Discriminator validation does not follow $ref resulting in false positives

[Andrew Thompson]

The code from swagger-request-validator / swagger-request-validator-core / src / main / java / com / atlassian / oai / validator / schema / SwaggerV20Library.java tries to validate discriminator fields have type=string.

 final JsonNode property = properties.get(discriminatorFieldName);
            if (!property.has("type") ||
                    !property.get("type").textValue().equalsIgnoreCase("string")) {
                report.error(msg(tree, bundle, "err.swaggerv2.discriminator.wrongType")
                        .putArgument("fieldName", discriminatorFieldName)
                );
                return;
            }

However, if the schema looks like this, where the discriminator is actually a $ref to a field defined elsewhere, it doesn't work because the code doesn't dereference the $ref first.

“Animal”: {
            "discriminator": “animalType",
            "type": "object",
            "required": [
                "animalType",
            ],
            "properties": {
…
                "animalType": {
                    "$ref": "/model/DataDictionary.json#/animalType"
                }
            }
        }
}

Conceptually it's an easy fix, just add 2 lines like this before doing the check.

while ( property is a $ref node )
    property = property. dereference

Is there a utility function in your library somewhere for doing this?

[James Navin]

Thanks for raising this.

I think this is the same, or related, to Issue #44.

The JSON schema validation in SRV is using the com.github.java-json-tools:json-schema-validator library. Taking a quick look there appears to be methods on the SchemaTree interface for resolving refs that might work in this scenario, but Id have to spend some time playing with it.