Add error message when terminating the MuJoCo renderer without calling env.close

[a-ayesh]

Description

A detailed comment is provided in my name under the issue referenced.

The change summary is:

• Added AttributeError exception handling to the free() method in mujoco_rendering.py.
• Gracefully handles freeing the OpenGL context and closing the GLFW window in the event that the user does not call env.close() before the program terminates when they've set render_mode: 'human'.
• Added docstring for the free() method.

Fixes #1224

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[pseudo-rnd-thoughts]

Thanks for the PR, I think this will resolve the issue for users.
Could you change the print to a gymnasium.logger.warn
Also could you run pre-commit run --all-files

Otherwise good to me, @Kallinteris-Andreas any thoughts?

[Kallinteris-Andreas]

It works, tested with:

import gymnasium

env = gymnasium.make('Humanoid-v5', render_mode='human')
obs, info = env.reset()
#env.close()

Also, please run pre-commit --all-files (more info on contributing.md)

[a-ayesh]

Could you change the print to a gymnasium.logger.warn

I changed the print statement to use warn. The error now looks like:

/home/user/Gymnasium/gymnasium/envs/mujoco/mujoco_rendering.py:372: UserWarning: WARN: Environment was not properly closed using 'env.close()'. Please ensure to close the environment explicitly. GLFW module or dependencies are unloaded. Window cleanup might not have completed.

Also could you run pre-commit run --all-files

Also I apologize for marking that I ran pre-commit run --all-files. I am actually struggling to run it? I get stuck at

An unexpected error has occurred: CalledProcessError: command: ('/home/cowlar/.cache/pre-commit/repoiipfy4zl/node_env-system/bin/node', '/usr/local/bin/npm', 'install', '--include=dev', '--include=prod', '--ignore-prepublish', '--no-progress', '--no-save')
return code: 1
stdout: (none)
stderr:
    internal/modules/cjs/loader.js:638
        throw err;
        ^
    
    Error: Cannot find module 'node:path'
        at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
        at Function.Module._load (internal/modules/cjs/loader.js:562:25)
        at Module.require (internal/modules/cjs/loader.js:692:17)
        at require (internal/modules/cjs/helpers.js:25:18)
        at Object.<anonymous> (/usr/local/lib/node_modules/npm/lib/cli.js:10:18)
        at Module._compile (internal/modules/cjs/loader.js:778:30)
        at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
        at Module.load (internal/modules/cjs/loader.js:653:32)
        at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
        at Function.Module._load (internal/modules/cjs/loader.js:585:3)
Check the log at /home/cowlar/.cache/pre-commit/pre-commit.log

I am using my work PC though, so I don't want to mess up anything just in case. It would be nice if either of you could checkout the branch from my fork to run it, otherwise I might do it in a day or two.

[Kallinteris-Andreas]

You can use GitHub Codespaces on your branch to easily run pre-commit.
Or use pipx locally

[a-ayesh]

Hi, I apologize for a simple change request taking so long. I've run the pre-commit run --all-files and implemented requested changes. Please give it a final review @Kallinteris-Andreas and @pseudo-rnd-thoughts.

[Kallinteris-Andreas]

No worries, Thanks for the pull request.

[BasharSiddiqui]

Great job @a-ayesh !