[BUG] java-inflector templates do not generate proper hashCode and equals functions

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

JavaInflector/pojo.mustache does not generate proper hashCode and equals functions

openapi-generator version

latest

OpenAPI declaration file content or url

https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/test/resources/3_0/allOf.yaml

openapi: 3.0.1
info:
  version: 1.0.0
  title: Example
  license:
    name: MIT
servers:
  - url: http://api.example.xyz/v1
paths:
  /person/display/{personId}:
    get:
      parameters:
        - name: personId
          in: path
          required: true
          description: The id of the person to retrieve
          schema:
            type: string
      operationId: list
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Person"
components:
  schemas:
    Person:
      type: object
      discriminator:
        propertyName: $_type
        mapping:
          a: '#/components/schemas/Adult'
          c: Child
      properties:
        $_type:
          type: string
        lastName:
          type: string
        firstName:
          type: string
    Adult:
      description: A representation of an adult
      allOf:
      - $ref: '#/components/schemas/Person'
      - type: object
        properties:
          children:
            type: array
            items:
              $ref: "#/components/schemas/Child"
    Child:
      description: A representation of a child
      allOf:
      - type: object
        properties:
          age:
            type: integer
            format: int32
      - $ref: '#/components/schemas/Person'

Command line used for generation

docker run --rm -v /local/openapi:/local openapitools/openapi-generator-cli generate -o /local/out -i /local/allOf.yaml -g java-inflector

Steps to reproduce

in the Generated Classes you can see that the super class is not considered in equals or hash code

  @Override
  public boolean equals(java.lang.Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    Adult adult = (Adult) o;
    return Objects.equals(children, adult.children);
  }

  @Override
  public int hashCode() {
    return Objects.hash(children);
  }

After the patch below

  @Override
  public boolean equals(java.lang.Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    Adult adult = (Adult) o;
    return Objects.equals(this.children, adult.children) &&
      super.equals(o);
  }

  @Override
  public int hashCode() {
    return Objects.hash(children, super.hashCode());
  }

Related issues/PRs

Suggest a fix

diff --git a/modules/openapi-generator/src/main/resources/JavaInflector/pojo.mustache b/modules/openapi-generator/src/main/resources/JavaInflector/pojo.mustache
index badfdbc35a..f824eb3af9 100644
--- a/modules/openapi-generator/src/main/resources/JavaInflector/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaInflector/pojo.mustache
@@ -48,7 +48,6 @@ public class {{classname}} {{#parent}}extends {{{parent}}}{{/parent}} {{#seriali
   }
 
   {{/vars}}
-
   @Override
   public boolean equals(java.lang.Object o) {
     if (this == o) {
@@ -57,15 +56,17 @@ public class {{classname}} {{#parent}}extends {{{parent}}}{{/parent}} {{#seriali
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    {{classname}} {{classVarName}} = ({{classname}}) o;{{#hasVars}}
-    return {{#vars}}Objects.equals({{name}}, {{classVarName}}.{{name}}){{#hasMore}} &&
-        {{/hasMore}}{{^hasMore}};{{/hasMore}}{{/vars}}{{/hasVars}}{{^hasVars}}
+    {{#hasVars}}
+    {{classname}} {{classVarName}} = ({{classname}}) o;
+    return {{#vars}}Objects.equals(this.{{name}}, {{classVarName}}.{{name}}){{#hasMore}} &&
+      {{/hasMore}}{{/vars}}{{#parent}} &&
+      super.equals(o){{/parent}};{{/hasVars}}{{^hasVars}}
     return true;{{/hasVars}}
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash({{#vars}}{{name}}{{#hasMore}}, {{/hasMore}}{{/vars}});
+    return Objects.hash({{#vars}}{{name}}{{#hasMore}}, {{/hasMore}}{{/vars}}{{#parent}}{{#hasVars}}, {{/hasVars}}super.hashCode(){{/parent}});
   }
 
   @Override

Start with modules/openapi-generator/src/main/resources/JavaInflector/pojo.mustache and reproduce generation using the provided allOf.yaml and java-inflector Docker command. Update the generated equals and hashCode behavior for inherited models, then verify that generated subclasses include their superclass comparisons and hash values.