Validation fails on an empty list

[dhimmel]

The following model validation fails on an empty list:

import polars as pl
from patito import Model

class TestModel(Model):
    list_field: list[str]

df = pl.DataFrame({"list_field": [["a", "b"], []]})
TestModel.validate(df)

With the error message:

DataFrameValidationError: 1 validation error for TestModel
list_field
  1 missing value in lists (type=value_error.missingvalues)

I would expect an empty list to validate as list[str], at least Pydantic thinks so:

from pydantic import BaseModel

class TestPydanticModel(BaseModel):
    list_field: list[str]

TestPydanticModel(list_field=[])  # happy

[dhimmel]

Changing to list_field: list[str | None] passes validation.

[dsgibbons]

Can you please rerun this from the main branch instead of the latest release and see if this is still an issue? If this is still an issue, it should be a pretty easy fix.

[dsgibbons]

Ok I confirm this is present on main. Thank you for raising this.