def check_reset_seed()

in gym/utils/env_checker.py [0:0]

• 53 lines of code
• 9 McCabe index (conditional complexity)

def check_reset_seed(env: gym.Env):
    """Check that the environment can be reset with a seed.

    Args:
        env: The environment to check

    Raises:
        AssertionError: The environment cannot be reset with a random seed,
            even though `seed` or `kwargs` appear in the signature.
    """
    signature = inspect.signature(env.reset)
    if "seed" in signature.parameters or (
        "kwargs" in signature.parameters
        and signature.parameters["kwargs"].kind is inspect.Parameter.VAR_KEYWORD
    ):
        try:
            obs_1, info = env.reset(seed=123)
            assert (
                obs_1 in env.observation_space
            ), "The observation returned by `env.reset(seed=123)` is not within the observation space."
            assert (
                env.unwrapped._np_random  # pyright: ignore [reportPrivateUsage]
                is not None
            ), "Expects the random number generator to have been generated given a seed was passed to reset. Mostly likely the environment reset function does not call `super().reset(seed=seed)`."
            seed_123_rng = deepcopy(
                env.unwrapped._np_random  # pyright: ignore [reportPrivateUsage]
            )

            obs_2, info = env.reset(seed=123)
            assert (
                obs_2 in env.observation_space
            ), "The observation returned by `env.reset(seed=123)` is not within the observation space."
            if env.spec is not None and env.spec.nondeterministic is False:
                assert data_equivalence(
                    obs_1, obs_2
                ), "Using `env.reset(seed=123)` is non-deterministic as the observations are not equivalent."
            assert (
                env.unwrapped._np_random.bit_generator.state  # pyright: ignore [reportPrivateUsage]
                == seed_123_rng.bit_generator.state
            ), "Mostly likely the environment reset function does not call `super().reset(seed=seed)` as the random generates are not same when the same seeds are passed to `env.reset`."

            obs_3, info = env.reset(seed=456)
            assert (
                obs_3 in env.observation_space
            ), "The observation returned by `env.reset(seed=456)` is not within the observation space."
            assert (
                env.unwrapped._np_random.bit_generator.state  # pyright: ignore [reportPrivateUsage]
                != seed_123_rng.bit_generator.state
            ), "Mostly likely the environment reset function does not call `super().reset(seed=seed)` as the random number generators are not different when different seeds are passed to `env.reset`."

        except TypeError as e:
            raise AssertionError(
                "The environment cannot be reset with a random seed, even though `seed` or `kwargs` appear in the signature. "
                f"This should never happen, please report this issue. The error was: {e}"
            )

        seed_param = signature.parameters.get("seed")
        # Check the default value is None
        if seed_param is not None and seed_param.default is not None:
            logger.warn(
                "The default seed argument in reset should be `None`, otherwise the environment will by default always be deterministic. "
                f"Actual default: {seed_param.default}"
            )
    else:
        raise gym.error.Error(
            "The `reset` method does not provide a `seed` or `**kwargs` keyword argument."
        )