Fixing missing number of steps check (Farama-Foundation#435)

metaworld/envs/mujoco/sawyer_xyz/sawyer_xyz_env.py

@@ -459,6 +459,10 @@ def step(self, action):
         assert len(action) == 4, f"Actions should be size 4, got {len(action)}"
         self.set_xyz_action(action[:3])
         self.do_simulation([action[-1], -action[-1]], n_frames=self.frame_skip)
+        if self.curr_path_length > self.max_path_length:
+            raise ValueError(
+                "Maximum path length allowed by the benchmark has been exceeded"
+            )
         self.curr_path_length += 1
 
         # Running the simulator can sometimes mess up site positions, so
@@ -470,6 +474,7 @@ def step(self, action):
             return (
                 self._last_stable_obs,  # observation just before going unstable
                 0.0,  # reward (penalize for causing instability)
+                False,
                 False,  # termination flag always False
                 {  # info
                     "success": False,