Field Validator Order Changes with Lists of Tuples

[aleewen]

Initial Checks
I confirm that I'm using Pydantic V2
Description
Hi all,

I have a field that is a list of some data type or a tuple. When passing in that data type, it works fine. However, when passing in a list of tuples, it's almost like the validation order changes; the ValidationInfo dictionary key is unset, resulting in a KeyError.

Example Code

from typing import Optional
from pydantic import BaseModel, ValidationInfo, Field, field_validator


class TestModel(BaseModel):
    
    my_list: list[int | tuple[int]]
    my_dict: dict[int | tuple[int], str] = Field(default=None, validate_default=True)
    
    @field_validator('my_list', mode='before')
    @classmethod
    def validate_list(cls,
                      value: list[int | tuple[int]]) -> list[int | tuple[int]]:
        """
        THIS SHOULD GO FIRST.
        """
        return value

    @field_validator('my_dict', mode='before')
    @classmethod
    def validate_dict(cls,
                      value: Optional[dict[int | tuple[int], str]],
                      instance: ValidationInfo) -> dict[int | tuple[int], str]:
        """
        THIS SHOULD GO SECOND.
        """
        print_me = instance.data['my_list'] # KEY ERROR HERE
        print(print_me)
        
        if value is None:
            return {}
        else:
            return value
    


# This works; print shows successfully
test_model = TestModel(my_list=[1, 2])

# This DOESN'T work; KeyError
test_model = TestModel(my_list=[(1, 2)])

Python, Pydantic & OS Version
pydantic version: 2.7.0
pydantic-core version: 2.18.1
pydantic-core build: profile=release pgo=true
install path: C:\Users\aleewen.pyenv\pyenv-win\versions\3.11.8\Lib\site-packages\pydantic
python version: 3.11.8 (tags/v3.11.8:db85d51, Feb 6 2024, 22:03:32) [MSC v.1937 64 bit (AMD64)]
platform: Windows-10-10.0.19045-SP0
related packages: pydantic-settings-2.2.1 typing_extensions-4.10.0
commit: unknown

[aleewen]

(Sorry, I tried to edit it but ended up messing up the formatting)

[aleewen]

Learning now that this issue goes away when specifying flexible length with ellipses: tuple[int, ...]

But will leave this open because I doubt that this is intended behavior: to change the validation order and raise a KeyError when the length of the provided tuple does not match the one required by the field. I would assume it would be more appropriate to raise a ValidationError