[BUG][JAVA] incline+oneOf schema create field type onto itself

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?

Description

When declaring a oneOf field with inline schema; the inline generated type is based onto title
If a schema with this name is already existing/defined it is ignored and then finally it produce the final class coming from the oneOf declaration to reference itself

The following warning is present: Inline schema created as Field_Type_1. To have complete control of the model name, set the title field or use the modelNameMapping option (e.g. --model-name-mappings Field_Type_1=NewModel,ModelA=NewModelA in CLI) or inlineSchemaNameMapping option (--inline-schema-name-mappings Field_Type_1=NewModel,ModelA=NewModelA in CLI).

So seems to an expected behavior but it conduct onto the current issue.

openapi-generator version

Tested with 7.3.0 and current master

OpenAPI declaration file content

This is a curated sample: the allOf and oneOf are more complex but required with full OAS content

openapi: 3.0.3
info:
  description: POC about oneOf auto generated schema issue
  title: oneOf POC
  version: "1.0"
  license:
    name: MIT
    url: "https://foo.org"
  contact:
    email: support@foo.org
    name: support at foo dot org
paths:
  '/foo':
    get:
      tags:
        - foo
      summary: Get a foo
      description: foo
      operationId: foo_GetFoo
      responses:
        "200":
          $ref: "#/components/responses/getFooResponse"
tags:
  - description: foo
    name: foo
components:
  responses:
    getFooResponse:
      description: A successful response.
      content:
        application/json:
          schema:
            $ref: "#/components/schemas/FooResponse"
  schemas:
    FooResponse:
      description: foo
      type: object
      title: Foo API
      properties:
        response_field:
          description: an array of fields
          type: array
          items:
            $ref: "#/components/schemas/ResponseField"
    ResponseField:
      type: object
      description: foo
      allOf:
        - $ref: "#/components/schemas/FieldTypes"
    FieldTypes:
      type: object
      oneOf:
        - type: object
          title: Field Type 1
          properties:
            my_field:
              $ref: "#/components/schemas/FieldType1"
    FieldType1:
      description: Field Type 1 description
      type: object
      title: Field Type 1
      properties:
        property1:
          description: property 1 for field type 1
          type: string

Command line used for generation

java -cp modules/openapi-generator-cli/target/openapi-generator-cli.jar org.openapitools.codegen.OpenAPIGenerator generate -g java -i oneOfField-poc.yaml -o /tmp/openapi-generator/generated

Steps to reproduce

Execute the above command

Related issues/PRs

Generate file

The generated FieldType1 class is declaring myField variable of type FieldType1 (so it own class)

public class FieldType1 {
...
  private FieldType1 myField;
...
}

FieldType1 class should contains the explicitly defined schema (the last schema from sample above) with the property1 field of type string

Start by running the Java generator command against the provided oneOfField-poc.yaml sample and inspect the generated FieldType1 class. Trace how the inline oneOf schema and the existing FieldType1 schema are named and resolved. Done means the generated myField no longer references FieldType1 itself and the class contains property1 as a string.