Bug with `concat_vec_envs_v1` when `num_cpus` and `num_vec_envs` > 1

[inCloudRain]

When min(num_cpus, num_vec_envs) > 1, the call to MakeCPUAsyncConstructor(num_cpus) (in vector_constructors.py:64) returns a constructor function that requires obs_space and act_space as arguments, but vec_env_args(vec_env, num_vec_envs) does not provide these required arguments.

[pseudo-rnd-thoughts]

Hey, could you provide some code to help debug this?

[inCloudRain]

Sure. For example, consider the following code:

from mpe2 import simple_spread_v3
import supersuit as ss

env = simple_spread_v3.parallel_env()
env = ss.pettingzoo_env_to_vec_env_v1(env)
env = ss.concat_vec_envs_v1(env, 10, num_cpus=10, base_class="gymnasium")
obs, info = env.reset()

env.close()

When num_cpus is set to 1, the code runs without issues. However, if num_cpus is greater than 1, the following error occurs:

Traceback (most recent call last):
  File "test.py", line 6, in <module>
    env = ss.concat_vec_envs_v1(env, 10, num_cpus=10, base_class="gymnasium")
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".../Lib/site-packages/supersuit/vector/vector_constructors.py", line 64, in concat_vec_envs_v1
    vec_env = MakeCPUAsyncConstructor(num_cpus)(*vec_env_args(vec_env, num_vec_envs))
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: MakeCPUAsyncConstructor.<locals>.constructor() missing 2 required positional arguments: 'obs_space' and 'act_space'

[pseudo-rnd-thoughts]

Looks like someone already made a PR to fix it - #258

[dm-ackerman]

Looks like someone already made a PR to fix it - #258

@pseudo-rnd-thoughts Any chance you're able to merge that PR? Or, if not, do you know who can?