Function getfuncargnames

src/_pytest/compat.py:119–186

Return the names of a function's mandatory arguments. Should return the names of all function arguments that: * Aren't bound to an instance or type as in instance or class methods. * Don't have default values. * Aren't bound with functools.partial. * Aren't replaced with mocks.

(
    function: Callable[..., Any],
    *,
    name: str = "",
    is_method: bool = False,
    cls: Optional[type] = None,
)

def getfuncargnames(
    function: Callable[..., Any],
    *,
    name: str = "",
    is_method: bool = False,
    cls: Optional[type] = None,
) -> Tuple[str, ...]:
    """Return the names of a function's mandatory arguments.

    Should return the names of all function arguments that:
    * Aren't bound to an instance or type as in instance or class methods.
    * Don't have default values.
    * Aren't bound with functools.partial.
    * Aren't replaced with mocks.

    The is_method and cls arguments indicate that the function should
    be treated as a bound method even though it's not unless, only in
    the case of cls, the function is a static method.

    The name parameter should be the original name in which the function was collected.
    """
    # TODO(RonnyPfannschmidt): This function should be refactored when we
    # revisit fixtures. The fixture mechanism should ask the node for
    # the fixture names, and not try to obtain directly from the
    # function object well after collection has occurred.

    # The parameters attribute of a Signature object contains an
    # ordered mapping of parameter names to Parameter instances.  This
    # creates a tuple of the names of the parameters that don't have
    # defaults.
    try:
        parameters = signature(function).parameters
    except (ValueError, TypeError) as e:
        from _pytest.outcomes import fail

        fail(
            f"Could not determine arguments of {function!r}: {e}",
            pytrace=False,
        )

    arg_names = tuple(
        p.name
        for p in parameters.values()
        if (
            p.kind is Parameter.POSITIONAL_OR_KEYWORD
            or p.kind is Parameter.KEYWORD_ONLY
        )
        and p.default is Parameter.empty
    )
    if not name:
        name = function.__name__

    # If this function should be treated as a bound method even though
    # it's passed as an unbound method or function, remove the first
    # parameter name.
    if is_method or (
        # Not using `getattr` because we don't want to resolve the staticmethod.
        # Not using `cls.__dict__` because we want to check the entire MRO.