Fix pyright type errors

[benjibc]

---

name: Pull Request
about: Propose changes to the codebase
title: "Fix: Resolve Pyright type errors in reward modules"
labels: ''
assignees: ''

---

Description

This PR addresses a batch of Pyright type errors, primarily related to the Message.content field, which can be either a str or a list of content parts.

A new utility module, eval_protocol/rewards/_content_utils.py, has been introduced with to_text and to_text_any helpers. These functions normalize Message.content into a plain string, preventing type checker errors when string operations are performed.

These helpers have been integrated across various reward modules, including accuracy.py, apps_coding_reward.py, json_schema.py, language_consistency.py, length.py, list_comparison_math_reward.py, math.py, multiple_choice_math_reward.py, reasoning_steps.py, and tag_count.py.

Additionally, specific type issues such as unbound variables in apps_coding_reward.py, list type invariance in math.py, and import/call signature issues in json_schema.py have been resolved.

This change resolves approximately 30+ type errors, improving the codebase's type safety and maintainability.

Fixes # (issue)
Implements # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality) - New utility module
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Refactoring/Code cleanup
• Build/CI/CD related changes
• Other (please describe):

How Has This Been Tested?

The changes were verified by running the basedpyright type checker locally before and after the modifications.
Spot checks confirmed zero errors in accuracy.py, language_consistency.py, tag_count.py, reasoning_steps.py, multiple_choice_math_reward.py, apps_coding_reward.py, length.py, and math.py.

Test Configuration:

• Toolchain: basedpyright (via pre-commit hook)

Checklist:

• My code follows the style guidelines of this project (ran black ., isort ., flake8 .)
• I have performed a self-review of my own code
• 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
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

Screenshots (if applicable)

Additional context

This PR addresses the first batch of Pyright errors as requested. Remaining errors, largely related to missing optional dependencies and other modules, can be tackled in subsequent PRs.

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