Expected type not working

[loganripplinger]

Repro steps

I am using schemas generated from protobufs via protoc-gen-jsonschema.

I am using JSON4 not JSON5.

Use this schema to reproduce the problem show below:

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "definitions": {
        "foo": {
            "properties": {
                "number": {
                    "oneOf": [
                        {
                            "type": "integer"
                        },
                        {
                            "type": "null"
                        }
                    ]
                }
            },
            "additionalProperties": false,
            "oneOf": [
                {
                    "type": "null"
                },
                {
                    "type": "object"
                }
            ]
        }},
    "properties": {
        "foo": {
            "$ref": "#/definitions/foo",
            "additionalProperties": false,
            "oneOf": [
                {
                    "type": "null"
                },
                {}
            ]
        }
    },
    "additionalProperties": false,
    "oneOf": [
        {
            "type": "null"
        },
        {
            "type": "object"
        }
    ]
}

I further narrowed it down to this schema (in JS/JSON5 instead of JSON4, though I am still using the JSON4 plugin):

{
  $schema: 'http://json-schema.org/draft-04/schema#',
  properties: {
    foo: {
      additionalProperties: false,
      properties: {
        number: {
          type: 'integer',
        },
      },
      oneOf: [
        {
          type: 'null',
        },
        {
          type: 'object'
        },
      ],
    },
  },
  additionalProperties: false,
  oneOf: [
    {
      type: 'null',
    },
    {
      type: 'object',
    },
  ],
}

Of note if you remove properties.oneOf and instead just use type: 'object' it will correctly show the error:

{
  $schema: 'http://json-schema.org/draft-04/schema#',
  properties: {
    foo: {
      additionalProperties: false,
      properties: {
        number: {
          type: 'integer',
        },
      },
      type: 'object'
    },
  },
  additionalProperties: false,
  oneOf: [
    {
      type: 'null',
    },
    {
      type: 'object',
    },
  ],
}

Expected Behavior

An error should appear.

Actual Behavior

No error appears.

[acao]

I will look into this bug - thanks for reporting! I didn't know oneOf could be represented this way tbh, haha! I see this is valid, but usually I would do this (I wonder if this also isn't working?)

{
  $schema: 'http://json-schema.org/draft-04/schema#',
  properties: {
    foo: {
      oneOf: [
        {
           type: 'object',
           additionalProperties: false,
            properties: {
              number: {
                 type: 'integer',
              },
           },
        {
          type: 'null'
        },
      ],
    },
  },
  additionalProperties: false,
  oneOf: [
    {
      type: 'null',
    },
    {
      type: 'object',
    },
  ],
}

but your generated schema def is also valid. I will see what I can do, starting with some tests!

[acao]

this one is going to take some time because it requires rewriting some of our pointer functions to pick up the root # as a pointer, which ends up breaking a lot of functionality that as it turns out was based on skipping # accidentally.

@imolorhe what do you think of making the object root a pointer - i think it will solve issues like these ultimately, and thus we can be in compatibility with some major json schema specs that have top level complex types or refs (top level $ref or top level complex types)

[imolorhe]

No issues there from me.

[imolorhe]

I dug into this a bit further, and I think the issue is upstream in json-schema-library. I've created an issue there.