Function _accepts_n_positional_args

python/pyfory/registry.py:186–212

(factory, nargs: int)

def _accepts_n_positional_args(factory, nargs: int) -> bool:
    try:
        signature = inspect.signature(factory)
        parameters = tuple(signature.parameters.values())
    except (TypeError, ValueError):
        try:
            signature = inspect.signature(factory.__init__)
            parameters = tuple(signature.parameters.values())[1:]
        except (AttributeError, TypeError, ValueError):
            if inspect.isclass(factory) and issubclass(factory, (Serializer, CythonSerializer)):
                return nargs == 2
            raise TypeError(f"Unable to inspect serializer constructor for {factory!r}")
    min_args = 0
    max_args = 0
    has_varargs = False
    for parameter in parameters:
        if parameter.kind in (inspect.Parameter.POSITIONAL_ONLY, inspect.Parameter.POSITIONAL_OR_KEYWORD):
            max_args += 1
            if parameter.default is inspect._empty:
                min_args += 1
        elif parameter.kind == inspect.Parameter.VAR_POSITIONAL:
            has_varargs = True
    if nargs < min_args:
        return False
    if has_varargs:
        return True
    return nargs <= max_args


def _construct_serializer(serializer_factory, type_resolver, cls):