blacksin 20.8b1.post0
The uncompromising code formatter.
License: MIT
Requires Python: >=3.6
Keywords: automation formatter yapf autopep8 pyfmt gofmt rustfmt

> **This is a fork which adds an option to prefer single quotes. Nothing else has been
> changed.**
>
> Its cli is still called `black`, but the distribution name to use in `pip install` is
> named `blacksin` (because some people may consider a single-quote fork a mortal sin,
> and single quotes...)

![Black Logo](https://raw.githubusercontent.com/psf/black/master/docs/_static/logo2-readme.png)

<h2 align="center">The 'Uncompromising' Code Formatter</h2>

<p align="center">
<a href="https://travis-ci.com/ThiefMaster/blacksin"><img alt="Build Status" src="https://travis-ci.com/ThiefMaster/blacksin.svg?branch=single"></a>
<a href="https://github.com/ThiefMaster/blacksin/actions"><img alt="Actions Status" src="https://github.com/ThiefMaster/blacksin/workflows/Test/badge.svg"></a>
<a href="https://github.com/ThiefMaster/blacksin/actions"><img alt="Actions Status" src="https://github.com/ThiefMaster/blacksin/workflows/Primer/badge.svg"></a>
<a href="https://coveralls.io/github/ThiefMaster/blacksin?branch=master"><img alt="Coverage Status" src="https://coveralls.io/repos/github/ThiefMaster/blacksin/badge.svg?branch=master"></a>
<a href="https://github.com/ThiefMaster/blacksin/blob/master/LICENSE"><img alt="License: MIT" src="https://black.readthedocs.io/en/stable/_static/license.svg"></a>
<a href="https://pypi.org/project/blacksin/"><img alt="PyPI" src="https://img.shields.io/pypi/v/blacksin"></a>
<a href="https://pepy.tech/project/blacksin"><img alt="Downloads" src="https://pepy.tech/badge/blacksin"></a>
<a href="https://github.com/psf/black"><img alt="Code style: black" src="https://img.shields.io/badge/code%20style-black-000000.svg"></a>
</p>

> “Any color you like.”

_Black_ is the uncompromising Python code formatter. By using it, you agree to cede
control over minutiae of hand-formatting. In return, _Black_ gives you speed,
determinism, and freedom from `pycodestyle` nagging about formatting. You will save time
and mental energy for more important matters.

Blackened code looks the same regardless of the project you're reading. Formatting
becomes transparent after a while and you can focus on the content instead.

_Black_ makes code review faster by producing the smallest diffs possible.

Try it out now using the [Black Playground](https://black.now.sh). Watch the
[PyCon 2019 talk](https://youtu.be/esZLCuWs_2Y) to learn more.

---

_Contents:_ **[Installation and usage](#installation-and-usage)** |
**[Code style](#the-black-code-style)** | **[Pragmatism](#pragmatism)** |
**[pyproject.toml](#pyprojecttoml)** | **[Editor integration](#editor-integration)** |
**[blackd](#blackd)** | **[black-primer](#black-primer)** |
**[Version control integration](#version-control-integration)** |
**[GitHub Actions](#github-actions)** |
**[Ignoring unmodified files](#ignoring-unmodified-files)** | **[Used by](#used-by)** |
**[Testimonials](#testimonials)** | **[Show your style](#show-your-style)** |
**[Contributing](#contributing-to-black)** | **[Change log](#change-log)** |
**[Authors](#authors)**

---

## Installation and usage

### Installation

_Black_ can be installed by running `pip install blacksin`. It requires Python 3.6.0+ to
run but you can reformat Python 2 code with it, too.

#### Install from GitHub

If you can't wait for the latest _hotness_ and want to install from GitHub, use:

`pip install git+git://github.com/ThiefMaster/blacksin`

### Usage

To get started right away with sensible defaults:

```sh
black {source_file_or_directory}
```

You can run _Black_ as a package if running it as a script doesn't work:

```sh
python -m black {source_file_or_directory}
```

### Command line options

_Black_ doesn't provide many options. You can list them by running `black --help`:

```text
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).

  -S, --skip-string-normalization
                                  Don't normalize string quotes or prefixes.
  --single-quotes                 Prefer single quotes when normalizing strings.
  --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]

  --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?$]

  --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: /(\.eggs|\.git|\.hg|\.mypy
                                  _cache|\.nox|\.tox|\.venv|\.svn|_build|buck-
                                  out|build|dist)/]

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

  -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
                                  --exclude=.

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

_Black_ is a well-behaved Unix-style command-line tool:

- it does nothing if no sources are passed to it;
- it will read from standard input and write to standard output if `-` is used as the
  filename;
- it only outputs messages to users on standard error;
- exits with code 0 unless an internal error occurred (or `--check` was used).

### Using _Black_ with other tools

While _Black_ enforces formatting that conforms to PEP 8, other tools may raise warnings
about _Black_'s changes or will overwrite _Black_'s changes. A good example of this is
[isort](https://pypi.org/p/isort). Since _Black_ is barely configurable, these tools
should be configured to neither warn about nor overwrite _Black_'s changes.

Actual details on _Black_ compatible configurations for various tools can be found in
[compatible_configs](https://github.com/psf/black/blob/master/docs/compatible_configs.md#black-compatible-configurations).

### Migrating your code style without ruining git blame

A long-standing argument against moving to automated code formatters like _Black_ is
that the migration will clutter up the output of `git blame`. This was a valid argument,
but since Git version 2.23, Git natively supports
[ignoring revisions in blame](https://git-scm.com/docs/git-blame#Documentation/git-blame.txt---ignore-revltrevgt)
with the `--ignore-rev` option. You can also pass a file listing the revisions to ignore
using the `--ignore-revs-file` option. The changes made by the revision will be ignored
when assigning blame. Lines modified by an ignored revision will be blamed on the
previous revision that modified those lines.

So when migrating your project's code style to _Black_, reformat everything and commit
the changes (preferably in one massive commit). Then put the full 40 characters commit
identifier(s) into a file.

