[BUG] Seeing a string assigned to an object type.

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
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Description

I'm seeing the following error:

/Users/kevin.regan/src/kmsOpenAPIJavaClient/kmsOpenAPIBaseJavaClient/src/main/java/com/salesforce/sds/kms/client/kmsOpenAPIJavaClient/model/ExternalKeySpecDetails.java:61: error: incompatible types: String cannot be converted to EkmType
this.ekmType = this.getClass().getSimpleName();

The ExternalKeySpecDetails class:

@ApiModel(description = "Ekm Type")
@javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
public class ExternalKeySpecDetails {
public static final String SERIALIZED_NAME_EKM_TYPE = "ekmType";
@SerializedName(SERIALIZED_NAME_EKM_TYPE)
protected EkmType ekmType;

public ExternalKeySpecDetails() {
this.ekmType = this.getClass().getSimpleName();
}

public ExternalKeySpecDetails ekmType(EkmType ekmType) {
this.ekmType = ekmType;
return this;
}
...

The EkmType class:

@JsonAdapter(EkmType.Adapter.class)
public enum EkmType {

AWS_KMS("AWS_KMS");

private String value;

EkmType(String value) {
this.value = value;
}
...

openapi-generator version

6.2.1

OpenAPI declaration file content or url

ExternalKeySpecDetails:
  type: object
  properties:
    ekmType:
      $ref: '#/components/schemas/EkmType'
  description: Ekm Type
  discriminator:
    propertyName: ekmType
    mapping:
      AWS_KMS: '#/components/schemas/AwsKmsExternalKeySpec

EkmType:
  type: string
  description: "Ekm type [Beta, Not generally available]"
  enum:
  - AWS_KMS

Generation Details

Steps to reproduce

Related issues/PRs

Suggest a fix

Start by reproducing Java client generation from the supplied ExternalKeySpecDetails and EkmType OpenAPI schemas, then inspect the generated ExternalKeySpecDetails.java constructor and discriminator handling. Done means the generated Java client compiles without assigning the class name String to the EkmType field; add a focused regression test if the generator test location is identified.