flake8でPythonコードを静的チェックする（Lint）
flake8はLintツール。いわゆるコードの静的チェッカー。
情報源
Flake8
Lintツール。Pythonのソースコードを静的チェックする。
- PEP8によるコードの静的チェック
- pyflakesによる論理エラーチェック
- 循環的複雑度をチェック
インストール
pip3 install flake8
使ってみる
コードを用意する
a.py
#!/usr/bin/env python3 # coding: utf8 def my_Method(p): print('Hello Python!!') if __name__ == '__main__': my_Method('value')
チェックする
flake8 a.py
問題点が出た。
a.py:5:1: E305 expected 2 blank lines after class or function definition, found 0 a.py:7:1: W391 blank line at end of file
チッ、英語かよ。しかもぜんぶ改行関係。べつにそのくらいいいじゃん。心の狭い表れですな。
ていうか、メソッド名に大文字が入っちゃってんですけど。アウトでしょこれ。ダメだ、ぜんぜんチェックしてくれてないやん。
コードも表示する
flake8 --show-source .
./a.py:5:1: E305 expected 2 blank lines after class or function definition, found 0 if __name__ == '__main__': ^ ./a.py:7:1: W391 blank line at end of file ^
とにかく、こんな感じでチェックしてくれる。
こいつを手作業で修正してもいいのだが、自動的に修正してくれるツールがある。次回紹介する。
ヘルプ
flake8 --help
usage: flake8 [options] file file ... positional arguments: filename optional arguments: -h, --help show this help message and exit -v, --verbose Print more information about what is happening in flake8. This option is repeatable and will increase verbosity each time it is repeated. --output-file OUTPUT_FILE Redirect report to a file. --append-config APPEND_CONFIG Provide extra config files to parse in addition to the files found by Flake8 by default. These files are the last ones read and so they take the highest precedence when multiple files provide the same option. --config CONFIG Path to the config file that will be the authoritative config source. This will cause Flake8 to ignore all other configuration files. --isolated Ignore all configuration files. --version show program's version number and exit -q, --quiet Report only file names, or nothing. This option is repeatable. --count Print total number of errors and warnings to standard error and set the exit code to 1 if total is not empty. --diff Report changes only within line number ranges in the unified diff provided on standard in by the user. --exclude patterns Comma-separated list of files or directories to exclude. (Default: ['.svn', 'CVS', '.bzr', '.hg', '.git', '__pycache__', '.tox', '.eggs', '*.egg']) --extend-exclude patterns Comma-separated list of files or directories to add to the list of excluded ones. --filename patterns Only check for filenames matching the patterns in this comma-separated list. (Default: ['*.py']) --stdin-display-name STDIN_DISPLAY_NAME The name used when reporting errors from code passed via stdin. This is useful for editors piping the file contents to flake8. (Default: stdin) --format format Format errors according to the chosen formatter. --hang-closing Hang closing bracket instead of matching indentation of opening bracket's line. --ignore errors Comma-separated list of errors and warnings to ignore (or skip). For example, ``--ignore=E4,E51,W234``. (Default: ['E704', 'E126', 'E226', 'E123', 'W503', 'E121', 'E24', 'W504']) --extend-ignore errors Comma-separated list of errors and warnings to add to the list of ignored ones. For example, ``--extend- ignore=E4,E51,W234``. --per-file-ignores PER_FILE_IGNORES A pairing of filenames and violation codes that defines which violations to ignore in a particular file. The filenames can be specified in a manner similar to the ``--exclude`` option and the violations work similarly to the ``--ignore`` and ``--select`` options. --max-line-length n Maximum allowed line length for the entirety of this run. (Default: 79) --max-doc-length n Maximum allowed doc line length for the entirety of this run. (Default: None) --indent-size n Number of spaces used for indentation (Default: 4) --select errors Comma-separated list of errors and warnings to enable. For example, ``--select=E4,E51,W234``. (Default: ['E', 'F', 'W', 'C90']) --extend-select errors Comma-separated list of errors and warnings to add to the list of selected ones. For example, ``--extend- select=E4,E51,W234``. --disable-noqa Disable the effect of "# noqa". This will report errors on lines with "# noqa" at the end. --show-source Show the source generate each error or warning. --no-show-source Negate --show-source --statistics Count errors and warnings. --enable-extensions ENABLE_EXTENSIONS Enable plugins and extensions that are otherwise disabled by default --exit-zero Exit with status code "0" even if there are errors. -j JOBS, --jobs JOBS Number of subprocesses to use to run checks in parallel. This is ignored on Windows. The default, "auto", will auto-detect the number of processors available to use. (Default: auto) --tee Write to stdout and output-file. --benchmark Print benchmark information about this run of Flake8 --bug-report Print information necessary when preparing a bug report mccabe: --max-complexity MAX_COMPLEXITY McCabe complexity threshold pyflakes: --builtins BUILTINS define more built-ins, comma separated --doctests also check syntax of the doctests --include-in-doctest INCLUDE_IN_DOCTEST Run doctests only on these files --exclude-from-doctest EXCLUDE_FROM_DOCTEST Skip these files when running doctests Installed plugins: mccabe: 0.6.1, pycodestyle: 2.8.0, pyflakes: 2.4.0
対象環境
- Raspbierry pi 4 Model B
- Raspberry Pi OS buster 10.0 2020-08-20 ※
- bash 5.0.3(1)-release
$ uname -a Linux raspberrypi 5.10.52-v7l+ #1441 SMP Tue Aug 3 18:11:56 BST 2021 armv7l GNU/Linux