```
# Migrate code style to Black
5b4ab991dede475d393e9d69ec388fd6bd949699
```

Afterwards, you can pass that file to `git blame` and see clean and meaningful blame
information.

```console
$ git blame important.py --ignore-revs-file .git-blame-ignore-revs
7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 1) def very_important_function(text, file):
abdfd8b0 (Alice Doe  2019-09-23 11:39:32 -0400 2)     text = text.lstrip()
7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 3)     with open(file, "r+") as f:
7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 4)         f.write(formatted)
```

You can even configure `git` to automatically ignore revisions listed in a file on every
call to `git blame`.

```console
$ git config blame.ignoreRevsFile .git-blame-ignore-revs
```

**The one caveat is that GitHub and GitLab do not yet support ignoring revisions using
their native UI of blame.** So blame information will be cluttered with a reformatting
commit on those platforms. (If you'd like this feature, there's an open issue for
[GitLab](https://gitlab.com/gitlab-org/gitlab/-/issues/31423) and please let GitHub
know!)

### NOTE: This is a beta product

_Black_ is already [successfully used](https://github.com/psf/black#used-by) by many
projects, small and big. It also sports a decent test suite. However, it is still very
new. Things will probably be wonky for a while. This is made explicit by the "Beta"
trove classifier, as well as by the "b" in the version number. What this means for you
is that **until the formatter becomes stable, you should expect some formatting to
change in the future**. That being said, no drastic stylistic changes are planned,
mostly responses to bug reports.

Also, as a temporary safety measure, _Black_ will check that the reformatted code still
produces a valid AST that is equivalent to the original. This slows it down. If you're
feeling confident, use `--fast`.

## The _Black_ code style

_Black_ is a PEP 8 compliant opinionated formatter. _Black_ reformats entire files in
place. It is not configurable. It doesn't take previous formatting into account. Your
main option of configuring _Black_ is that it doesn't reformat blocks that start with
`# fmt: off` and end with `# fmt: on`. `# fmt: on/off` have to be on the same level of
indentation. To learn more about _Black_'s opinions, to go
[the_black_code_style](https://github.com/psf/black/blob/master/docs/the_black_code_style.md).

Please refer to this document before submitting an issue. What seems like a bug might be
intended behaviour.

## Pragmatism

Early versions of _Black_ used to be absolutist in some respects. They took after its
initial author. This was fine at the time as it made the implementation simpler and
there were not many users anyway. Not many edge cases were reported. As a mature tool,
_Black_ does make some exceptions to rules it otherwise holds. This
[section](https://github.com/psf/black/blob/master/docs/the_black_code_style.md#pragmatism)
of `the_black_code_style` describes what those exceptions are and why this is the case.

Please refer to this document before submitting an issue just like with the document
above. What seems like a bug might be intended behaviour.

## pyproject.toml

_Black_ is able to read project-specific default values for its command line options
from a `pyproject.toml` file. This is especially useful for specifying custom
`--include` and `--exclude` patterns for your project.

**Pro-tip**: If you're asking yourself "Do I need to configure anything?" the answer is
"No". _Black_ is all about sensible defaults.

### What on Earth is a `pyproject.toml` file?

[PEP 518](https://www.python.org/dev/peps/pep-0518/) defines `pyproject.toml` as a
configuration file to store build system requirements for Python projects. With the help
of tools like [Poetry](https://python-poetry.org/) or
[Flit](https://flit.readthedocs.io/en/latest/) it can fully replace the need for
`setup.py` and `setup.cfg` files.

### Where _Black_ looks for the file

By default _Black_ looks for `pyproject.toml` starting from the common base directory of
all files and directories passed on the command line. If it's not there, it looks in
parent directories. It stops looking when it finds the file, or a `.git` directory, or a
`.hg` directory, or the root of the file system, whichever comes first.

If you're formatting standard input, _Black_ will look for configuration starting from
the current working directory.

You can also explicitly specify the path to a particular file that you want with
`--config`. In this situation _Black_ will not look for any other file.

If you're running with `--verbose`, you will see a blue message if a file was found and
used.

Please note `blackd` will not use `pyproject.toml` configuration.

### Configuration format

As the file extension suggests, `pyproject.toml` is a
[TOML](https://github.com/toml-lang/toml) file. It contains separate sections for
different tools. _Black_ is using the `[tool.black]` section. The option keys are the
same as long names of options on the command line.

Note that you have to use single-quoted strings in TOML for regular expressions. It's
the equivalent of r-strings in Python. Multiline strings are treated as verbose regular
expressions by Black. Use `[ ]` to denote a significant space character.

<details>
<summary>Example <code>pyproject.toml</code></summary>

