[Proposal] Pyright in strict mode

[mfornet]

Proposal

I propse changing pyright to strict mode.

[tool.pyright]
typeCheckingMode = "strict"

This can be done through multiple PRs, fixing few files at a time to avoid large rewrites of the codebase.

Right now running uvx pyright in strict mode reports 604 errors.

By the way, running uvx pyright in "basic" model raise 11 errors and 3 warnings today. I guess the first step would be to correct those, and add pyright to CI.

Motivation

Right now writing for agent in env.agent_iter(): ... can't deduce the proper type of agent.

This library should be taken to a high standard, and having everything properly typed significantly improves the experience from this library users.

Pitch

Every user facing API should be properly typed for better user experience. I imagine that typing internal API can also help catching bugs and improve maintainer experience.

I imagine this proposal will be take in the spirit of "rewrite it in rust" 😅

Alternatives

This can be a daunting task, instead we can only add proper types in APIs that are consumer facing (not sure how easy are to detect those).

Additional context

No response

Checklist

• I have checked that there is no similar issue in the repo

[dm-ackerman]

I agree with this. I've done some work on this in previous PRs and I'm open to helping with this moving forward as well. Thank you for raising the issue.

[dm-ackerman]

relevant to this issue, Gymnasium has moved from pyright to ty. Farama-Foundation/Gymnasium#1383
That might be worth considering