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field: Schema | None = None should generate anyOf where null is the last item #1027
Description
Hi 👋
I am using msgspec to generate JsonSchema for my schemas in wemake-services/django-modern-rest#990
But, there's a big difference with how msgspec and pydantic generates schema for this type:
class _TailsSchema(pydantic.BaseModel):
id: int
name: str
class _UserCreateModel(pydantic.BaseModel):
tails: _TailsSchema | None = Nonevs
class _TailsSchema(msgspec.Struct):
id: int
name: str
class _UserCreateModel(msgspec.Struct):
tails: _TailsSchema | None = NoneWhat schema is generated
pydantic:
"_UserCreateModel": {
"properties": {
"tails": {
"anyOf": [
{
"$ref": "#/components/schemas/_TailsSchema"
},
{
"type": "null"
}
]
},
// ...
}msgspec:
"_UserCreateModel": {
"properties": {
"tails": {
"anyOf": [
{
"type": "null"
},
{
"$ref": "#/components/schemas/_TailsSchema"
}
]
},
// ...
}The final result from msgspec makes Swagger to render
{
"email": "string",
"tail": null,
"tail_optional": null
}as the example value, which is correct, but less ideal than the pydantic's version:
{
"email": "string",
"tail": {
"id": 0,
"name": "string"
},
"tail_optional": {
"id": 0,
"name": "string"
}
}Looks like that Swagger just takes the first value from anyOf, it would be reasonable to change the order. It would also be more semantically similar to how Schema | None is used in Python, not None | Schema
Activity
place `null` last in `anyOf` for optional unions in JSON schema (msgs…