jsonschema - JSON Schema - conditional validation

Question

I have the following Schema. I've implemented it as best I can, but it's still not working quite as I want it to.

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "type": "object",
    "title": "Ordering pizza",
    "propertyNames": {
        "enum": [
            "q-who-did-you-order-from",
            "q-did-they-accept-your-order",
            "q-how-much-was-the-bill",
            "q-why-didnt-they-accept"
        ]
    },
    "properties": {
        "q-who-did-you-order-from": {
            "type": "string",
            "title": "Who have you ordered pizza from?",
            "maxLength": 50,
            "errorMessages": {
                "required": "Enter who you ordered from",
                "maxLength":
                    "Who you ordered from must be 50 characters or less"
            }
        },
        "q-did-they-accept-your-order": {
            "title": "Have they accepted your order?",
            "type": "boolean",
            "errorMessages": {
                "required":
                    "Select yes if they have accepted your order"
            }
        },
        "q-how-much-was-the-bill": {
            "type": "string",
            "title": "How much was the bill?",
            "maxLength": 50,
            "errorMessages": {
                "required": "Enter an amount",
                "maxLength": "Amount must be 50 characters or less"
            }
        },
        "q-why-didnt-they-accept": {
            "type": "string",
            "title": "Why wasnt your order accepted?",
            "description":
                "If you do not know you can say so.",
            "maxLength": 50,
            "errorMessages": {
                "required": "Enter a reason",
                "maxLength": "Reason must be 50 characters or less"
            }
        }
    },
    "required": ["q-who-did-you-order-from", "q-did-they-accept-your-order"],
    "allOf": [
        {
            "$ref": "#/definitions/if-false-then-q-why-didnt-they-accept-is-required"
        },
        {
            "$ref": "#/definitions/if-true-then-q-how-much-was-the-bill-is-required"
        }
    ],
    "definitions": {
        "if-false-then-q-why-didnt-they-accept-is-required": {
            "if": {
                "properties": {
                    "q-did-they-accept-your-order": {
                        "const": false
                    }
                }
            },
            "then": {
                "required": ["q-why-didnt-they-accept"],
                "propertyNames": {
                    "enum": [
                        "q-who-did-you-order-from",
                        "q-did-they-accept-your-order",
                        "q-why-didnt-they-accept"
                    ]
                }
            }
        },
        "if-true-then-q-how-much-was-the-bill-is-required": {
            "if": {
                "properties": {
                    "q-did-they-accept-your-order": {
                        "const": true
                    }
                }
            },
            "then": {
                "required": ["q-how-much-was-the-bill"],
                "propertyNames": {
                    "enum": [
                        "q-who-did-you-order-from",
                        "q-did-they-accept-your-order",
                        "q-how-much-was-the-bill"
                    ]
                }
            }
        }
    }
}

The expectation is that the user will enter a value for q-who-did-you-order-from and q-did-they-accept-your-order, then only one of the remaining two questions based on their answer for q-did-they-accept-your-order.

So the following inputs should validate:

{
    "q-did-you-order-from": "Pizza hut",
    "q-did-they-accept-your-order": "true",
    "q-how-much-was-the-bill": "20"
}



{
    "q-did-you-order-from": "Pizza hut",
    "q-did-they-accept-your-order": "false",
    "q-why-didn't-they-accept": "Incorrect card details"
}

Similarly, I would expect the following inputs to fail validation and throw a 'required' error for the field containing a blank string. The first should throw an error because q-why-didn't-they-accept is empty:

{
    "q-did-you-order-from": "Pizza hut",
    "q-did-they-accept-your-order": "false",
    "q-why-didn't-they-accept": ""
}

And this one should throw an error because q-how-much-was-the-bill is empty.

{
    "q-did-you-order-from": "Pizza hut",
    "q-did-they-accept-your-order": "true",
    "q-how-much-was-the-bill": ""
}

And it does! This works as expected. However, we found a bug that arises from the user not entering an answer to q-did-they-accept-your-order. The answers to these questions are POSTed via the browser on form submission. In the browser, the boolean question is presented as yes/no radio buttons. As a result, when the user does not check either radio, but does try to submit the form, the answer for the radios is omitted entirely. The data object sent looks like this:

{
    "q-did-you-order-from": "Pizza hut",
    "q-how-much-was-the-bill": "",
    "q-why-didn't-they-accept": "",
}

My EXPECTED result here:

AJV throws only one 'required' error for q-did-they-accept-your-order. It shouldn't throw a 'required' error for anything else as both q-how-much-was-the-bill and q-why-didn't-they-accept aren't required unless the related value for q-did-they-accept-your-order is selected.

My ACTUAL result:

AJV Throws an error for all three empty inputs.

So my question is, how do I get AJV to validate this schema and for ONLY q-did-they-accept-your-order to throw a required error when the question is not answered.

EDIT:

The output from AJV is as follows:

[
    {
        "keyword": "required",
        "dataPath": "",
        "schemaPath": "#/required",
        "params": {
            "missingProperty": "q-did-they-accept-your-order"
        },
        "message": "should have required property 'q-did-they-accept-your-order'"
    },
    {
        "keyword": "required",
        "dataPath": "",
        "schemaPath": "#/definitions/if-false-then-q-why-didnt-they-accept-is-required",
        "params": {
            "missingProperty": "q-why-didnt-they-accept"
        },
        "message": "should have required property 'q-why-didnt-they-accept'"
    },
    {
        "keyword": "if",
        "dataPath": "",
        "schemaPath": "#/definitions/if-false-then-q-why-didnt-they-accept-is-required/if",
        "params": {
            "failingKeyword": "then"
        },
        "message": "should match "then" schema"
    },
    {
        "keyword": "required",
        "dataPath": "",
        "schemaPath": "#/definitions/if-true-then-q-how-much-was-the-bill-is-required/then/required",
        "params": {
            "missingProperty": "q-how-much-was-the-bill"
        },
        "message": "should have required property 'q-how-much-was-the-bill'"
    },
    {
        "keyword": "if",
        "dataPath": "",
        "schemaPath": "#/definitions/if-true-then-q-how-much-was-the-bill-is-required/if",
        "params": {
            "failingKeyword": "then"
        },
        "message": "should match "then" schema"
    }
]

Answer 1

There's a part missing from your application of the if/then pattern. Let's use this simple schema as an example.

{
  "if": {
    "properties": {
      "foo": { "const": true }
    }
  },
  "then": {
    "required": ["bar"]
  }
}

If I validate {} against this schema, it will fail saying that the property "bar" is required. Because the /if schema doesn't require the "foo" property, {} is valid and therefore the /then schema applies. To fix this problem, you just need to make the "foo" property required.

{
  "if": {
    "properties": {
      "foo": { "const": true }
    },
    "required": ["foo"]
  },
  "then": {
    "required": ["bar"]
  }
}

Now, {} is valid against the schema. the /then schema will only apply if there is a "foo" property and it's value is true.