from typing import Literal

from pydantic import BaseModel


class Cat(BaseModel):
    type: Literal['cat']
    color: str | None = None  # field with default


class Dog(BaseModel):
    type: Literal['dog']


class Zoo(BaseModel):
    animals: list[Cat | Dog]


cat = Cat(type='cat')
zoo = Zoo(animals=[cat])

# Sanity check: model_dump without exclude_unset works fine
assert zoo.model_dump() == {'animals': [{'type': 'cat', 'color': None}]}

# Sanity check: model_dump(exclude_unset=True) on the Cat alone works fine
assert cat.model_dump(exclude_unset=True) == {'type': 'cat'}

# BUG: model_dump(exclude_unset=True) on the parent Zoo produces warnings
assert zoo.model_dump(exclude_unset=True) == {'animals': [{'type': 'cat'}]}