```toml
[tool.black]
line-length = 88
target-version = ['py37']
include = '\.pyi?$'
exclude = '''

(
  /(
      \.eggs         # exclude a few common directories in the
    | \.git          # root of the project
    | \.hg
    | \.mypy_cache
    | \.tox
    | \.venv
    | _build
    | buck-out
    | build
    | dist
  )/
  | foo.py           # also separately exclude a file named foo.py in
                     # the root of the project
)
'''
```

</details>

### Lookup hierarchy

Command-line options have defaults that you can see in `--help`. A `pyproject.toml` can
override those defaults. Finally, options provided by the user on the command line
override both.

_Black_ will only ever use one `pyproject.toml` file during an entire run. It doesn't
look for multiple files, and doesn't compose configuration from different levels of the
file hierarchy.

## Editor integration

_Black_ can be integrated into many editors with plugins. They let you run _Black_ on
your code with the ease of doing it in your editor. To get started using _Black_ in your
editor of choice, please see
[editor_integration](https://github.com/psf/black/blob/master/docs/editor_integration.md).

Patches are welcome for editors without an editor integration or plugin! More
information can be found in
[editor_integration](https://github.com/psf/black/blob/master/docs/editor_integration.md#other-editors).

## blackd

`blackd` is a small HTTP server that exposes Black's functionality over a simple
protocol. The main benefit of using it is to avoid paying the cost of starting up a new
Black process every time you want to blacken a file. Please refer to
[blackd](https://github.com/psf/black/blob/master/docs/blackd.md) to get the ball
rolling.

## black-primer

`black-primer` is a tool built for CI (and humans) to have _Black_ `--check` a number of
(configured in `primer.json`) Git accessible projects in parallel.
[black_primer](https://github.com/psf/black/blob/master/docs/black_primer.md) has more
information regarding its usage and configuration.

(A PR adding Mercurial support will be accepted.)

## Version control integration

Use [pre-commit](https://pre-commit.com/). Once you
[have it installed](https://pre-commit.com/#install), add this to the
`.pre-commit-config.yaml` in your repository:

```yaml
repos:
  - repo: https://github.com/psf/black
    rev: 20.8b1 # Replace by any tag/version: https://github.com/psf/black/tags
    hooks:
      - id: black
        language_version: python3 # Should be a command that runs python3.6+
```

Then run `pre-commit install` and you're ready to go.

Avoid using `args` in the hook. Instead, store necessary configuration in
`pyproject.toml` so that editors and command-line usage of Black all behave consistently
for your project. See _Black_'s own
[pyproject.toml](https://github.com/psf/black/blob/master/pyproject.toml) for an
example.

If you're already using Python 3.7, switch the `language_version` accordingly. Finally,
`stable` is a branch that tracks the latest release on PyPI. If you'd rather run on
master, this is also an option.

## GitHub Actions

Create a file named `.github/workflows/black.yml` inside your repository with:

```yaml
name: Lint

on: [push, pull_request]

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-python@v2
      - uses: psf/black@stable
```

## Ignoring unmodified files

_Black_ remembers files it has already formatted, unless the `--diff` flag is used or
code is passed via standard input. This information is stored per-user. The exact
location of the file depends on the _Black_ version and the system on which _Black_ is
run. The file is non-portable. The standard location on common operating systems is:

- Windows:
  `C:\\Users\<username>\AppData\Local\black\black\Cache\<version>\cache.<line-length>.<file-mode>.pickle`
- macOS:
  `/Users/<username>/Library/Caches/black/<version>/cache.<line-length>.<file-mode>.pickle`
- Linux:
  `/home/<username>/.cache/black/<version>/cache.<line-length>.<file-mode>.pickle`

`file-mode` is an int flag that determines whether the file was formatted as 3.6+ only,
as .pyi, and whether string normalization was omitted.

To override the location of these files on macOS or Linux, set the environment variable
`XDG_CACHE_HOME` to your preferred location. For example, if you want to put the cache
in the directory you're running _Black_ from, set `XDG_CACHE_HOME=.cache`. _Black_ will
then write the above files to `.cache/black/<version>/`.

## Used by

The following notable open-source projects trust _Black_ with enforcing a consistent
code style: pytest, tox, Pyramid, Django Channels, Hypothesis, attrs, SQLAlchemy,
Poetry, PyPA applications (Warehouse, Bandersnatch, Pipenv, virtualenv), pandas, Pillow,
every Datadog Agent Integration, Home Assistant.

The following organizations use _Black_: Facebook, Dropbox, Mozilla, Quora.

Are we missing anyone? Let us know.

## Testimonials

**Dusty Phillips**,
[writer](https://smile.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=dusty+phillips):

> _Black_ is opinionated so you don't have to be.

**Hynek Schlawack**, [creator of `attrs`](https://www.attrs.org/), core developer of
Twisted and CPython:

> An auto-formatter that doesn't suck is all I want for Xmas!

**Carl Meyer**, [Django](https://www.djangoproject.com/) core developer:

> At least the name is good.

**Kenneth Reitz**, creator of [`requests`](http://python-requests.org/) and
[`pipenv`](https://readthedocs.org/projects/pipenv/):

> This vastly improves the formatting of our code. Thanks a ton!

## Show your style

Use the badge in your project's README.md:

