Validate Call

Decorator for validating function calls.

validate_call

validate_call(
    func: AnyCallableT | None = None,
    /,
    *,
    config: ConfigDict | None = None,
    validate_return: bool = False,
) -> AnyCallableT | Callable[[AnyCallableT], AnyCallableT]

Usage Documentation

Validation Decorator

Returns a decorated wrapper around the function that validates the arguments and, optionally, the return value.

Usage may be either as a plain decorator @validate_call or with arguments @validate_call(...).

Parameters:

Name	Type	Description	Default
func	AnyCallableT | None	The function to be decorated.	None
config	ConfigDict | None	The configuration dictionary.	None
validate_return	bool	Whether to validate the return value.	False

Returns:

Type	Description
AnyCallableT | Callable[[AnyCallableT], AnyCallableT]	The decorated function.

Source code in pydantic/validate_call_decorator.py

def validate_call(
    func: AnyCallableT | None = None,
    /,
    *,
    config: ConfigDict | None = None,
    validate_return: bool = False,
) -> AnyCallableT | Callable[[AnyCallableT], AnyCallableT]:
    """Usage docs: https://docs.pydantic.dev/2.9/concepts/validation_decorator/

    Returns a decorated wrapper around the function that validates the arguments and, optionally, the return value.

    Usage may be either as a plain decorator `@validate_call` or with arguments `@validate_call(...)`.

    Args:
        func: The function to be decorated.
        config: The configuration dictionary.
        validate_return: Whether to validate the return value.

    Returns:
        The decorated function.
    """
    local_ns = _typing_extra.parent_frame_namespace()

    def validate(function: AnyCallableT) -> AnyCallableT:
        if isinstance(function, (classmethod, staticmethod)):
            name = type(function).__name__
            raise TypeError(f'The `@{name}` decorator should be applied after `@validate_call` (put `@{name}` on top)')

        validate_call_wrapper = _validate_call.ValidateCallWrapper(function, config, validate_return, local_ns)

        @functools.wraps(function)
        def wrapper_function(*args, **kwargs):
            return validate_call_wrapper(*args, **kwargs)

        wrapper_function.raw_function = function  # type: ignore

        return wrapper_function  # type: ignore

    if func:
        return validate(func)
    else:
        return validate