Pydantic: Support for types annotated with Field(default_factory)

[Joshua Noeske (PatrickJosh)]

Hi, when using Pydantic, I can annotate the type of an attribute with Field(default_factory) to provide a function for setting default values if the caller did not supply a value for that attribute. See the following example:

from typing import Annotated
from pydantic import Field
from pydantic.dataclasses import dataclass


@dataclass(kw_only=True)
class Test:
    item: Annotated[list[str], Field(default_factory=list)]


t = Test()  # Pyright: Argument missing for parameter "item"

Pyright produces an error on calling Test() with no arguments although the specified default_factory automatically provides a default value.

In the Pydantic docs, it is actually noted that static type checkers do not support this pattern, see the annotated pattern.

Since I've not found any discussions on this, I'd like to ask, might it be possible to add support for this pattern to Pyright or is there anything that prevents this from being added?