Function _fixture_cache

python/tvm/testing/utils.py:1022–1091

(func)

def _fixture_cache(func):
    cache = {}

    # Can't use += on a bound method's property.  Therefore, this is a
    # list rather than a variable so that it can be accessed from the
    # pytest_collection_modifyitems().
    num_tests_use_this_fixture = [0]

    num_times_fixture_used = 0

    # Using functools.lru_cache would require the function arguments
    # to be hashable, which wouldn't allow caching fixtures that
    # depend on numpy arrays.  For example, a fixture that takes a
    # numpy array as input, then calculates uses a slow method to
    # compute a known correct output for that input.  Therefore,
    # including a fallback for serializable types.
    def get_cache_key(*args, **kwargs):
        try:
            hash((args, kwargs))
            return (args, kwargs)
        except TypeError:
            pass

        try:
            return pickle.dumps((args, kwargs))
        except TypeError as e:
            raise TypeError(
                "TVM caching of fixtures requires arguments to the fixture "
                "to be either hashable or serializable"
            ) from e

    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        if num_tests_use_this_fixture[0] == 0:
            raise RuntimeError(
                "Fixture use count is 0.  "
                "This can occur if tvm.testing.plugin isn't registered.  "
                "If using outside of the TVM test directory, "
                "please add `pytest_plugins = ['tvm.testing.plugin']` to your conftest.py"
            )

        try:
            cache_key = get_cache_key(*args, **kwargs)

            try:
                cached_value = cache[cache_key]
            except KeyError:
                cached_value = cache[cache_key] = func(*args, **kwargs)

            yield copy.deepcopy(
                cached_value,
                # allowed_class_list should be a list of classes that
                # are safe to copy using copy.deepcopy, but do not
                # implement __deepcopy__, __reduce__, or
                # __reduce_ex__.
                _DeepCopyAllowedClasses(allowed_class_list=[]),
            )