Support discriminator for polymorphic types and support oneOf

[bowenwr]

Is your feature request related to a problem? Please describe.

When an endpoint returns oneOf several different classes, currently it returns an empty object. Sample component snippet:

    ReturnedObject:
      oneOf:
        - $ref: '#/components/schemas/PolymorphicType'
        - $ref: '#/components/schemas/AnotherPolymorphicType'

Describe the solution you'd like

Support discriminators to be able to deserialize polymorphic types.

[dbanty]

I tested this with the latest code on main (roughly 0.7.0-rc.1) and it does attempt to generate proper responses now using the same code it would for unions inside a model (basically a series of try/except). So it's better than nothing, though for sure we still should add discriminators in a future version.

[oxfn]

Any updates on this? Is it possible to add support for discriminators with mapping like this?

"discriminator": {
  "propertyName": "type",
  "mapping": {
    "Product": "#/components/schemas/ProductOrderItem",
    "Compound": "#/components/schemas/CompoundOrderItem"
  }
}

Could you please advice any workaround to generate referenced models?

[oxfn]

Sorry for unneccessary bumping, didn't see #892

Anyway, question about quick & dirty workaround is actual :)