[BUG] [SPRING] OpenAPI Generator generates enums with that does not implement the interface for model with "OneOf" in the schema

[jimisola]

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?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

openapi-generator version

7.1.0

OpenAPI declaration file content or url

      "DefaultPublicationType": {
        "type": "string",
        "enum": [
          "FLIGHT_DATA",
          "ARRIVAL_SEQUENCE_DATA",
          "AIRPORT_CONFIGURATION_DATA"
        ]
      },
      "OtherPublicationType": {
        "type": "string",
        "pattern": "^OTHER:[A-Z_][A-Z0-9_]*$"
      },
      "Publication": {
        "description": "A SWIM Publication identifies a topic together with its content type, formal content type definition, and supported filters.",
        "oneOf": [
          {
            "$ref": "#/components/schemas/DefaultPublicationType"
          },
          {
            "$ref": "#/components/schemas/OtherPublicationType"
          }
        ]
      },

Generation Details

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen")
public interface Publication {
}

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen")
public enum DefaultPublicationType {
  
  FLIGHT_DATA("FLIGHT_DATA"),
  
  ARRIVAL_SEQUENCE_DATA("ARRIVAL_SEQUENCE_DATA"),
  
  AIRPORT_CONFIGURATION_DATA("AIRPORT_CONFIGURATION_DATA");

  private String value;

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

  @JsonValue
  public String getValue() {
    return value;
  }

  @Override
  public String toString() {
    return String.valueOf(value);
  }

  @JsonCreator
  public static DefaultPublicationType fromValue(String value) {
    for (DefaultPublicationType b : DefaultPublicationType.values()) {
      if (b.value.equals(value)) {
        return b;
      }
    }
    throw new IllegalArgumentException("Unexpected value '" + value + "'");
  }
}

Steps to reproduce

 <configuration>
                            <!-- see: https://openapi-generator.tech/docs/generators/spring/-->
                            <skipValidateSpec>true</skipValidateSpec>
                            <inputSpec>${project.basedir}/src/main/resources/openapi.json</inputSpec>
                            <generatorName>spring</generatorName>
                            <configOptions>
                                <useSpringBoot3>true</useSpringBoot3>
                                <useOneOfInterfaces>true</useOneOfInterfaces>
                                <useOptional>true</useOptional>
                                <annotationLibrary>swagger2</annotationLibrary>
                                <delegatePattern>true</delegatePattern>
                                <hideGenerationTimestamp>true</hideGenerationTimestamp>
                                <hateoas>true</hateoas>
                                <useBeanValidation>true</useBeanValidation>
                                <performBeanValidation>true</performBeanValidation>
                            </configOptions>
                        </configuration>

Related issues/PRs

#16672 #14807 #11715 #15

Suggest a fix

The generated enumeration should implement the interface.