[BUG:PEP563] tortoise.contrib.pydantic.utils.get_annotations uses incorrect global namespace

[WizzyGeek]

What Happened

from __future__ import annotations

from tortoise import fields
...

class R2Container(Model):
    problem: fields.ForeignKeyRelation[R2Problem] = ...
    ports: fields.ReverseRelation[R2Ports]
...

...
# In yet another file
Tortoise.init_models(["somewhere"], "models")
R2Container_Pydantic = pydantic_model_creator(R2Container)

Raises

Traceback (most recent call last):
  [Leaving these frames for readability]
  File "/home/WizzyGeek/code/lug/pwncore/src/pwncore/models/__init__.py", line 69, in <module>
    R2Container_Pydantic = pydantic_model_creator(R2Container)
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/WizzyGeek/code/lug/pwncore/.venv/lib/python3.11/site-packages/tortoise/contrib/pydantic/creator.py", line 226, in pydantic_model_creator
    annotations = get_annotations(cls)
                  ^^^^^^^^^^^^^^^^^^^^
  File "/home/WizzyGeek/code/lug/pwncore/.venv/lib/python3.11/site-packages/tortoise/contrib/pydantic/utils.py", line 18, in get_annotations
    return typing.get_type_hints(method or cls, globalns=globalns)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/typing.py", line 2358, in get_type_hints
    value = _eval_type(value, base_globals, base_locals)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/typing.py", line 381, in _eval_type
    return t._evaluate(globalns, localns, recursive_guard)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/typing.py", line 891, in _evaluate
    eval(self.__forward_code__, globalns, localns),
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<string>", line 1, in <module>
NameError: name 'fields' is not defined

Proposed Solution 1

https://github.com/tortoise/tortoise-orm/blob/53376c9032800770711f7a305ae971cba038b77f/tortoise/contrib/pydantic/utils.py#L17-L18

Removal of line 17 fixes the issue since the globalns goes back to the actual namespace of the object otherwise if this line is kept the namespace (both local and global) are replaced with the app namespace meaning the code for the annotations can only access models (afaik)

This solution changes behavior but I have not seen the current behavior documented or used anywhere yet.

Proposed Solution 2

Deal with internals of typing.get_type_hints and extend the globalns with app namespace

I can create a PR depending on which solution is preferred, there are also other ways if neither of the solutions are acceptable.

Workaround

Here is a DI

import tortoise
def get_annotations(cls, method = None):
    return typing.get_type_hints(method or cls)

tortoise.contrib.pydantic.utils.get_annotations = get_annotations
tortoise.contrib.pydantic.creator.get_annotations = get_annotations