Is readOnly flag misused in the schema?

[alexbudarov]

In the openapi.yml, for the PetType definition, "id" property is marked as readOnly:

    PetType:
      title: Pet type
      description: A pet type.
      allOf:
        - $ref: '#/components/schemas/PetTypeFields'
        - type: object
          properties:
            id:
              title: ID
...
              readOnly: true
          required:
            - id

According to the OpenAPI specification, this means:

Declares the property as "read only". This means that it MAY be sent as part of a response but SHOULD NOT be sent as part of the request.

see https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.2.md#fixed-fields-20

This means: when I call "addPet" operation to create a new Pet, by specification I shouldn't be able to specify Pet -> type -> id field. Though it is this particular field which is responsible for handling association.

Example of a problem that may occur - is the OpenAPI client generator.
See this change: OpenAPITools/openapi-generator#1582
If using this code generator, the generated PetType pojo will not have a PetType#setId() attribute.

Summary:
I think that readOnly flag is misused in this schema, and it shouldn't be used, for objects that are used as request parameters.

[alexbudarov]

similar problem is described here: #103 (comment)

[arey]

I don't know if the readOnly flag is misused or not, but when we call the POST /api/owners/{ownerId}/pets endpoint without giving pet id and name we have an error 400. Thus there is an issue that we have to fix.

[arey]

See #125