Allow env_kwargs in make_vec_env when env ID string supplied (#189)

* Allow env_kwargs in make_vec_env when env ID string supplied

Resolves #188

* Update docs/misc/changelog.rst

Co-authored-by: Antonin RAFFIN <antonin.raffin@ensta.org>

* Add test for env kargs in make_vec_env

* remove unnecessary args in test_vec_env_kwargs function

* Fixes and reformat

* Doc fix

Co-authored-by: Antonin RAFFIN <antonin.raffin@ensta.org>

.gitignore

@@ -6,6 +6,7 @@
 .pytest_cache
 .DS_Store
 .idea
+.vscode
 .coverage
 .coverage.*
 __pycache__/

docs/misc/changelog.rst

@@ -17,6 +17,7 @@ New Features:
 Bug Fixes:
 ^^^^^^^^^^
 - Fix GAE computation for on-policy algorithms (off-by one for the last value) (thanks @Wovchena)
+- Make ``make_vec_env`` support the ``env_kwargs`` argument when using an env ID str (@ManifoldFR)
 
 Deprecations:
 ^^^^^^^^^^^^^
@@ -25,6 +26,7 @@ Others:
 ^^^^^^^
 - Improved typing coverage
 - Improved error messages for unsupported spaces
+- Added ``.vscode`` to the gitignore
 
 Documentation:
 ^^^^^^^^^^^^^^

stable_baselines3/common/cmd_util.py

@@ -1,5 +1,4 @@
 import os
-import warnings
 from typing import Any, Callable, Dict, Optional, Type, Union
 
 import gym
@@ -45,9 +44,7 @@ def make_vec_env(
     def make_env(rank):
         def _init():
             if isinstance(env_id, str):
-                env = gym.make(env_id)
-                if len(env_kwargs) > 0:
-                    warnings.warn("No environment class was passed (only an env ID) so ``env_kwargs`` will be ignored")
+                env = gym.make(env_id, **env_kwargs)
             else:
                 env = env_id(**env_kwargs)
             if seed is not None:

tests/test_utils.py

@@ -65,6 +65,11 @@ def test_make_atari_env(env_id, n_envs, wrapper_kwargs):
         assert np.max(np.abs(reward)) < 1.0
 
 
+def test_vec_env_kwargs():
+    env = make_vec_env("MountainCarContinuous-v0", n_envs=1, seed=0, env_kwargs={"goal_velocity": 0.11})
+    assert env.get_attr("goal_velocity")[0] == 0.11
+
+
 def test_custom_vec_env(tmp_path):
     """
     Stand alone test for a special case (passing a custom VecEnv class) to avoid doubling the number of tests.