additionalItems should only apply for tuples

[jonaslagoni]

Describe the bug

Currently, additionalItems are applied even when the items are not a tuple.

https://datatracker.ietf.org/doc/html/draft-handrews-json-schema-validation-01#section-6.4.2

This means that this:

    "tags": {
      "type": "array",
      "items": {
        "$ref": "http://asyncapi.com/definitions/2.6.0/tag.json"
      },
      "uniqueItems": true
    },

generates this union type:

private _tags?: (Tag | any)[];

When it should only be:

private _tags?: Tag[];

[jonaslagoni]

The simple array type above makes sense.

But what about those tuples... Say we have this:

    "tags": {
      "type": "array",
      "items": [{type: string}, {type: boolean}],
      "additionalItems": true
    },

Would we expect to generate:

private _tags?: (string | boolean | any)[];

or rather a tuple and an array type in union 🤔

private _tags?: [string, boolean] | (string | boolean | any)[];

I am leaning towards the last option because the following input is valid:

{
  tags: ["teest", true, "test"]
}

Same with:

{
  tags: ["teest", true, false]
}

Same with:

{
  tags: ["teest", true]
}

And in most languages its either a tuple or array, it cant be partly tuple and partly array. So even though you lose the tuple structure for the array type (string | boolean | any)[] we get the best of both worlds IMO 🤔

[jonaslagoni]

Continued with tuple discussion here: #1139

[kennethaasan]

I've had issues with differences between draft 7 and draft 2020-12: https://ajv.js.org/json-schema.html#draft-2020-12
But I guess that's a different issue and should be handled by checking draft version

[jonaslagoni]

Gonna be solved in v2 and currently released as part of 2.0.0-next.4