[ANDROID] Codegen - extended model contains duplicated properties from base model

Description

 com.android.volley.VolleyError: io.swagger.client.ApiException: class io.swagger.client.model.MyRequest declares multiple JSON fields named XXCustom01

If you have two definitions, where the second one extends the first one, the fields from the first definition are also declared in the model of the second definition. This will throw the above error message.

Also the properties of the first model should be declared protected instead of private.

Swagger-codegen version

Swagger Editor
Version 2.10.3

Swagger declaration file content or url

swagger: '2.0'
info:
  version: 1.0.0
  title: Test
  description: ''
schemes: []
consumes: []
produces: []
tags:
  - name: CommonService
    description: ''
definitions:
  AbstractEntity:
    type: object
    title: AbstractEntity
    properties:
      XXCustom01:
        description: ''
        type: string
      XXCustom02:
        description: ''
        type: string
    description: Base entity
  MyRequest :
    type: object
    title: MyRequest 
    allOf:
      - $ref: '#/definitions/AbstractEntity'
      - properties:
          Property01:
            description: A special property.
            type: string
    description: ''

Command line used for generation

editor.swgger.io

Generated models

first model

@ApiModel(description = "Base entity")
public class AbstractEntity {
  
  @SerializedName("XXCustom01")
  private String xXCustom01 = null;
  @SerializedName("XXCustom02")
  private String xXCustom02 = null;

  //...
}

second model

@ApiModel(description = "")
public class MyRequest extends AbstractEntity {
  
  @SerializedName("XXCustom01")
  private String xXCustom01 = null;
  @SerializedName("XXCustom02")
  private String xXCustom02 = null;
  @SerializedName("Property01")
  private String property01= null;

  //...
}

Suggest a Fix

Fields defined in the first model should not be defined in the second model that extends the first one.
Declare the properties of the models protected instead of private.

Start by reproducing the Swagger 2.0 example with the Android generator and compare the generated AbstractEntity and MyRequest models. Trace the model-generation handling for allOf inheritance; done means inherited properties are not redeclared in MyRequest and base-model properties have protected visibility.