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

This appears to be a regression from handling 3.0 specs. If I switch the openapi version from 3.1.0 to 3.0.0 then the correct output is produced.

When a field is of type

anyOf:
  - type: string
  - type: array
    items:
      type: string

The generated code ignores the array and produces

    field: Optional[StrictStr] = Field(...)

It does the right thing when it's

anyOf:
  - type: string
  - type: number

Producing

    field: Field = Field(...)

openapi-generator version

latest/7.2.0

docker pull openapitools/openapi-generator-cli:latest
latest: Pulling from openapitools/openapi-generator-cli
Digest: sha256:7bfcb402ec4fef3af86c5ff38cec26c772db138120f931755da4a63a3cec5189

OpenAPI declaration file content or url

openapi: 3.1.0
paths: {}
info:
  version: 1.0.0
  title: Swagger Petstore
components:
  schemas:
    Cat:
      type: object
      title: Cat
      description: a cat
      required: [field]
      properties:
        field:
          title: field
          anyOf:
          - type: string
          - items:
              type: string

Generation Details

$ pip install openapi-spec-validator
$ openapi-spec-validator openapi.yaml
openapi.yaml: OK

$ docker run --rm -v ${PWD}:/local openapitools/openapi-generator-cli:latest generate -g python --additional-properties=generateSourceCodeOnly=true,packageName=client -o /local/ -i /local/openapi.yaml 

Output has no warnings/errors.

Steps to reproduce

1. Create openapi.yaml and generate code
2. Look in client/model/cat.py and observe list[str] is missing in the type of field
3. Switch to 3.0.0 in yaml
4. Regenerate code and observe the field now points to a new type which correctly expresses the union type

Related issues/PRs

None that I could find.

Suggest a fix

It seems like the array handling logic is incorrect.