Json schema oneOf with additionalProperties draft-04 - json

Question

I am trying to make a schema for validating a policy language. Short:
a policy is associated with an assertion. This assertion can either be an operator (and, or, not) and contains a list of other assertions. An assertion can also be a primitive (leaf node).
I made an UML design to make things easier to understand:
UML diagram
{
"policy": {
"name": "test",
"expression": {
"operator": "all",
"value": [
{
"primitive": "encrypt",
"preference": 12345,
"usage": "required"
},
{
"primitive": "sign",
"preference": 12345,
"usage": "required"
}
],
"preference": 12345,
"usage": "required"
}
}
}
And here is the scheme I currenty made:
{
"$schema": "http://json-schema.org/draft-04/schema#",
"type": "object",
"minProperties": 1,
"additionalProperties": {
"$ref": "#/definitions/policy"
},
"definitions": {
"policy": {
"title": "Policy",
"type": "object",
"required": [
"name",
"expression"
],
"additionalProperties": false,
"properties": {
"name": {
"type": "string"
},
"expression": {
"$ref": "#/definitions/assertion"
}
}
},
"operator": {
"properties": {
"value": {
"type": "array",
"items": {
"$ref": "#/definitions/assertion"
}
},
"operator": {
"enum": [
"allOne",
"all"
]
}
}
},
"primitive": {
"properties": {
"primitive": {
"enum": [
"encrypt",
"sign"
]
}
}
},
"assertion": {
"type": "object",
"additionalProperties": false,
"oneOf": [
{
"$ref": "#/definitions/operator"
},
{
"$ref": "#/definitions/primitive"
}
],
"properties": {
"preference": {
"type": "integer",
"minimum": 0,
"exclusiveMinimum": true
},
"usage": {
"enum": [
"required",
"rejected",
"optional",
"observed",
"ignored"
]
}
}
}
}
}
With the use of "oneOf" I'm trying to either use the specification of an operator or a primitive. But I'm not sure this is the way to go because i received the following error:
"message" : "object instance has properties which are not allowed by the schema: [\"operator\",\"value\"]"
The error message complains about extra properties which are not defined (because of "additionalProperties": false). However, these are defined in the definitions...

Answer 1

The oneOf, anyOf, ... keywords cannot be used for referencing other definitions. They do work for required. The solution is to declare all properties and only require the properties that are needed in the context. My example would become the following:
"assertion": {
"type": "object",
"additionalProperties": false,
"oneOf": [
{
"required": [
"operator"
]
},
{
"required": [
"primitive"
]
}
],
"properties": {
"operator": {
"$ref": "#/definitions/operator"
},
"primitive": {
"$ref": "#/definitions/primitive"
},
"preference": {
"type": "integer",
"minimum": 0,
"exclusiveMinimum": true
},
"usage": {
"enum": [
"required",
"rejected",
"optional",
"observed",
"ignored"
]
}
}
}