Python Build Tools

Python Build Tools

Modern Python development tooling using uv, mise, Ruff, basedpyright, and pytest. Target Python 3.12-3.14 and stable tool releases.

Quick Start

Minimal pyproject.toml

[project]
name = "my-project"
version = "0.1.0"
requires-python = ">=3.12"
dependencies = ["fastapi", "pydantic"]

[dependency-groups]
dev = ["pytest", "pytest-cov", "ruff", "basedpyright"]

[build-system]
requires = ["hatchling>=1.27,<2"]
build-backend = "hatchling.build"

[tool.ruff]
target-version = "py312"

[tool.ruff.lint]
select = ["E", "F", "I", "N", "UP", "RUF"]

[tool.basedpyright]
typeCheckingMode = "strict"

[tool.pytest.ini_options]
testpaths = ["tests"]

Setup Project

uv init my-project && cd my-project
uv sync
uv add fastapi pydantic
uv add --dev pytest pytest-cov ruff basedpyright

Tool Overview

Common Commands

Lint and Format

uv run ruff check .
uv run ruff format --check .

# Apply changes locally, never in CI.
uv run ruff check --fix .
uv run ruff format .

Type Check

uv run basedpyright
uv run basedpyright src/main.py

Test

uv run pytest
uv run pytest --cov=src --cov-report=html

Manage Dependencies

uv add fastapi
uv add --dev pytest
uv lock --upgrade
uv tree

Mise Configuration

Create .mise.toml for consistent development:

[tools]
python = "3.14"

[tasks.lint]
run = "uv run ruff check ."

[tasks.format]
run = "uv run ruff format --check ."

[tasks.typecheck]
run = "uv run basedpyright"

[tasks.test]
run = "uv run pytest"

[tasks.check]
depends = ["lint", "format", "typecheck", "test"]

Usage:

mise install
mise run check

Type Hints Example

from decimal import Decimal
from typing import Optional

def calculate_discount(
    total: Decimal,
    rate: Optional[Decimal] = None
) -> Decimal:
    if rate is None:
        rate = Decimal("0.1")
    return total * rate

Best Practices

1. Commit uv.lock and use uv sync --locked in CI.
2. Pin tool versions in CI or through tool.uv.required-version; refresh deliberately.
3. Declare compatible dependency ranges in metadata and use the lockfile for selected versions.
4. Separate non-mutating checks from local auto-fixes.
5. Use optional dependencies only for published user-selectable features, not development tools.

References

For detailed configuration and advanced patterns:

• references/uv.md - Dependency groups, locks, indexes, builds, and publishing
• references/ruff.md - Rules, per-file ignores, pre-commit integration
• references/basedpyright.md - Type patterns, generics, protocols