[BugFix] Format the key and class name into two error messages

test/objectives/test_cql.py

@@ -1063,6 +1063,14 @@ def test_dcql_tensordict_run(self, action_spec_type, td_est):
             _ = loss_fn(td)
         assert loss_fn.tensor_keys.priority in td.keys()
 
+    def test_dcql_cql_loss_before_value_loss(self):
+        actor = self._create_mock_actor(action_spec_type="one_hot")
+        loss_fn = DiscreteCQLLoss(actor)
+        loss_fn.set_keys(pred_val="custom_pred_val")
+        td = self._create_mock_data_dcql(action_spec_type="one_hot")
+        with pytest.raises(KeyError, match="with key custom_pred_val in"):
+            loss_fn.cql_loss(td)
+
     @pytest.mark.parametrize("observation_key", ["observation", "observation2"])
     @pytest.mark.parametrize("reward_key", ["reward", "reward2"])
     @pytest.mark.parametrize("done_key", ["done", "done2"])

torchrl/envs/batched_envs.py

@@ -3213,7 +3213,7 @@ def _shutdown_workers(self) -> None:
         try:
             if self.is_closed:
                 raise RuntimeError(
-                    "calling {self.__class__.__name__}._shutdown_workers only allowed when env.is_closed = False"
+                    f"calling {self.__class__.__name__}._shutdown_workers only allowed when env.is_closed = False"
                 )
             if self._metadata_from_workers:
                 # Expensive native environments may retain renderer resources

torchrl/objectives/cql.py

@@ -1337,7 +1337,7 @@ def cql_loss(self, tensordict):
         qvalues = tensordict.get(self.tensor_keys.pred_val, default=None)
         if qvalues is None:
             raise KeyError(
-                "Couldn't find the predicted qvalue with key {self.tensor_keys.pred_val} in the input tensordict. "
+                f"Couldn't find the predicted qvalue with key {self.tensor_keys.pred_val} in the input tensordict. "
                 "This could be caused by calling cql_loss method before value_loss."
             )