```md
[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
```

Using the badge in README.rst:

```
.. image:: https://img.shields.io/badge/code%20style-black-000000.svg
    :target: https://github.com/psf/black
```

Looks like this:
[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)

## License

MIT

## Contributing to _Black_

In terms of inspiration, _Black_ is about as configurable as _gofmt_. This is
deliberate.

Bug reports and fixes are always welcome! However, before you suggest a new feature or
configuration knob, ask yourself why you want it. If it enables better integration with
some workflow, fixes an inconsistency, speeds things up, and so on - go for it! On the
other hand, if your answer is "because I don't like a particular formatting" then you're
not ready to embrace _Black_ yet. Such changes are unlikely to get accepted. You can
still try but prepare to be disappointed.

More details can be found in
[CONTRIBUTING](https://github.com/psf/black/blob/master/CONTRIBUTING.md).

## Change log

The log's become rather long. It moved to its own file.

See [CHANGES](https://github.com/psf/black/blob/master/CHANGES.md).

## Authors

Glued together by [Łukasz Langa](mailto:lukasz@langa.pl).

Maintained with [Carol Willing](mailto:carolcode@willingconsulting.com),
[Carl Meyer](mailto:carl@oddbird.net),
[Jelle Zijlstra](mailto:jelle.zijlstra@gmail.com),
[Mika Naylor](mailto:mail@autophagy.io),
[Zsolt Dollenstein](mailto:zsol.zsol@gmail.com), and
[Cooper Lees](mailto:me@cooperlees.com).

Multiple contributions by:

- [Abdur-Rahmaan Janhangeer](mailto:arj.python@gmail.com)
- [Adam Johnson](mailto:me@adamj.eu)
- [Adam Williamson](mailto:adamw@happyassassin.net)
- [Alexander Huynh](mailto:github@grande.coffee)
- [Alex Vandiver](mailto:github@chmrr.net)
- [Allan Simon](mailto:allan.simon@supinfo.com)
- Anders-Petter Ljungquist
- [Andrew Thorp](mailto:andrew.thorp.dev@gmail.com)
- [Andrew Zhou](mailto:andrewfzhou@gmail.com)
- [Andrey](mailto:dyuuus@yandex.ru)
- [Andy Freeland](mailto:andy@andyfreeland.net)
- [Anthony Sottile](mailto:asottile@umich.edu)
- [Arjaan Buijk](mailto:arjaan.buijk@gmail.com)
- [Arnav Borbornah](mailto:arnavborborah11@gmail.com)
- [Artem Malyshev](mailto:proofit404@gmail.com)
- [Asger Hautop Drewsen](mailto:asgerdrewsen@gmail.com)
- [Augie Fackler](mailto:raf@durin42.com)
- [Aviskar KC](mailto:aviskarkc10@gmail.com)
- Batuhan Taşkaya
- [Benjamin Wohlwend](mailto:bw@piquadrat.ch)
- [Benjamin Woodruff](mailto:github@benjam.info)
- [Bharat Raghunathan](mailto:bharatraghunthan9767@gmail.com)
- [Brandt Bucher](mailto:brandtbucher@gmail.com)
- [Brett Cannon](mailto:brett@python.org)
- [Bryan Bugyi](mailto:bryan.bugyi@rutgers.edu)
- [Bryan Forbes](mailto:bryan@reigndropsfall.net)
- [Calum Lind](mailto:calumlind@gmail.com)
- [Charles](mailto:peacech@gmail.com)
- Charles Reid
- [Christian Clauss](mailto:cclauss@bluewin.ch)
- [Christian Heimes](mailto:christian@python.org)
- [Chuck Wooters](mailto:chuck.wooters@microsoft.com)
- [Chris Rose](mailto:offline@offby1.net)
- Codey Oxley
- [Cong](mailto:congusbongus@gmail.com)
- [Cooper Ry Lees](mailto:me@cooperlees.com)
- [Dan Davison](mailto:dandavison7@gmail.com)
- [Daniel Hahler](mailto:github@thequod.de)
- [Daniel M. Capella](mailto:polycitizen@gmail.com)
- Daniele Esposti
- [David Hotham](mailto:david.hotham@metaswitch.com)
- [David Lukes](mailto:dafydd.lukes@gmail.com)
- [David Szotten](mailto:davidszotten@gmail.com)
- [Denis Laxalde](mailto:denis@laxalde.org)
- [Douglas Thor](mailto:dthor@transphormusa.com)
- dylanjblack
- [Eli Treuherz](mailto:eli@treuherz.com)
- [Emil Hessman](mailto:emil@hessman.se)
- [Felix Kohlgrüber](mailto:felix.kohlgrueber@gmail.com)
- [Florent Thiery](mailto:fthiery@gmail.com)
- Francisco
- [Giacomo Tagliabue](mailto:giacomo.tag@gmail.com)
- [Greg Gandenberger](mailto:ggandenberger@shoprunner.com)
- [Gregory P. Smith](mailto:greg@krypto.org)
- Gustavo Camargo
- hauntsaninja
- [Hadi Alqattan](mailto:alqattanhadizaki@gmail.com)
- [Heaford](mailto:dan@heaford.com)
- [Hugo Barrera](mailto::hugo@barrera.io)
- Hugo van Kemenade
- [Hynek Schlawack](mailto:hs@ox.cx)
- [Ivan Katanić](mailto:ivan.katanic@gmail.com)
- [Jakub Kadlubiec](mailto:jakub.kadlubiec@skyscanner.net)
- [Jakub Warczarek](mailto:jakub.warczarek@gmail.com)
- [Jan Hnátek](mailto:jan.hnatek@gmail.com)
- [Jason Fried](mailto:me@jasonfried.info)
- [Jason Friedland](mailto:jason@friedland.id.au)
- [jgirardet](mailto:ijkl@netc.fr)
- Jim Brännlund
- [Jimmy Jia](mailto:tesrin@gmail.com)
- [Joe Antonakakis](mailto:jma353@cornell.edu)
- [Jon Dufresne](mailto:jon.dufresne@gmail.com)
- [Jonas Obrist](mailto:ojiidotch@gmail.com)
- [Jonty Wareing](mailto:jonty@jonty.co.uk)
