunately, the schema is still not generated properly. The issue is that at the moment when calculateSchema is called, the information about the original parameter class (ConcreteParameterObject from the example above) is already lost and we only have the declaring class for the getter (AbstractParameterObject). Obviously, there is not enough information to resolve the type information and wrong schema gets generated (or not at all for the enum case).

[bnasslahsen]

@orange-buffalo,

Thank for your search and contribution.
I have added your proposed change.

There is an error related to swagger-core: swagger-api/swagger-core#3858
A NPE is thrown by Jackson, in the swagger-core call from ModelResolver._addEnumProps(ModelResolver.java:944)

But i think, your fix should be working for other cases, and you have workarounds for enum inheritance.

You can also test this enhancement using the latest snapshot.

Please have a look at this commit and tell if it covers your case ?

[orange-buffalo]

Hi @bnasslahsen, thank you for the solution. Yes, it covers the case. Hopefully once the Swagger issue is resolved, @Parameter(schema=@Schema(type = "string", allowableValues = {"ONE", "TWO"}) ) workaround can be removed and schema gets generated based on the types.