black

black documentation

Version in Mega-Linter: 21.9
Visit Official Web Site
See How to configure black rules
- If custom .python-black config file is not found, .python-black will be used

Configuration in Mega-Linter

Enable black by adding PYTHON_BLACK in ENABLE_LINTERS variable
Disable black by adding PYTHON_BLACK in DISABLE_LINTERS variable

Enable auto-fixes by adding PYTHON_BLACK in APPLY_FIXES variable

Variable	Description	Default value
PYTHON_BLACK_ARGUMENTS	User custom arguments to add in linter CLI call Ex: `-s --foo "bar"`
PYTHON_BLACK_FILTER_REGEX_INCLUDE	Custom regex including filter Ex: `(src\\|lib)`	Include every file
PYTHON_BLACK_FILTER_REGEX_EXCLUDE	Custom regex excluding filter Ex: `(test\\|examples)`	Exclude no file
PYTHON_BLACK_CLI_LINT_MODE	Override default CLI lint mode - `file`: Calls the linter for each file - `list_of_files`: Call the linter with the list of files as argument - `project`: Call the linter from the root of the project	`{linter.cli_lint_mode}`
PYTHON_BLACK_FILE_EXTENSIONS	Allowed file extensions. `"*"` matches any extension, `""` matches empty extension. Empty list excludes all files Ex: `[".py", ""]`	`[".py"]`
PYTHON_BLACK_FILE_NAMES_REGEX	File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files Ex: `["Dockerfile(-.+)?", "Jenkinsfile"]`	Include every file
PYTHON_BLACK_PRE_COMMANDS	List of bash commands to run before the linter	None
PYTHON_BLACK_POST_COMMANDS	List of bash commands to run after the linter	None
PYTHON_BLACK_CONFIG_FILE	black configuration file name Use `LINTER_DEFAULT` to let the linter find it	`.python-black`
PYTHON_BLACK_RULES_PATH	Path where to find linter configuration file	Workspace folder, then Mega-Linter default rules
PYTHON_BLACK_DISABLE_ERRORS	Run linter but consider errors as warnings	`true`
PYTHON_BLACK_DISABLE_ERRORS_IF_LESS_THAN	Maximum number of errors allowed	`0`

IDE Integration

Use black in your favorite IDE to catch errors before Mega-Linter !

IDE	Extension Name	Install
Atom	python-black	Visit Web Site
Emacs	blacken	Visit Web Site
Emacs	reformatter.el	Visit Web Site
Emacs	elpy	Visit Web Site
IDEA	black	Visit Web Site
Sublime Text	sublack	Visit Web Site
Visual Studio Code	VsCode Python Extension

Mega-Linter Flavours

This linter is available in the following flavours

	Flavor	Description	Embedded linters	Info
	all	Default Mega-Linter Flavor	93
	python	Optimized for PYTHON based projects	48

Behind the scenes

How are identified applicable files

File extensions: .py

How the linting is performed

black is called once with the list of files as arguments

Example calls

black --diff --check myfile.py

black --config .python-black --diff --check myfile.py

black --config .python-black myfile.py

Help content

Usage: black [OPTIONS] SRC ...

  The uncompromising code formatter.

Options:
  -c, --code TEXT                 Format the code passed in as a string.
  -l, --line-length INTEGER       How many characters per line to allow.
                                  [default: 88]

  -t, --target-version [py27|py33|py34|py35|py36|py37|py38|py39]
                                  Python versions that should be supported by
                                  Black's output. [default: per-file auto-
                                  detection]

  --pyi                           Format all input files like typing stubs
                                  regardless of file extension (useful when
                                  piping source on standard input).

  --ipynb                         Format all input files like Jupyter
                                  Notebooks regardless of file extension
                                  (useful when piping source on standard
                                  input).

  -S, --skip-string-normalization
                                  Don't normalize string quotes or prefixes.
  -C, --skip-magic-trailing-comma
                                  Don't use trailing commas as a reason to
                                  split lines.

  --check                         Don't write the files back, just return the
                                  status. Return code 0 means nothing would
                                  change. Return code 1 means some files would
                                  be reformatted. Return code 123 means there
                                  was an internal error.

  --diff                          Don't write the files back, just output a
                                  diff for each file on stdout.

  --color / --no-color            Show colored diff. Only applies when
                                  `--diff` is given.

  --fast / --safe                 If --fast given, skip temporary sanity
                                  checks. [default: --safe]

  --required-version TEXT         Require a specific version of Black to be
                                  running (useful for unifying results across
                                  many environments e.g. with a pyproject.toml
                                  file).

  --include TEXT                  A regular expression that matches files and
                                  directories that should be included on
                                  recursive searches. An empty value means all
                                  files are included regardless of the name.
                                  Use forward slashes for directories on all
                                  platforms (Windows, too). Exclusions are
                                  calculated first, inclusions later.
                                  [default: (\.pyi?|\.ipynb)$]

  --exclude TEXT                  A regular expression that matches files and
                                  directories that should be excluded on
                                  recursive searches. An empty value means no
                                  paths are excluded. Use forward slashes for
                                  directories on all platforms (Windows, too).
                                  Exclusions are calculated first, inclusions
                                  later. [default: /(\.direnv|\.eggs|\.git|\.h
                                  g|\.mypy_cache|\.nox|\.tox|\.venv|venv|\.svn
                                  |_build|buck-out|build|dist)/]

  --extend-exclude TEXT           Like --exclude, but adds additional files
                                  and directories on top of the excluded ones.
                                  (Useful if you simply want to add to the
                                  default)

  --force-exclude TEXT            Like --exclude, but files and directories
                                  matching this regex will be excluded even
                                  when they are passed explicitly as
                                  arguments.

  --stdin-filename TEXT           The name of the file when passing it through
                                  stdin. Useful to make sure Black will
                                  respect --force-exclude option on some
                                  editors that rely on using stdin.

  -q, --quiet                     Don't emit non-error messages to stderr.
                                  Errors are still emitted; silence those with
                                  2>/dev/null.

  -v, --verbose                   Also emit messages to stderr about files
                                  that were not changed or were ignored due to
                                  exclusion patterns.

  --version                       Show the version and exit.
  --config FILE                   Read configuration from FILE path.
  -h, --help                      Show this message and exit.

Installation on mega-linter Docker image

PIP packages (Python):
- black

Example success log

Results of black linter (version 19.10)
See documentation on https://nvuillam.github.io/mega-linter/descriptors/python_black/
-----------------------------------------------

[SUCCESS] .automation/test/python/python_good_1.py
    All done! ✨ 🍰 ✨
    1 file would be left unchanged.

Example error log

Results of black linter (version 19.10)
See documentation on https://nvuillam.github.io/mega-linter/descriptors/python_black/
-----------------------------------------------

[ERROR] .automation/test/python/python_bad_1.py
    error: cannot format .automation/test/python/python_bad_1.py: Cannot parse: 15:23: if github_token is None
    Oh no! 💥 💔 💥
    1 file would fail to reformat.