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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
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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/2.7/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.
    """

    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)

        @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