Discriminated union with a List: annotation is on the list, not the union
Describe the bug
Generation of list/array of discriminated union annotates the list, not the union. Same problem with = Field(..., discriminator) too if you don't use annotated.
To Reproduce
Example schema:
{
"$schema": "http://json-schema.org/draft-04/schema#",
"title": "SomeTest",
"type": "object",
"required": [
"some_array"
],
"properties": {
"some_array": {
"type": "array",
"items": {
"discriminator": {
"propertyName": "discrim",
"mapping": {
"Type1": "#/definitions/FeatureType1",
"Type2": "#/definitions/FeatureType2"
}
},
"oneOf": [
{
"$ref": "#/definitions/FeatureType1"
},
{
"$ref": "#/definitions/FeatureType2"
}
]
}
}
},
"definitions": {
"FeatureType1": {
"type": "object",
"properties": {
"discrim": {
"type": "string"
},
"id": {
"type": "string"
}
}
},
"FeatureType2": {
"type": "object",
"properties": {
"discrim": {
"type": "string"
},
"id": {
"type": "string"
},
"something_else": {
"type": "string"
}
}
}
}
}Used commandline:
$ datamodel-codegen --disable-timestamp --use-annotated --collapse-root-models --target-python-version '3.11' --input ../schema.json --input-file-type jsonschema --output whatever.py
This gives:
# generated by datamodel-codegen:
# filename: schema.json
from __future__ import annotations
from typing import Annotated, List, Literal, Optional, Union
from pydantic import BaseModel, Field
class FeatureType1(BaseModel):
discrim: Literal['Type1']
id: Optional[str] = None
class FeatureType2(BaseModel):
discrim: Literal['Type2']
id: Optional[str] = None
something_else: Optional[str] = None
class SomeTest(BaseModel):
some_array: Annotated[
List[Union[FeatureType1, FeatureType2]], Field(discriminator='discrim')
]This doesn't work:
TypeError: `discriminator` can only be used with `Union` type with more than one variant`
Expected behavior
The problem is that the Annotation should be on the Union, not on the list, so the SomeTest class should be:
class SomeTest(BaseModel):
some_array: List[
Annotated[Union[FeatureType1, FeatureType2], Field(discriminator='discrim')]
]And now it works. Note that we get more or less the same problem if you remove --use-annotated
Version:
- OS: Windows 11
- Python version: 3.11
- datamodel-code-generator version: 0.25.4
Additional context
Thanks!
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