Validating Polymorphic model types

[amarzavery]

Problem

Polymorphic models are not being validated correctly. For example Cat and Dog are having an allOf relationship with Animal which has a discriminator property named dtype, then at runtime the request body or the response body could be an Animal or a Cat or a Dog. If the model specified was a Cat then sway would not fail if some required properties of Cat were not provided.

A possible solution

I added"additionalProperties": false on all the models that do not have any additionalProperties set. This makes their json schema stricter. Now if any unknown property is given the validator will fail. On top of that I have changed all the references to polymorphic models to be a oneOf the parent model or it's children. That is wherever Animal is being referenced "$ref": "#/definitions/Animal", I updated that reference to be a oneOf reference

"oneOf": [ 
    {"$ref": "#/definitions/Animal"}, 
    {"$ref": "#/definitions/Cat"}, 
    {"$ref": "#/definitions/Dog"}
]

Thus when the modified swagger is given to z-schema validator (package on which sway depends for model validation), it does a crisp job of validating polymorphic model types.

• It would be nice to have a config that in sway that customers can set to make model validation stricter.

[whitlockjc]

Duplicate of #28.