Ruffで快適なPython環境を構築する

select = ["N", "E", "W", "D", "F", "I", "C90", "S"]

[lint.mccabe]
max-complexity = 3

# main.py
import os, sys
import io


def tooBadFunction(a, b, c):
    """ダメな関数のdocstring"""
    eval(sys.argv[1])
    if a:
        if b:
            if c:
                return 1
            else:
                return 2
        else:
            return 3
        return 4

$ ruff main.py
warning: `one-blank-line-before-class` (D203) and `no-blank-line-before-class` (D211) are incompatible. Ignoring `one-blank-line-before-class`.
warning: `multi-line-summary-first-line` (D212) and `multi-line-summary-second-line` (D213) are incompatible. Ignoring `multi-line-summary-second-line`.
main.py:1:1: E401 Multiple imports on one line
main.py:1:1: D100 Missing docstring in public module
main.py:1:1: I001 [*] Import block is un-sorted or un-formatted
main.py:1:8: F401 [*] `os` imported but unused
main.py:2:8: F401 [*] `io` imported but unused
main.py:5:5: N802 Function name `tooBadFunction` should be lowercase
main.py:5:5: C901 `tooBadFunction` is too complex (4 > 3)
main.py:6:5: D202 [*] No blank lines allowed after function docstring (found 1)
main.py:6:5: D400 First line should end with a period
main.py:6:5: D415 First line should end with a period, question mark, or exclamation point
main.py:8:5: S307 Use of possibly insecure function; consider using `ast.literal_eval`
Found 11 errors.
[*] 4 fixable with the `--fix` option (2 hidden fixes can be enabled with the `--unsafe-fixes` option).

select =  ["N", "E", "W", "D", "F", "I", "C90", "S"]
ignore = ["D203", "D212", "D400", "D415"]

[lint.mccabe]
max-complexity = 3

select =  ["N", "E", "W", "D", "F", "I", "C90", "S"]
ignore = ["D415"]

[lint.pydocstyle]
convention = "google"

[lint.mccabe]
max-complexity = 3

$ ruff main.py
# 単一行での複数インポート
main.py:1:1: E401 Multiple imports on one line
# モジュールレベルのdocstringが記述されていない
main.py:1:1: D100 Missing docstring in public module
# インポートブロックがソートされていない
main.py:1:1: I001 [*] Import block is un-sorted or un-formatted
# 未使用インポート
main.py:1:8: F401 [*] `os` imported but unused
main.py:2:8: F401 [*] `io` imported but unused
# 関数名がキャメルケース（PEP8だとPythonはスネークケース）
main.py:5:5: N802 Function name `tooBadFunction` should be lowercase
# 複雑度が閾値（3）を超えている
main.py:5:5: C901 `tooBadFunction` is too complex (4 > 3)
# docstringの後は空行を入れる（PEP257）
main.py:6:5: D202 [*] No blank lines allowed after function docstring (found 1)
# evalはセキュリティ的にNG
main.py:8:5: S307 Use of possibly insecure function; consider using `ast.literal_eval`
Found 9 errors.
[*] 4 fixable with the `--fix` option..

# .vscode/settings.json
{
    "[python]": {
        "editor.defaultFormatter": "charliermarsh.ruff",
        "editor.codeActionsOnSave": {
            "source.fixAll.ruff": "always",
            "source.organizeImports.ruff": "always"
        },
        "editor.formatOnSave": true,
    },
}