Fix action dimension check bugs (#2469)

* fix action dimension check bugs

* black codes, add test function

* clear codes for simplicity

* update check mujoco install

gym/envs/mujoco/mujoco_env.py

@@ -128,6 +128,9 @@ class MujocoEnv(gym.Env):
         return self.model.opt.timestep * self.frame_skip
 
     def do_simulation(self, ctrl, n_frames):
+        if np.array(ctrl).shape != self.action_space.shape:
+            raise ValueError("Action dimension mismatch")
+
         self.sim.data.ctrl[:] = ctrl
         for _ in range(n_frames):
             self.sim.step()

gym/envs/robotics/robot_env.py

@@ -70,6 +70,9 @@ class RobotEnv(gym.GoalEnv):
         return [seed]
 
     def step(self, action):
+        if np.array(action).shape != self.action_space.shape:
+            raise ValueError("Action dimension mismatch")
+
         action = np.clip(action, self.action_space.low, self.action_space.high)
         self._set_action(action)
         self.sim.step()

tests/envs/test_action_dim_check.py

@@ -0,0 +1,25 @@
+import pickle
+
+import pytest
+
+from gym import envs
+from tests.envs.spec_list import skip_mujoco, SKIP_MUJOCO_WARNING_MESSAGE
+
+
+ENVIRONMENT_IDS = (
+    "FetchReach-v1",
+    "HalfCheetah-v2",
+)
+
+
+@pytest.mark.skipif(skip_mujoco, reason=SKIP_MUJOCO_WARNING_MESSAGE)
+@pytest.mark.parametrize("environment_id", ENVIRONMENT_IDS)
+def test_serialize_deserialize(environment_id):
+    env = envs.make(environment_id)
+    env.reset()
+
+    with pytest.raises(ValueError, match="Action dimension mismatch"):
+        env.step([0.1])
+
+    with pytest.raises(ValueError, match="Action dimension mismatch"):
+        env.step(0.1)