Change Summary

This PR aims to complete #8944 and #8905 by also handling null types when generating a json-schema from a pydantic model.

For instance, the following model:

from pydantic import BaseModel
from typing import Literal


class Foo(BaseModel):
    bar: Literal["Bar"] = 'Bar'
    baz: Literal[None] = None
    foo: str = 'Foo'

leads to:

{'properties': {'bar': {'const': 'Bar', 'default': 'Bar', 'enum': ['Bar'], 'title': 'Bar', 'type': 'string'}, 'baz': {'const': None, 'default': None, 'enum': [None], 'title': 'Baz', 'type': 'null'}, 'foo': {'default': 'Foo', 'title': 'Foo', 'type': 'string'}}, 'title': 'Foo', 'type': 'object'}

Related issue number

fix #8905

Checklist

• The pull request title is a good summary of the changes - it will be used in the changelog
• Unit tests for the changes exist
• Tests pass on CI
• Documentation reflects the changes where applicable
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

Selected Reviewer: @adriangb