Question about name resolution when $id is used

[Simon Sprott]

Im trying to figure out how to resolve references within a JSON Schema, when $id properties are involved.

I'm looking at the example in https://tools.ietf.org/html/draft-handrews-json-schema-01#section-8.2.4 whats described in there makes sense, but does not provide a complete explaination, so I've added definitions "Z", to the example to help explain.

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "$id": "http://example.com/root.json",
    "definitions": {
        "A": {
            "$id": "#foo"
        },
        "B": {
            "$id": "other.json",
            "definitions": {
                "X": {
                    "$id": "#bar",
                    "definitions": {
                        "Z": {
                            "type": "integer"
                        }
                    }
                },
                "Y": {
                    "$id": "t/inner.json"
                }
            }
        },
        "C": {
            "$id": "urn:uuid:ee564b8a-7a87-4125-8c96-e9f123d6766f"
        }
    }
}

According to the spec the following are valid references to "X"

   #/definitions/B/definitions/X

         http://example.com/other.json#bar

         http://example.com/other.json#/definitions/X

         http://example.com/root.json#/definitions/B/definitions/X

What I'm stuggling to figure out is what valid references to "Z" would look like

   #/definitions/B/definitions/X/definitions/Z

         http://example.com/other.json#bar/definitions/Z                          - not at all sure about this

         http://example.com/other.json#/definitions/X/definitions/Z               - this seesms like a logical progression

         http://example.com/root.json#/definitions/B/definitions/X/definitions/Z  - Happy with this one

Thanks for your help