15. Tooling, Quality, and Packaging

Centralize configs in pyproject.toml, enforce quality pre-commit, and build reproducible artifacts.

Q1 What is the role of pyproject.toml in a modern Python project?

Answer: pyproject.toml (defined in PEP 518) is a standardized configuration file that centralizes the configuration for build tools, formatters, linters, and type checkers. It replaces the need for multiple separate config files (like setup.py, requirements.txt, .black.toml), creating a single source of truth for project metadata and tooling.

Explanation: Tools like ruff, black, mypy, and pytest can all be configured within the [tool.*] sections of pyproject.toml. This simplifies project setup and ensures consistency.

[tool.ruff]
line-length = 100
target-version = "py311"

[tool.mypy]
python_version = "3.11"
strict = true

Q2 How do you enforce code quality pre-commit?

Answer: Use pre-commit to run ruff, black, mypy, and tests on staged changes.

Explanation: Prevents bad code from entering the repo.

# .pre-commit-config.yaml
- repo: https://github.com/astral-sh/ruff-pre-commit
  rev: v0.6.8
  hooks: [ { id: ruff }, { id: ruff-format } ]