482 lines
17 KiB
Python
482 lines
17 KiB
Python
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import inspect
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from dataclasses import _MISSING_TYPE, MISSING, Field, field, fields
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from functools import wraps
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from typing import (
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Any,
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Callable,
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Dict,
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List,
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Literal,
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Optional,
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Tuple,
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Type,
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TypeVar,
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Union,
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get_args,
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get_origin,
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overload,
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)
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from .errors import (
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StrictDataclassClassValidationError,
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StrictDataclassDefinitionError,
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StrictDataclassFieldValidationError,
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)
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Validator_T = Callable[[Any], None]
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T = TypeVar("T")
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# The overload decorator helps type checkers understand the different return types
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@overload
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def strict(cls: Type[T]) -> Type[T]: ...
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@overload
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def strict(*, accept_kwargs: bool = False) -> Callable[[Type[T]], Type[T]]: ...
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def strict(
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cls: Optional[Type[T]] = None, *, accept_kwargs: bool = False
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) -> Union[Type[T], Callable[[Type[T]], Type[T]]]:
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"""
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Decorator to add strict validation to a dataclass.
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This decorator must be used on top of `@dataclass` to ensure IDEs and static typing tools
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recognize the class as a dataclass.
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Can be used with or without arguments:
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- `@strict`
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- `@strict(accept_kwargs=True)`
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Args:
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cls:
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The class to convert to a strict dataclass.
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accept_kwargs (`bool`, *optional*):
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If True, allows arbitrary keyword arguments in `__init__`. Defaults to False.
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Returns:
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The enhanced dataclass with strict validation on field assignment.
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Example:
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```py
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>>> from dataclasses import dataclass
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>>> from huggingface_hub.dataclasses import as_validated_field, strict, validated_field
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>>> @as_validated_field
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>>> def positive_int(value: int):
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... if not value >= 0:
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... raise ValueError(f"Value must be positive, got {value}")
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>>> @strict(accept_kwargs=True)
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... @dataclass
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... class User:
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... name: str
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... age: int = positive_int(default=10)
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# Initialize
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>>> User(name="John")
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User(name='John', age=10)
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# Extra kwargs are accepted
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>>> User(name="John", age=30, lastname="Doe")
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User(name='John', age=30, *lastname='Doe')
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# Invalid type => raises
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>>> User(name="John", age="30")
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huggingface_hub.errors.StrictDataclassFieldValidationError: Validation error for field 'age':
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TypeError: Field 'age' expected int, got str (value: '30')
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# Invalid value => raises
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>>> User(name="John", age=-1)
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huggingface_hub.errors.StrictDataclassFieldValidationError: Validation error for field 'age':
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ValueError: Value must be positive, got -1
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```
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"""
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def wrap(cls: Type[T]) -> Type[T]:
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if not hasattr(cls, "__dataclass_fields__"):
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raise StrictDataclassDefinitionError(
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f"Class '{cls.__name__}' must be a dataclass before applying @strict."
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)
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# List and store validators
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field_validators: Dict[str, List[Validator_T]] = {}
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for f in fields(cls): # type: ignore [arg-type]
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validators = []
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validators.append(_create_type_validator(f))
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custom_validator = f.metadata.get("validator")
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if custom_validator is not None:
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if not isinstance(custom_validator, list):
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custom_validator = [custom_validator]
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for validator in custom_validator:
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if not _is_validator(validator):
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raise StrictDataclassDefinitionError(
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f"Invalid validator for field '{f.name}': {validator}. Must be a callable taking a single argument."
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)
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validators.extend(custom_validator)
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field_validators[f.name] = validators
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cls.__validators__ = field_validators # type: ignore
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# Override __setattr__ to validate fields on assignment
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original_setattr = cls.__setattr__
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def __strict_setattr__(self: Any, name: str, value: Any) -> None:
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"""Custom __setattr__ method for strict dataclasses."""
