The decriminator is set only if the "mapping" field is present

[Antonboom]

Related to https://github.com/deepmap/oapi-codegen/pull/471

Hello!

mapping field is useful for explicit mapping:

In scenarios where the value of the discriminator field does not match the schema name or implicit mapping is not possible, an optional mapping definition MAY be used

But by default I expected the generated code to set the descriminator field by schema name:

The expectation now is that a property with name petType MUST be present in the response payload, and the value will correspond to the name of a schema defined in the OAS document.

MyResponseType:
  oneOf:
  - $ref: '#/components/schemas/Cat'
  - $ref: '#/components/schemas/Dog'
  - $ref: '#/components/schemas/Lizard'
  discriminator:
    propertyName: petType

But now it doesn't work like that. Thanks.

[Antonboom]

@jamietanna @deepmap-marcinr @Warboss-rus FYI