- [Jose Nazario](mailto:jose.monkey.org@gmail.com)
- [Joseph Larson](mailto:larson.joseph@gmail.com)
- [Josh Bode](mailto:joshbode@fastmail.com)
- [Josh Holland](mailto:anowlcalledjosh@gmail.com)
- [José Padilla](mailto:jpadilla@webapplicate.com)
- [Juan Luis Cano Rodríguez](mailto:hello@juanlu.space)
- [kaiix](mailto:kvn.hou@gmail.com)
- [Katie McLaughlin](mailto:katie@glasnt.com)
- Katrin Leinweber
- [Keith Smiley](mailto:keithbsmiley@gmail.com)
- [Kenyon Ralph](mailto:kenyon@kenyonralph.com)
- [Kevin Kirsche](mailto:Kev.Kirsche+GitHub@gmail.com)
- [Kyle Hausmann](mailto:kyle.hausmann@gmail.com)
- [Kyle Sunden](mailto:sunden@wisc.edu)
- Lawrence Chan
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- [Luka Sterbic](mailto:luka.sterbic@gmail.com)
- [LukasDrude](mailto:mail@lukas-drude.de)
- Mahmoud Hossam
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- [Matthew Clapp](mailto:itsayellow+dev@gmail.com)
- [Matthew Walster](mailto:matthew@walster.org)
- Max Smolens
- [Michael Aquilina](mailto:michaelaquilina@gmail.com)
- [Michael Flaxman](mailto:michael.flaxman@gmail.com)
- [Michael J. Sullivan](mailto:sully@msully.net)
- [Michael McClimon](mailto:michael@mcclimon.org)
- [Miguel Gaiowski](mailto:miggaiowski@gmail.com)
- [Mike](mailto:roshi@fedoraproject.org)
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- [Peter Grayson](mailto:pete@jpgrayson.net)
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- [Vishwas B Sharma](mailto:sharma.vishwas88@gmail.com)
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- Yazdan
- [Yngve Høiseth](mailto:yngve@hoiseth.net)
- [Yurii Karabas](mailto:1998uriyyo@gmail.com)
- [Zac Hatfield-Dodds](mailto:zac@zhd.dev)


## Change Log

### Unreleased

#### _Black_

- `Black` now respects `--skip-string-normalization` when normalizing multiline
  docstring quotes (#1637)

- `Black` no longer removes all empty lines between non-function code and decorators
  when formatting typing stubs. Now `Black` enforces a single empty line. (#1646)

- `Black` no longer adds an incorrect space after a parenthesized assignment expression
  in if/while statements (#1655)

- fixed a crash when PWD=/ on POSIX (#1631)

- fixed "I/O operation on closed file" when using --diff (#1664)

- Prevent coloured diff output being interleaved with multiple files (#1673)

- Added support for PEP 614 relaxed decorator syntax on python 3.9 (#1711)

### 20.8b1

#### _Packaging_

- explicitly depend on Click 7.1.2 or newer as `Black` no longer works with versions
  older than 7.0

### 20.8b0

#### _Black_

- re-implemented support for explicit trailing commas: now it works consistently within
  any bracket pair, including nested structures (#1288 and duplicates)

- `Black` now reindents docstrings when reindenting code around it (#1053)

- `Black` now shows colored diffs (#1266)

- `Black` is now packaged using 'py3' tagged wheels (#1388)

- `Black` now supports Python 3.8 code, e.g. star expressions in return statements
  (#1121)

- `Black` no longer normalizes capital R-string prefixes as those have a
  community-accepted meaning (#1244)

- `Black` now uses exit code 2 when specified configuration file doesn't exit (#1361)

- `Black` now works on AWS Lambda (#1141)

- added `--force-exclude` argument (#1032)

- removed deprecated `--py36` option (#1236)

- fixed `--diff` output when EOF is encountered (#526)

- fixed `# fmt: off` handling around decorators (#560)

- fixed unstable formatting with some `# type: ignore` comments (#1113)

- fixed invalid removal on organizing brackets followed by indexing (#1575)

- introduced `black-primer`, a CI tool that allows us to run regression tests against
  existing open source users of Black (#1402)

- introduced property-based fuzzing to our test suite based on Hypothesis and
  Hypothersmith (#1566)

- implemented experimental and disabled by default long string rewrapping (#1132),
  hidden under a `--experimental-string-processing` flag while it's being worked on;
  this is an undocumented and unsupported feature, you lose Internet points for
  depending on it (#1609)

#### Vim plugin

- prefer virtualenv packages over global packages (#1383)

### 19.10b0

- added support for PEP 572 assignment expressions (#711)

- added support for PEP 570 positional-only arguments (#943)

- added support for async generators (#593)

- added support for pre-splitting collections by putting an explicit trailing comma
  inside (#826)

- added `black -c` as a way to format code passed from the command line (#761)

- --safe now works with Python 2 code (#840)

- fixed grammar selection for Python 2-specific code (#765)

- fixed feature detection for trailing commas in function definitions and call sites
  (#763)