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# Run all validators
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for validator in self.__validators__.get(name, []):
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try:
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validator(value)
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except (ValueError, TypeError) as e:
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raise StrictDataclassFieldValidationError(field=name, cause=e) from e
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# If validation passed, set the attribute
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original_setattr(self, name, value)
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cls.__setattr__ = __strict_setattr__ # type: ignore[method-assign]
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if accept_kwargs:
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# (optional) Override __init__ to accept arbitrary keyword arguments
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original_init = cls.__init__
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@wraps(original_init)
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def __init__(self, **kwargs: Any) -> None:
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# Extract only the fields that are part of the dataclass
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dataclass_fields = {f.name for f in fields(cls)} # type: ignore [arg-type]
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standard_kwargs = {k: v for k, v in kwargs.items() if k in dataclass_fields}
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# Call the original __init__ with standard fields
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original_init(self, **standard_kwargs)
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# Add any additional kwargs as attributes
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for name, value in kwargs.items():
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if name not in dataclass_fields:
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self.__setattr__(name, value)
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cls.__init__ = __init__ # type: ignore[method-assign]
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# (optional) Override __repr__ to include additional kwargs
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original_repr = cls.__repr__
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@wraps(original_repr)
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def __repr__(self) -> str:
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# Call the original __repr__ to get the standard fields
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standard_repr = original_repr(self)
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# Get additional kwargs
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additional_kwargs = [
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# add a '*' in front of additional kwargs to let the user know they are not part of the dataclass
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f"*{k}={v!r}"
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for k, v in self.__dict__.items()
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if k not in cls.__dataclass_fields__ # type: ignore [attr-defined]
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]
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additional_repr = ", ".join(additional_kwargs)
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# Combine both representations
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return f"{standard_repr[:-1]}, {additional_repr})" if additional_kwargs else standard_repr
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cls.__repr__ = __repr__ # type: ignore [method-assign]
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# List all public methods starting with `validate_` => class validators.
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class_validators = []
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for name in dir(cls):
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if not name.startswith("validate_"):
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continue
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method = getattr(cls, name)
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if not callable(method):
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continue
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if len(inspect.signature(method).parameters) != 1:
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raise StrictDataclassDefinitionError(
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f"Class '{cls.__name__}' has a class validator '{name}' that takes more than one argument."
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" Class validators must take only 'self' as an argument. Methods starting with 'validate_'"
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" are considered to be class validators."
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)
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class_validators.append(method)
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cls.__class_validators__ = class_validators # type: ignore [attr-defined]
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# Add `validate` method to the class, but first check if it already exists
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def validate(self: T) -> None:
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"""Run class validators on the instance."""
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for validator in cls.__class_validators__: # type: ignore [attr-defined]
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try:
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validator(self)
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except (ValueError, TypeError) as e:
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raise StrictDataclassClassValidationError(validator=validator.__name__, cause=e) from e
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# Hack to be able to raise if `.validate()` already exists except if it was created by this decorator on a parent class
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# (in which case we just override it)
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validate.__is_defined_by_strict_decorator__ = True # type: ignore [attr-defined]
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if hasattr(cls, "validate"):
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if not getattr(cls.validate, "__is_defined_by_strict_decorator__", False): # type: ignore [attr-defined]
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raise StrictDataclassDefinitionError(
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f"Class '{cls.__name__}' already implements a method called 'validate'."
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" This method name is reserved when using the @strict decorator on a dataclass."
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" If you want to keep your own method, please rename it."
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)
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cls.validate = validate # type: ignore
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# Run class validators after initialization
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initial_init = cls.__init__
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@wraps(initial_init)
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def init_with_validate(self, *args, **kwargs) -> None:
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"""Run class validators after initialization."""
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initial_init(self, *args, **kwargs) # type: ignore [call-arg]
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cls.validate(self) # type: ignore [attr-defined]
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setattr(cls, "__init__", init_with_validate)
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return cls
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# Return wrapped class or the decorator itself
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return wrap(cls) if cls is not None else wrap
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def validated_field(
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validator: Union[List[Validator_T], Validator_T],
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default: Union[Any, _MISSING_TYPE] = MISSING,
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default_factory: Union[Callable[[], Any], _MISSING_TYPE] = MISSING,
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init: bool = True,
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repr: bool = True,
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hash: Optional[bool] = None,
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compare: bool = True,
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metadata: Optional[Dict] = None,
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**kwargs: Any,
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) -> Any:
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"""
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Create a dataclass field with a custom validator.
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Useful to apply several checks to a field. If only applying one rule, check out the [`as_validated_field`] decorator.
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Args:
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validator (`Callable` or `List[Callable]`):
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A method that takes a value as input and raises ValueError/TypeError if the value is invalid.
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Can be a list of validators to apply multiple checks.
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**kwargs:
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Additional arguments to pass to `dataclasses.field()`.
