PHP Client doesn't seem to support anyOf with discriminator

Description

I have the below spec and the generated php client doesn't seem to handle the combination of anyOf and discriminator. I see a property DISCRIMINATOR in the generated models but they're all null.

Swagger-codegen version

3.0.18, not sure if it's a regression

Swagger declaration file content or url

openapi: 3.0.0
info:
  title: Foo
  version: '1.0'
paths:
  /api/v1/object:
    get:
      operationId: get-object
      responses:
        '200':
          description: example
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ExampleResponse'
components:
  schemas:
    ObjectFoo:
      type: object
      required:
        - value
        - type
      properties:
        value:
          type: integer
        type:
          type: string
    ObjectBar:
      type: object
      required:
        - type
      properties:
        value:
          type: boolean
        type:
          type: string
    ExampleResponse:
      properties:
        objects:
          type: array
          items:
            anyOf:
              - $ref: '#/components/schemas/ObjectFoo'
              - $ref: '#/components/schemas/ObjectBar'
            discriminator:
              propertyName: type

Command line used for generation

I used brew to install codegen, command below:

swagger-codegen generate -i ./swagger-smol.yml -l php --config ./swagger-codegen/php-config.json -o ~/workspace/foo-client --git-user-id=foo --git-repo-id=foo

Steps to reproduce

Populate swagger-smol.yml with the above snippet and run the command above.

Related issues/PRs

I didn't find anything exactly like this but there are similar issues:

https://github.com/swagger-api/swagger-codegen/issues/4622
https://github.com/swagger-api/swagger-codegen/pull/3475
https://github.com/swagger-api/swagger-codegen/issues/4226
https://github.com/swagger-api/swagger-codegen/issues/4346
https://github.com/swagger-api/swagger-codegen/issues/3904

Suggest a fix/enhancement

Not sure...

Start by running the command against swagger-smol.yml with php-config.json and inspect the generated PHP models, especially their DISCRIMINATOR properties and handling of the ExampleResponse objects. Compare the generated result with the anyOf and discriminator declarations; done means the PHP client correctly distinguishes ObjectFoo and ObjectBar during response handling.