- `# fmt: off`/`# fmt: on` comment pairs placed multiple times within the same block of
  code now behave correctly (#1005)

- _Black_ no longer crashes on Windows machines with more than 61 cores (#838)

- _Black_ no longer crashes on standalone comments prepended with a backslash (#767)

- _Black_ no longer crashes on `from` ... `import` blocks with comments (#829)

- _Black_ no longer crashes on Python 3.7 on some platform configurations (#494)

- _Black_ no longer fails on comments in from-imports (#671)

- _Black_ no longer fails when the file starts with a backslash (#922)

- _Black_ no longer merges regular comments with type comments (#1027)

- _Black_ no longer splits long lines that contain type comments (#997)

- removed unnecessary parentheses around `yield` expressions (#834)

- added parentheses around long tuples in unpacking assignments (#832)

- added parentheses around complex powers when they are prefixed by a unary operator
  (#646)

- fixed bug that led _Black_ format some code with a line length target of 1 (#762)

- _Black_ no longer introduces quotes in f-string subexpressions on string boundaries
  (#863)

- if _Black_ puts parenthesis around a single expression, it moves comments to the
  wrapped expression instead of after the brackets (#872)

- `blackd` now returns the version of _Black_ in the response headers (#1013)

- `blackd` can now output the diff of formats on source code when the `X-Diff` header is
  provided (#969)

### 19.3b0

- new option `--target-version` to control which Python versions _Black_-formatted code
  should target (#618)

- deprecated `--py36` (use `--target-version=py36` instead) (#724)

- _Black_ no longer normalizes numeric literals to include `_` separators (#696)

- long `del` statements are now split into multiple lines (#698)

- type comments are no longer mangled in function signatures

- improved performance of formatting deeply nested data structures (#509)

- _Black_ now properly formats multiple files in parallel on Windows (#632)

- _Black_ now creates cache files atomically which allows it to be used in parallel
  pipelines (like `xargs -P8`) (#673)

- _Black_ now correctly indents comments in files that were previously formatted with
  tabs (#262)

- `blackd` now supports CORS (#622)

### 18.9b0

- numeric literals are now formatted by _Black_ (#452, #461, #464, #469):

  - numeric literals are normalized to include `_` separators on Python 3.6+ code

  - added `--skip-numeric-underscore-normalization` to disable the above behavior and
    leave numeric underscores as they were in the input

  - code with `_` in numeric literals is recognized as Python 3.6+

  - most letters in numeric literals are lowercased (e.g., in `1e10`, `0x01`)

  - hexadecimal digits are always uppercased (e.g. `0xBADC0DE`)

- added `blackd`, see [its documentation](#blackd) for more info (#349)

- adjacent string literals are now correctly split into multiple lines (#463)

- trailing comma is now added to single imports that don't fit on a line (#250)

- cache is now populated when `--check` is successful for a file which speeds up
  consecutive checks of properly formatted unmodified files (#448)

- whitespace at the beginning of the file is now removed (#399)

- fixed mangling [pweave](http://mpastell.com/pweave/) and
  [Spyder IDE](https://www.spyder-ide.org/) special comments (#532)

- fixed unstable formatting when unpacking big tuples (#267)

- fixed parsing of `__future__` imports with renames (#389)

- fixed scope of `# fmt: off` when directly preceding `yield` and other nodes (#385)

- fixed formatting of lambda expressions with default arguments (#468)

- fixed `async for` statements: _Black_ no longer breaks them into separate lines (#372)

- note: the Vim plugin stopped registering `,=` as a default chord as it turned out to
  be a bad idea (#415)

### 18.6b4

- hotfix: don't freeze when multiple comments directly precede `# fmt: off` (#371)

### 18.6b3

- typing stub files (`.pyi`) now have blank lines added after constants (#340)

- `# fmt: off` and `# fmt: on` are now much more dependable:

  - they now work also within bracket pairs (#329)

  - they now correctly work across function/class boundaries (#335)

  - they now work when an indentation block starts with empty lines or misaligned
    comments (#334)

- made Click not fail on invalid environments; note that Click is right but the
  likelihood we'll need to access non-ASCII file paths when dealing with Python source
  code is low (#277)

- fixed improper formatting of f-strings with quotes inside interpolated expressions
  (#322)

- fixed unnecessary slowdown when long list literals where found in a file

