What exactly replaces resolve_xxx(self) in V1 ?

[GTorreil]

Hey there,
Congratulations for releasing V1 :)

I'm migrating my app to it, but there's something I don't really understand.
The documentation here says :

resolve_xxx(self, ...) - support resolve with (self) is dropped in favor of pydantic build-in functionality

What is the pydantic functionnality that replaces it ?

[vitalik]

Hi @GTorreil

it's "Computed Field"

from pydantic import BaseModel, computed_field


class Rectangle(BaseModel):
    width: int
    length: int

    @computed_field
    @property
    def area(self) -> int:
        return self.width * self.length


print(Rectangle(width=3, length=2).model_dump())
#> {'width': 3, 'length': 2, 'area': 6}

[GTorreil]

Hey @vitalik , sorry for the ping, but I still can't find how to compute fields based on arbitrary properties of the ORM instance. For instance, being able to populate a schema field with [user.id for user in instance.users] .
I hope this is clear ! cheers

[vitalik]

I would use the resolve (static) then:

class Some(Schema):
    id: int
    user_ids: list[int]

    @staticmethod
    def resolve_user_ids(instance):
         return [user.id for user in instance.users]

[yshalsager]

I am having the same problem and the suggestion @vitalik provided doesn't work for me unfortunately, my use case requires accessing a private field inside resolver like this:

class Folder(Schema):
    _app = sys.modules[get_app_name(__package__)]

    id: int
	…
    folders: list[dict[str, Any]] | None = None
    
    def resolve_folders(self, folder, context):
        if 'folders' not in get_include_query(context):
            return None
        request = context['request']
        # access self._app here for some checks

Is there a better/recommended way rather than non-static resovler?

[GTorreil]

@yshalsager , resolvers are static methods. AFAIK they do not access the schema instance. The argument they get is the instance that was passed to from_orm, not the schema instance itself.

For this usecase, Pydantic computed fields should work.

[yshalsager]

For this usecase, Pydantic computed fields should work.

@GTorreil cirrect, but computed fields can't access object or context, which I need to access beside the private field.