Allow forwardRefs

[SolAstri]

I have a code like this:

from odmantic import Field, Model, EmbeddedModel, Reference
from typing import List

class Revision(EmbeddedModel):
    modified_by: "User" = Reference()

class User(Model):
    revisions: List[Revision]

It yields this error:

Traceback (most recent call last):
  File "..../api/m_example.py", line 4, in <module>
    class Revision(EmbeddedModel):
  File ".../lib/python3.8/site-packages/odmantic/model.py", line 443, in __new__
    mcs.__validate_cls_namespace__(name, namespace)
  File .../lib/python3.8/site-packages/odmantic/model.py", line 290, in __validate_cls_namespace__
    parse_obj_as(field_type, value)
  File "pydantic/tools.py", line 35, in pydantic.tools.parse_obj_as
  File "pydantic/main.py", line 360, in pydantic.main.BaseModel.__init__
  File "pydantic/main.py", line 955, in pydantic.main.validate_model
pydantic.errors.ConfigError: field "__root__" not yet prepared so type is still a ForwardRef, you might need to call ParsingModel[ForwardRef('User')].update_forward_refs().

[art049]

Yes actually calling update_forward_refs() would be needed while initializing the model.

However, it would allow to create cyclic references. This is currently not handled as the references are eager for now

[SolAstri]

Is it possible to make cyclic references now?

[gagandeep]

In my self-referential model case even update_forward_refs not working. It's look something like following

from __future__ import annotations

class Task(Model):
    source_task: Task = Reference()

Task.update_forward_refs()

If I am removing = Reference() then its working fine.