Use case: list of abtract elements

[graham2071]

Hello,

I am new to json-schema, and try to create a schema which expresses the following constraint: "a list of various elements".
As an example, let's take a json containing a list of "Animals". An animal can be a "Dog", a "Wolf" or a "Turtle". They share some common properties ("name"), and have specific ones.

Example:

{
    "listOfAnimals": 
    [
        {
            "type": "dog",
            "name": "Doggy",
            "owner": "bob"
        },
        {
            "type": "wolf",
            "name": "wolfy",
            "pack": 0
        }
    ]
}

The problem of my first schema implementation is that Ajv validator returns a lot of errors (for what I consider a single error in the data), because it explores all branches.
Here is an excerpt from the schema (full is here: https://gitlab.com/graham2071/json-schema-example/blob/master/test/case1/animals.schema.json):

"animal": {
            "$id": "#Animal",
            "type": "object",
            "anyOf": [
                {
                    "$ref": "#Dog"
                },
                {
                    "$ref": "#Wolf"
                },
                {
                    "$ref": "#Turtle"
                }
            ]
        },

So I've come to try different implementations, and am wondering if I missed something.
My conclusion is to use "if" to force the selection of the correct branch in Ajv.

You can see all my tests here: https://gitlab.com/graham2071/json-schema-example
Running npm test will print out the number of errors found by Ajv.

Thanks for your help,
g.

[handrews]

@graham2071 work on error reporting and output is being tracked in #643, so I am closing this in favor of that one, which you should follow. The case you are mentioning (verbose errors because of anyOf or similar keywords) is one of the primary cases they are discussing there, so there is no need to re-state it. Note that #643 is the summary of older discussions, so don't worry if you don't see your use case listed out directly. It's one of the major motivations.

[handrews]

Note that any specific issues with Ajv should be filed at that repository- this repository is only for the specification, not implementations.

[graham2071]

@handrews thank you very much for your answer. I'll stick to the anyOf and oneOf(without if) and filter the validation errors for now.