Getting type hints in `Field.__set_name__` can cause `RuntimeError`

[micuda]

Hi,
at first, thank You for the great library. =)

For code

from __future__ import annotations

from pyfields import field

class Foo:
  bar: Foo = field()

I got RuntimeError: Error calling __set_name__ on 'NativeField' instance 'bar' in 'Foo'. It is because class Foo does not exist yet and field calls typing.get_type_hints at line 299.

python-pyfields/pyfields/core.py

Lines 293 to 300 in e19ab12

	def __set_name__(self,
	owner, # type: Type[Any]
	name # type: str
	):
	if owner is not None:
	# fill all the information about how it is attached to the class
	cls_type_hints = get_type_hints(owner)
	self.set_as_cls_member(owner, name, owner_cls_type_hints=cls_type_hints)

For now I just don't annotate attributes like this, but it is weird (and inconsistent) that some attributes have typing annotation and some don't. =)

I'm not sure where and how to fix it.

[smarie]

Thanks @micuda for reporting this issue ! I'll have a look asap

[smarie]

So after investigating a bit: from __future__ import annotations is a special line introduced in PEP563 in order to enable python 3.10 behaviour in earlier versions. However this behaviour becomes similar to what happens when you use string type hints. So I am able to reproduce the issue without the PEP563:

from pyfields import field

class Foo:
  bar: 'Foo' = field()

I will fix this by enabling delayed type hint resolution.

[smarie]

Fixed in 1.3.0 (as well as field access from class #12, which was waiting a fix on pycharm side that is now available - I had to make the patch for them :) )