Fix typehint and address the mypy errors of src/lerobot/configs

[tetsugo02]

Added type hint and ensure the lerobot/configs modules pass the mypy check

Fixes #1730

Changes

In this pr, I mainly fixed the mypy error, so I test my changes by using mypy and pre-commit
I changed pyproject.toml and .pre-commit-config as follows.

[tool.mypy]
python_version = "3.10"
ignore_missing_imports = true
follow_imports = "skip"

[[tool.mypy.overrides]]
module = "lerobot.configs.*"
ignore_errors = false

# extra strictness for configs
disallow_untyped_defs = true
disallow_incomplete_defs = true
check_untyped_defs = true

# ignores
disable_error_code = ["attr-defined"] #TODO: draccus issue

# include = "src/lerobot/configs/**/*.py"

How it was tested

pre-commit

In this pr, I mainly fixed the mypy error, you can test the changes by using:

pre-commit run --all-files

mypy

mypy  src/lerobot/configs/ 

Added type: ignore

• src/lerobot/configs/train:
  • Used third-party library uses Any as return type
• src/lerobot/configs/train
  • The parent class TrainPipelineConfig defined the dataset' type as DatasetConfig. And this property is used in many places. It was difficult to change.
• src/lerobot/configs/policies
  • The parent class having a same name method makes here error, but the push_to_hub is also used in many places.
• https://github.com/tetsugo02/lerobot/blob/8fcbed4d7653532c19b451af2ff6c279368eb194/src/lerobot/configs/policies.py#L98-L109
  • No implementation
• https://github.com/tetsugo02/lerobot/blob/8fcbed4d7653532c19b451af2ff6c279368eb194/src/lerobot/configs/policies.py#L40
  • draccus issue

[Copilot]

Pull Request Overview

This PR fixes type hint issues and addresses mypy errors in the src/lerobot/configs module to ensure the codebase passes mypy static type checking.

• Adds proper type annotations to function return types and variables
• Fixes mypy errors related to assignment and type mismatches
• Improves error handling by raising exceptions instead of printing messages
• Adds null checks and proper handling for optional parameters

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/lerobot/configs/train.py	Adds type hints, improves validation logic with null checks, and fixes assignment issues
src/lerobot/configs/policies.py	Adds type annotations and converts print statement to proper exception raising
src/lerobot/configs/parser.py	Adds return type annotations and null safety checks for argument filtering
src/lerobot/configs/eval.py	Adds null safety checks for policy attribute access

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[tetsugo02]

Hello,
I am new to OSS, and this is my first attempt at contributing to this project.
I would appreciate any feedback. Thanks.

[AdilZouitine]

LGTM, I'm waiting the review of one more team member to approve and precommit hook pass!
Thanks for the contribution!

[AdilZouitine]

@tetsugo02 we change how to integrate step by step typing in the codebase.
We will merge right away if the ci is green.

[AdilZouitine]

Very nice @tetsugo02, we started to merge some pr related to typing, to make the transition smoother we change some stuff in pyproject. I rebase your branch could you handle the conflict and make it runs. Then we directly merge! Thank you for your contribution 😄

[tetsugo02]

@AdilZouitine
I have resovled conflict and merged main into my branch! Because I am not fammiliar with pre-commit, if I did anything strange, please tell me that I can fix it.