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Returns:
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A field with the validator attached in metadata
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"""
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if not isinstance(validator, list):
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validator = [validator]
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if metadata is None:
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metadata = {}
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metadata["validator"] = validator
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return field( # type: ignore
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default=default, # type: ignore [arg-type]
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default_factory=default_factory, # type: ignore [arg-type]
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init=init,
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repr=repr,
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hash=hash,
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compare=compare,
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metadata=metadata,
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**kwargs,
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)
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def as_validated_field(validator: Validator_T):
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"""
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Decorates a validator function as a [`validated_field`] (i.e. a dataclass field with a custom validator).
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Args:
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validator (`Callable`):
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A method that takes a value as input and raises ValueError/TypeError if the value is invalid.
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"""
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def _inner(
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default: Union[Any, _MISSING_TYPE] = MISSING,
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default_factory: Union[Callable[[], Any], _MISSING_TYPE] = MISSING,
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init: bool = True,
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repr: bool = True,
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hash: Optional[bool] = None,
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compare: bool = True,
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metadata: Optional[Dict] = None,
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**kwargs: Any,
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):
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return validated_field(
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validator,
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default=default,
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default_factory=default_factory,
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init=init,
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repr=repr,
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hash=hash,
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compare=compare,
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metadata=metadata,
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**kwargs,
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)
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return _inner
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def type_validator(name: str, value: Any, expected_type: Any) -> None:
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"""Validate that 'value' matches 'expected_type'."""
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origin = get_origin(expected_type)
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args = get_args(expected_type)
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if expected_type is Any:
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return
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elif validator := _BASIC_TYPE_VALIDATORS.get(origin):
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validator(name, value, args)
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elif isinstance(expected_type, type): # simple types
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_validate_simple_type(name, value, expected_type)
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else:
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raise TypeError(f"Unsupported type for field '{name}': {expected_type}")
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def _validate_union(name: str, value: Any, args: Tuple[Any, ...]) -> None:
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"""Validate that value matches one of the types in a Union."""
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errors = []
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for t in args:
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try:
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type_validator(name, value, t)
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return # Valid if any type matches
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except TypeError as e:
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errors.append(str(e))
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raise TypeError(
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f"Field '{name}' with value {repr(value)} doesn't match any type in {args}. Errors: {'; '.join(errors)}"
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)
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def _validate_literal(name: str, value: Any, args: Tuple[Any, ...]) -> None:
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"""Validate Literal type."""
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if value not in args:
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raise TypeError(f"Field '{name}' expected one of {args}, got {value}")
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def _validate_list(name: str, value: Any, args: Tuple[Any, ...]) -> None:
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"""Validate List[T] type."""
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if not isinstance(value, list):
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raise TypeError(f"Field '{name}' expected a list, got {type(value).__name__}")
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# Validate each item in the list
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item_type = args[0]
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for i, item in enumerate(value):
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try:
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type_validator(f"{name}[{i}]", item, item_type)
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except TypeError as e:
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raise TypeError(f"Invalid item at index {i} in list '{name}'") from e
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def _validate_dict(name: str, value: Any, args: Tuple[Any, ...]) -> None:
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"""Validate Dict[K, V] type."""
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if not isinstance(value, dict):
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raise TypeError(f"Field '{name}' expected a dict, got {type(value).__name__}")
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# Validate keys and values
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||
|
|
key_type, value_type = args
|
||
|
|
for k, v in value.items():
|
||
|
|
try:
|
||
|
|
type_validator(f"{name}.key", k, key_type)
|
||
|
|
type_validator(f"{name}[{k!r}]", v, value_type)
|
||
|
|
except TypeError as e:
|
||
|
|
raise TypeError(f"Invalid key or value in dict '{name}'") from e
|
||
|
|
|
||
|
|
|
||
|
|
def _validate_tuple(name: str, value: Any, args: Tuple[Any, ...]) -> None:
|
||
|
|
"""Validate Tuple type."""
