Function _ensure_wrapper_signature

Lib/test/support/hashlib_helper.py:540–558

Ensure that a wrapper has the same signature as the wrapped function. This is used to guarantee that a TypeError raised due to a bad API call is raised consistently (using variadic signatures would hide such errors).

(wrapper, wrapped)

def _ensure_wrapper_signature(wrapper, wrapped):
    """Ensure that a wrapper has the same signature as the wrapped function.

    This is used to guarantee that a TypeError raised due to a bad API call
    is raised consistently (using variadic signatures would hide such errors).
    """
    try:
        wrapped_sig = inspect.signature(wrapped)
    except ValueError:  # built-in signature cannot be found
        return

    wrapper_sig = inspect.signature(wrapper)
    if wrapped_sig != wrapper_sig:
        fullname = f"{wrapped.__module__}.{wrapped.__qualname__}"
        raise AssertionError(
            f"signature for {fullname}() is incorrect:\n"
            f"  expect: {wrapped_sig}\n"
            f"  actual: {wrapper_sig}"
        )


def _make_conditional_decorator(test, /, *test_args, **test_kwargs):