- fixed unnecessary slowdown on AST nodes with very many siblings

- fixed cannibalizing backslashes during string normalization

- fixed a crash due to symbolic links pointing outside of the project directory (#338)

### 18.6b2

- added `--config` (#65)

- added `-h` equivalent to `--help` (#316)

- fixed improper unmodified file caching when `-S` was used

- fixed extra space in string unpacking (#305)

- fixed formatting of empty triple quoted strings (#313)

- fixed unnecessary slowdown in comment placement calculation on lines without comments

### 18.6b1

- hotfix: don't output human-facing information on stdout (#299)

- hotfix: don't output cake emoji on non-zero return code (#300)

### 18.6b0

- added `--include` and `--exclude` (#270)

- added `--skip-string-normalization` (#118)

- added `--verbose` (#283)

- the header output in `--diff` now actually conforms to the unified diff spec

- fixed long trivial assignments being wrapped in unnecessary parentheses (#273)

- fixed unnecessary parentheses when a line contained multiline strings (#232)

- fixed stdin handling not working correctly if an old version of Click was used (#276)

- _Black_ now preserves line endings when formatting a file in place (#258)

### 18.5b1

- added `--pyi` (#249)

- added `--py36` (#249)

- Python grammar pickle caches are stored with the formatting caches, making _Black_
  work in environments where site-packages is not user-writable (#192)

- _Black_ now enforces a PEP 257 empty line after a class-level docstring (and/or
  fields) and the first method

- fixed invalid code produced when standalone comments were present in a trailer that
  was omitted from line splitting on a large expression (#237)

- fixed optional parentheses being removed within `# fmt: off` sections (#224)

- fixed invalid code produced when stars in very long imports were incorrectly wrapped
  in optional parentheses (#234)

- fixed unstable formatting when inline comments were moved around in a trailer that was
  omitted from line splitting on a large expression (#238)

- fixed extra empty line between a class declaration and the first method if no class
  docstring or fields are present (#219)

- fixed extra empty line between a function signature and an inner function or inner
  class (#196)

### 18.5b0

- call chains are now formatted according to the
  [fluent interfaces](https://en.wikipedia.org/wiki/Fluent_interface) style (#67)

- data structure literals (tuples, lists, dictionaries, and sets) are now also always
  exploded like imports when they don't fit in a single line (#152)

- slices are now formatted according to PEP 8 (#178)

- parentheses are now also managed automatically on the right-hand side of assignments
  and return statements (#140)

- math operators now use their respective priorities for delimiting multiline
  expressions (#148)

- optional parentheses are now omitted on expressions that start or end with a bracket
  and only contain a single operator (#177)

- empty parentheses in a class definition are now removed (#145, #180)

- string prefixes are now standardized to lowercase and `u` is removed on Python 3.6+
  only code and Python 2.7+ code with the `unicode_literals` future import (#188, #198,
  #199)

- typing stub files (`.pyi`) are now formatted in a style that is consistent with PEP
  484 (#207, #210)

- progress when reformatting many files is now reported incrementally

- fixed trailers (content with brackets) being unnecessarily exploded into their own
  lines after a dedented closing bracket (#119)

- fixed an invalid trailing comma sometimes left in imports (#185)

- fixed non-deterministic formatting when multiple pairs of removable parentheses were
  used (#183)

- fixed multiline strings being unnecessarily wrapped in optional parentheses in long
  assignments (#215)

- fixed not splitting long from-imports with only a single name

- fixed Python 3.6+ file discovery by also looking at function calls with unpacking.
  This fixed non-deterministic formatting if trailing commas where used both in function
  signatures with stars and function calls with stars but the former would be
  reformatted to a single line.

- fixed crash on dealing with optional parentheses (#193)

- fixed "is", "is not", "in", and "not in" not considered operators for splitting
  purposes

- fixed crash when dead symlinks where encountered

### 18.4a4

- don't populate the cache on `--check` (#175)

### 18.4a3

- added a "cache"; files already reformatted that haven't changed on disk won't be
  reformatted again (#109)

- `--check` and `--diff` are no longer mutually exclusive (#149)

- generalized star expression handling, including double stars; this fixes
