Cannot generate JSON Schema for a model with generic class

test_comma_separated_query_strings.py

from enum import Enum
from typing import Optional, Generic, TypeVar, Set

from pydantic import BaseModel, version
from pydantic.fields import ModelField
from pydantic.schema import model_schema

ContainerType = TypeVar('ContainerType')


class Color(str, Enum):
    """Cat colors."""

    RED = 'red'
    WHITE = 'white'
    BLACK = 'black'


class CommaSeparated(Generic[ContainerType]):
    """Comma separated values of a container."""

    @classmethod
    def __get_validators__(cls):
        """Ensure pydantic compatibility."""
        yield cls.validate

    @classmethod
    def validate(cls, raw_value: str, field: ModelField) -> ContainerType:
        """Validate the raw value."""
        raise ValueError(
            'I will write this validation later, too lazy right now :(',
        )


class CatsQuery(BaseModel):
    """Query our cats herd."""

    color__in: Optional[CommaSeparated[Set[Color]]] = None


print(f'Pydantic version: {version.VERSION}')
model_schema(CatsQuery)

'''
Output:

    Pydantic version: 1.7.3
    
    tests/test_comma_separated_query_strings.py:None (tests/test_comma_separated_query_strings.py)
    test_comma_separated_query_strings.py:42: in <module>
        model_schema(CatsQuery)
    ../venv/lib/python3.8/site-packages/pydantic/schema.py:153: in model_schema
        m_schema, m_definitions, nested_models = model_process_schema(
    ../venv/lib/python3.8/site-packages/pydantic/schema.py:525: in model_process_schema
        m_schema, m_definitions, nested_models = model_type_schema(
    ../venv/lib/python3.8/site-packages/pydantic/schema.py:566: in model_type_schema
        f_schema, f_definitions, f_nested_models = field_schema(
    ../venv/lib/python3.8/site-packages/pydantic/schema.py:222: in field_schema
        f_schema, f_definitions, f_nested_models = field_type_schema(
    ../venv/lib/python3.8/site-packages/pydantic/schema.py:475: in field_type_schema
        assert field.shape == SHAPE_SINGLETON, field.shape
    E   AssertionError: 10
'''