Method get

python/tvm/testing/utils.py:975–1019

Overrides behavior of copy.deepcopy to avoid implicit copy. By default, copy.deepcopy uses a dict of id->object to track all objects that it has seen, which is passed as the second argument to all recursive calls. This class is intended to be passed in instead, and

(self, key, *args, **kwargs)

        super().__init__()

    def get(self, key, *args, **kwargs):
        """Overrides behavior of copy.deepcopy to avoid implicit copy.

        By default, copy.deepcopy uses a dict of id->object to track
        all objects that it has seen, which is passed as the second
        argument to all recursive calls.  This class is intended to be
        passed in instead, and inspects the type of all objects being
        copied.

        Where copy.deepcopy does a best-effort attempt at copying an
        object, for unit tests we would rather have all objects either
        be copied correctly, or to throw an error.  Classes that
        define an explicit method to perform a copy are allowed, as
        are any explicitly listed classes.  Classes that would fall
        back to using object.__reduce__, and are not explicitly listed
        as safe, will throw an exception.

        """
        obj = ctypes.cast(key, ctypes.py_object).value
        cls = type(obj)
        if (
            cls in copy._deepcopy_dispatch
            or issubclass(cls, type)
            or getattr(obj, "__deepcopy__", None)
            or copyreg.dispatch_table.get(cls)
            or cls.__reduce__ is not object.__reduce__
            or cls.__reduce_ex__ is not object.__reduce_ex__
            or cls in self.allowed_class_list
        ):
            return super().get(key, *args, **kwargs)

        rfc_url = (
            "https://github.com/apache/tvm-rfcs/blob/main/rfcs/0007-parametrized-unit-tests.md"
        )
        raise TypeError(
            f"Cannot copy fixture of type {cls.__name__}.  TVM fixture caching "
            "is limited to objects that explicitly provide the ability "
            "to be copied (e.g. through __deepcopy__, __getstate__, or __setstate__),"
            "and forbids the use of the default `object.__reduce__` and "
            "`object.__reduce_ex__`.  For third-party classes that are "
            "safe to use with copy.deepcopy, please add the class to "
            "the arguments of _DeepCopyAllowedClasses in tvm.testing._fixture_cache.\n"
            "\n"
            f"For discussion on this restriction, please see {rfc_url}."
        )


def _fixture_cache(func):