|
||
|
|
if not isinstance(value, tuple):
|
||
|
|
raise TypeError(f"Field '{name}' expected a tuple, got {type(value).__name__}")
|
||
|
|
|
||
|
|
# Handle variable-length tuples: Tuple[T, ...]
|
||
|
|
if len(args) == 2 and args[1] is Ellipsis:
|
||
|
|
for i, item in enumerate(value):
|
||
|
|
try:
|
||
|
|
type_validator(f"{name}[{i}]", item, args[0])
|
||
|
|
except TypeError as e:
|
||
|
|
raise TypeError(f"Invalid item at index {i} in tuple '{name}'") from e
|
||
|
|
# Handle fixed-length tuples: Tuple[T1, T2, ...]
|
||
|
|
elif len(args) != len(value):
|
||
|
|
raise TypeError(f"Field '{name}' expected a tuple of length {len(args)}, got {len(value)}")
|
||
|
|
else:
|
||
|
|
for i, (item, expected) in enumerate(zip(value, args)):
|
||
|
|
try:
|
||
|
|
type_validator(f"{name}[{i}]", item, expected)
|
||
|
|
except TypeError as e:
|
||
|
|
raise TypeError(f"Invalid item at index {i} in tuple '{name}'") from e
|
||
|
|
|
||
|
|
|
||
|
|
def _validate_set(name: str, value: Any, args: Tuple[Any, ...]) -> None:
|
||
|
|
"""Validate Set[T] type."""
|
||
|
|
if not isinstance(value, set):
|
||
|
|
raise TypeError(f"Field '{name}' expected a set, got {type(value).__name__}")
|
||
|
|
|
||
|
|
# Validate each item in the set
|
||
|
|
item_type = args[0]
|
||
|
|
for i, item in enumerate(value):
|
||
|
|
try:
|
||
|
|
type_validator(f"{name} item", item, item_type)
|
||
|
|
except TypeError as e:
|
||
|
|
raise TypeError(f"Invalid item in set '{name}'") from e
|
||
|
|
|
||
|
|
|
||
|
|
def _validate_simple_type(name: str, value: Any, expected_type: type) -> None:
|
||
|
|
"""Validate simple type (int, str, etc.)."""
|
||
|
|
if not isinstance(value, expected_type):
|
||
|
|
raise TypeError(
|
||
|
|
f"Field '{name}' expected {expected_type.__name__}, got {type(value).__name__} (value: {repr(value)})"
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
def _create_type_validator(field: Field) -> Validator_T:
|
||
|
|
"""Create a type validator function for a field."""
|
||
|
|
# Hacky: we cannot use a lambda here because of reference issues
|
||
|
|
|
||
|
|
def validator(value: Any) -> None:
|
||
|
|
type_validator(field.name, value, field.type)
|
||
|
|
|
||
|
|
return validator
|
||
|
|
|
||
|
|
|
||
|
|
def _is_validator(validator: Any) -> bool:
|
||
|
|
"""Check if a function is a validator.
|
||
|
|
|
||
|
|
A validator is a Callable that can be called with a single positional argument.
|
||
|
|
The validator can have more arguments with default values.
|
||
|
|
|
||
|
|
Basically, returns True if `validator(value)` is possible.
|
||
|
|
"""
|
||
|
|
if not callable(validator):
|
||
|
|
return False
|
||
|
|
|
||
|
|
signature = inspect.signature(validator)
|
||
|
|
parameters = list(signature.parameters.values())
|
||
|
|
if len(parameters) == 0:
|
||
|
|
return False
|
||
|
|
if parameters[0].kind not in (
|
||
|
|
inspect.Parameter.POSITIONAL_OR_KEYWORD,
|
||
|
|
inspect.Parameter.POSITIONAL_ONLY,
|
||
|
|
inspect.Parameter.VAR_POSITIONAL,
|
||
|
|
):
|
||
|
|
return False
|
||
|
|
for parameter in parameters[1:]:
|
||
|
|
if parameter.default == inspect.Parameter.empty:
|
||
|
|
return False
|
||
|
|
return True
|
||
|
|
|
||
|
|
|
||
|
|
_BASIC_TYPE_VALIDATORS = {
|
||
|
|
Union: _validate_union,
|
||
|
|
Literal: _validate_literal,
|
||
|
|
list: _validate_list,
|
||
|
|
dict: _validate_dict,
|
||
|
|
tuple: _validate_tuple,
|
||
|
|
set: _validate_set,
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
__all__ = [
|
||
|
|
"strict",
|
||
|
|
"validated_field",
|
||
|
|
"Validator_T",
|
||
|
|
"StrictDataclassClassValidationError",
|
||
|
|
"StrictDataclassDefinitionError",
|
||
|
|
"StrictDataclassFieldValidationError",
|
||
|
|
]
|