Bug: Strange behavior with self-reference model

[FredrikBakken]

Description

Encountering some strange errors with self-referencing models.

In the first case, there seems to be a 50/50 chance for the pytest to work:

from __future__ import annotations
from typing import Optional, Dict

import pydantic as pyd

from polyfactory.factories.pydantic_factory import ModelFactory

class Bar(pyd.BaseModel):
    fields: Dict[str, Foo] = pyd.Field(default_factory=dict)

class Foo(pyd.BaseModel):
    sometimes: Optional[Bar] = pyd.Field(default=None, exclude=True)
    # never: Dict[str, Bar] = pyd.Field(default_factory=dict)

class FooFactory(ModelFactory[Foo]):
    __model__ = Foo

def test_foo():
    foo_instance = FooFactory.build()
    assert isinstance(foo_instance, Foo)

In the second case, the pytest seems to never work:

from __future__ import annotations
from typing import Optional, Dict

import pydantic as pyd

from polyfactory.factories.pydantic_factory import ModelFactory

class Bar(pyd.BaseModel):
    fields: Dict[str, Foo] = pyd.Field(default_factory=dict)

class Foo(pyd.BaseModel):
    # sometimes: Optional[Bar] = pyd.Field(default=None, exclude=True)
    never: Dict[str, Bar] = pyd.Field(default_factory=dict)

class FooFactory(ModelFactory[Foo]):
    __model__ = Foo

def test_foo():
    foo_instance = FooFactory.build()
    assert isinstance(foo_instance, Foo)

Release Version

2.16.2

Platform

• [X] Linux
• [ ] Mac
• [ ] Windows
• [ ] Other (Please specify in the description above)

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[adhtruong]

Thanks for reporting @FredrikBakken .

• The first case for optional is definitely a bug and PR is in
• Second case is a little trickier. For a workaround in the meantime setting never = {} should work and would be the behaviour. Right now polyfactory doesn't support nested recursive models other than in trivial cases where there is an obvious out e.g. choosing None in the case of the sometimes in the example.