  multiplication making expressions "unsafe" for trailing commas (#132)

- _Black_ no longer enforces putting empty lines behind control flow statements (#90)

- _Black_ now splits imports like "Mode 3 + trailing comma" of isort (#127)

- fixed comment indentation when a standalone comment closes a block (#16, #32)

- fixed standalone comments receiving extra empty lines if immediately preceding a
  class, def, or decorator (#56, #154)

- fixed `--diff` not showing entire path (#130)

- fixed parsing of complex expressions after star and double stars in function calls
  (#2)

- fixed invalid splitting on comma in lambda arguments (#133)

- fixed missing splits of ternary expressions (#141)

### 18.4a2

- fixed parsing of unaligned standalone comments (#99, #112)

- fixed placement of dictionary unpacking inside dictionary literals (#111)

- Vim plugin now works on Windows, too

- fixed unstable formatting when encountering unnecessarily escaped quotes in a string
  (#120)

### 18.4a1

- added `--quiet` (#78)

- added automatic parentheses management (#4)

- added [pre-commit](https://pre-commit.com) integration (#103, #104)

- fixed reporting on `--check` with multiple files (#101, #102)

- fixed removing backslash escapes from raw strings (#100, #105)

### 18.4a0

- added `--diff` (#87)

- add line breaks before all delimiters, except in cases like commas, to better comply
  with PEP 8 (#73)

- standardize string literals to use double quotes (almost) everywhere (#75)

- fixed handling of standalone comments within nested bracketed expressions; _Black_
  will no longer produce super long lines or put all standalone comments at the end of
  the expression (#22)

- fixed 18.3a4 regression: don't crash and burn on empty lines with trailing whitespace
  (#80)

- fixed 18.3a4 regression: `# yapf: disable` usage as trailing comment would cause
  _Black_ to not emit the rest of the file (#95)

- when CTRL+C is pressed while formatting many files, _Black_ no longer freaks out with
  a flurry of asyncio-related exceptions

- only allow up to two empty lines on module level and only single empty lines within
  functions (#74)

### 18.3a4

- `# fmt: off` and `# fmt: on` are implemented (#5)

- automatic detection of deprecated Python 2 forms of print statements and exec
  statements in the formatted file (#49)

- use proper spaces for complex expressions in default values of typed function
  arguments (#60)

- only return exit code 1 when --check is used (#50)

- don't remove single trailing commas from square bracket indexing (#59)

- don't omit whitespace if the previous factor leaf wasn't a math operator (#55)

- omit extra space in kwarg unpacking if it's the first argument (#46)

- omit extra space in
  [Sphinx auto-attribute comments](http://www.sphinx-doc.org/en/stable/ext/autodoc.html#directive-autoattribute)
  (#68)

### 18.3a3

- don't remove single empty lines outside of bracketed expressions (#19)

- added ability to pipe formatting from stdin to stdin (#25)

- restored ability to format code with legacy usage of `async` as a name (#20, #42)

- even better handling of numpy-style array indexing (#33, again)

### 18.3a2

- changed positioning of binary operators to occur at beginning of lines instead of at
  the end, following
  [a recent change to PEP 8](https://github.com/python/peps/commit/c59c4376ad233a62ca4b3a6060c81368bd21e85b)
  (#21)

- ignore empty bracket pairs while splitting. This avoids very weirdly looking
  formattings (#34, #35)

- remove a trailing comma if there is a single argument to a call

- if top level functions were separated by a comment, don't put four empty lines after
  the upper function

- fixed unstable formatting of newlines with imports

- fixed unintentional folding of post scriptum standalone comments into last statement
  if it was a simple statement (#18, #28)

- fixed missing space in numpy-style array indexing (#33)

- fixed spurious space after star-based unary expressions (#31)

### 18.3a1

- added `--check`

- only put trailing commas in function signatures and calls if it's safe to do so. If
  the file is Python 3.6+ it's always safe, otherwise only safe if there are no `*args`
  or `**kwargs` used in the signature or call. (#8)

- fixed invalid spacing of dots in relative imports (#6, #13)

- fixed invalid splitting after comma on unpacked variables in for-loops (#23)

- fixed spurious space in parenthesized set expressions (#7)

- fixed spurious space after opening parentheses and in default arguments (#14, #17)

- fixed spurious space after unary operators when the operand was a complex expression
  (#15)

### 18.3a0

- first published version, Happy 🍰 Day 2018!

- alpha quality

- date-versioned (see: https://calver.org/)