from __future__ import annotations causes ai functions to return strings #950
Description
First check
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- I used the GitHub search to try to find a similar issue and didn't find one.
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Bug summary
I was having a strange issue where ai functions were returning string data instead of the type specified in my function signature. It turns out that having from __future__ import annotations was causing the issue.
Reproduction
from __future__ import annotations # this causes the problem to appear
import inspect # we'll use this to look at why it's happening
import marvin
from pydantic import BaseModel
@marvin.fn
def recipe(
ingredients: list[str],
max_cook_time: int = 15,
cuisine: str = "North Italy",
experience_level: str = "beginner",
) -> Recipe:
"""
Returns a complete recipe that uses all the `ingredients` and
takes less than `max_cook_time` minutes to prepare. Takes
`cuisine` style and the chef's `experience_level` into account
as well.
"""
# get a recipe
my_recipe = recipe(["milk", "sugar", "flour"])
# verify the output is a Recipe
assert isinstance(my_recipe, Recipe)
# let's check the function signature
sig = inspect.signature(recipe)
# make sure it's output is a Recipe
assert type(sig.return_annotation) is RecipeError
No response
Versions
> marvin version
Version: 2.3.6
Python version: 3.11.4
OS/Arch: windows/amd64
Additional context
No response