Describe the bug

required fields declared in an allof are missing in the generated python code.

If this is not a bug, please let me know if I'm doing something wrong.

To Reproduce

Example schema:

    ProjectedPet:
      type: object
      properties:
        id:
          type: integer
          format: int64
        name:
          type: string
    Pet:
      allOf:
        - $ref: "#/components/schemas/ProjectedPet"
        - type: object
          required:
            - id
            - name
            - opts
          properties:
            tag:
              type: string
            opts:
              type: array
              items:
                type: string

Used commandline:

datamodel-codegen --input api.yaml --output model.py --input-file-type openapi --use-annotated --collapse-root-models  --use-standard-collections --capitalize-enum-members  --target-python-version 3.10 --output-model-type pydantic_v2.BaseModel

Actual behavior

class ProjectedPet(BaseModel):
    id: Optional[int] = None
    name: Optional[str] = None

class Pet(ProjectedPet):
    tag: Optional[str] = None
    opts: list[str]

Expected behavior

class ProjectedPet(BaseModel):
    id: Optional[int] = None
    name: Optional[str] = None

class Pet(ProjectedPet):
    id: int
    name: str
    tag: Optional[str] = None
    opts: list[str]

Version:

• OS: MacOS 14.6.1
• Python version: 3.11
• datamodel-code-generator version: 0.25.9