Swagger upload causing exception: Too many keys in Spyc.php

[fishbd1]

We are getting an uncaught exception from Spyc.php when attempting to upload a swagger. It's causing WSOD. I believe that this is due to the resource using polymorphic behavior. Is there a way around this error?

Exception: Too many keys: description: "Field indicating which smart program the policy type is. Values map to current Mainframe as follows: in Spyc->checkKeysInValue() (line 1061 of /srv/bindings/cc051908336b4db784b5a4c73134d96c/code/profiles/apigee/libraries/spyc/Spyc.php).

Swagger:

 DeviceProgramChangeToVehicle:
    allOf:
      - $ref: '#/definitions/ChangeToVehicle'
      - type: object
        description: Payload to create new vehicle enrollment record.
        properties:
          device:
            $ref: '#/definitions/DeviceChangeToVehicle'
          vehicle:
            $ref: '#/definitions/VehicleChangeToVehicle'

polymorphism.png