References are broken for JSON schema (0.4.0)

Checklist

• The bug is reproducible against the latest release and/or master.
• There are no similar issues or pull requests to fix it yet.

Describe the bug

Quoting the following change from the changelog for 0.4.0:

Update JSON schema ref according to OAS 3: #/components/schemas/

Currently I’m facing the issue that when a typesystem schema contains a reference, it will not be resolvable in the resulting JSON Schema. I made an example based on https://github.com/encode/typesystem/blob/master/docs/references.md.

To reproduce

import json
import typesystem

definitions = typesystem.Definitions()

artist_schema = typesystem.Schema(fields={"name": typesystem.String(max_length=100)})

album_schema = typesystem.Schema(
    fields={
        "title": typesystem.String(max_length=100),
        "release_date": typesystem.Date(),
        "artist": typesystem.Reference(to="Artist", definitions=definitions),
    }
)

definitions["Artist"] = artist_schema
definitions["Album"] = album_schema

document = typesystem.to_json_schema(album_schema)
print(json.dumps(document, indent=4))

I’m simply trying to get a JSON Schema out of the defined album_schema.

Expected behavior

Receive a JSON Schema output that contains the correct $ref which makes it resolvable.

Actual behavior

JSON Schema output that contains a definitions key which is not in line with the new syntax (i.e.: "$ref": "#/components/schemas/Artist")

{
    "type": "object",
    "properties": {
        "title": {
            "type": "string",
            "minLength": 1,
            "maxLength": 100
        },
        "release_date": {
            "type": "string",
            "minLength": 1,
            "format": "date"
        },
        "artist": {
            "$ref": "#/components/schemas/Artist"
        }
    },
    "required": [
        "title",
        "release_date",
        "artist"
    ],
    "definitions": {
        "Artist": {
            "type": "object",
            "properties": {
                "name": {
                    "type": "string",
                    "minLength": 1,
                    "maxLength": 100
                }
            },
            "required": [
                "name"
            ]
        }
    }
}

With the newly generated reference syntax (“#/components/schemas/Artist”), shouldn’t the document contain the elements “components” as well as “schemas” and respectively “Artist” in this example?

Environment

• OS: macOS
• Python version: 3.9.6
• Typesystem version: 0.4.0

[aminalaee]

It’s released now.

[aminalaee]

The output will be like this now:

{
    "type": "object",
    "properties": {
        "title": {
            "type": "string",
            "minLength": 1,
            "maxLength": 100
        },
        "release_date": {
            "type": "string",
            "minLength": 1,
            "format": "date"
        },
        "artist": {
            "$ref": "#/components/schemas/Artist"
        }
    },
    "required": [
        "title",
        "release_date",
        "artist"
    ],
    "components": {
        "schemas": {
            "Artist": {
                "type": "object",
                "properties": {
                    "name": {
                        "type": "string",
                        "minLength": 1,
                        "maxLength": 100
                    }
                },
                "required": [
                    "name"
                ]
            }
        }
    }
}