<p align="center">
<a href="https://travis-ci.com/psf/black"><img alt="Build Status" src="https://travis-ci.com/psf/black.svg?branch=master"></a>
+<a href="https://github.com/psf/black/actions"><img alt="Actions Status" src="https://github.com/psf/black/workflows/Test/badge.svg"></a>
+<a href="https://github.com/psf/black/actions"><img alt="Actions Status" src="https://github.com/psf/black/workflows/Primer/badge.svg"></a>
<a href="https://black.readthedocs.io/en/stable/?badge=stable"><img alt="Documentation Status" src="https://readthedocs.org/projects/black/badge/?version=stable"></a>
<a href="https://coveralls.io/github/psf/black?branch=master"><img alt="Coverage Status" src="https://coveralls.io/repos/github/psf/black/badge.svg?branch=master"></a>
<a href="https://github.com/psf/black/blob/master/LICENSE"><img alt="License: MIT" src="https://black.readthedocs.io/en/stable/_static/license.svg"></a>
---
_Contents:_ **[Installation and usage](#installation-and-usage)** |
-**[Code style](#the-black-code-style)** | **[pyproject.toml](#pyprojecttoml)** |
-**[Editor integration](#editor-integration)** | **[blackd](#blackd)** |
+**[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)** |
**[Ignoring unmodified files](#ignoring-unmodified-files)** | **[Used by](#used-by)** |
**[Testimonials](#testimonials)** | **[Show your style](#show-your-style)** |
To get started right away with sensible defaults:
-```
+```sh
black {source_file_or_directory}
```
_Black_ doesn't provide many options. You can list them by running `black --help`:
```text
-black [OPTIONS] [SRC]...
+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]
Python versions that should be supported by
Black's output. [default: per-file auto-
detection]
- --py36 Allow using Python 3.6-only syntax on all
- input files. This will put trailing commas
- in function signatures and calls also after
- *args and **kwargs. Deprecated; use
- --target-version instead. [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.
--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
+ 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
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
directories on all platforms (Windows, too).
Exclusions are calculated first, inclusions
later. [default: /(\.eggs|\.git|\.hg|\.mypy
- _cache|\.nox|\.tox|\.venv|_build|buck-
+ _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
+ 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 PATH Read configuration from PATH.
+ --config FILE Read configuration from PATH.
-h, --help Show this message and exit.
```
- 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).
+
+### 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](#used-by) by many projects, small and big. It
j = [1,
2,
- 3,
+ 3
]
# out:
...
```
+_Black_ prefers parentheses over backslashes, and will remove backslashes if found.
+
+```py3
+# in:
+
+if some_short_rule1 \
+ and some_short_rule2:
+ ...
+
+# out:
+
+if some_short_rule1 and some_short_rule2:
+ ...
+
+
+# in:
+
+if some_long_rule1 \
+ and some_long_rule2:
+ ...
+
+# out:
+
+if (
+ some_long_rule1
+ and some_long_rule2
+):
+ ...
+
+```
+
+Backslashes and multiline strings are one of the two places in the Python grammar that
+break significant indentation. You never need backslashes, they are used to force the
+grammar to accept breaks that would otherwise be parse errors. That makes them confusing
+to look at and brittle to modify. This is why _Black_ always gets rid of them.
+
+If you're reaching for backslashes, that's a clear signal that you can do better if you
+slightly refactor your code. I hope some of the examples above show you that there are
+many ways in which you can do it.
+
+However there is one exception: `with` statements using multiple context managers.
+Python's grammar does not allow organizing parentheses around the series of context
+managers.
+
+We don't want formatting like:
+
+```py3
+with make_context_manager1() as cm1, make_context_manager2() as cm2, make_context_manager3() as cm3, make_context_manager4() as cm4:
+ ... # nothing to split on - line too long
+```
+
+So _Black_ will now format it like this:
+
+```py3
+with \
+ make_context_manager(1) as cm1, \
+ make_context_manager(2) as cm2, \
+ make_context_manager(3) as cm3, \
+ make_context_manager(4) as cm4 \
+:
+ ... # backslashes and an ugly stranded colon
+```
+
You might have noticed that closing brackets are always dedented and that a trailing
comma is always added. Such formatting produces smaller diffs; when you add or remove an
element, it's always just one line. Also, having the closing bracket dedented provides a
explains it. The tl;dr is "it's like highway speed limits, we won't bother you if you
overdo it by a few km/h".
+**If you're looking for a minimal, black-compatible flake8 configuration:**
+
+```ini
+[flake8]
+max-line-length = 88
+extend-ignore = E203
+```
+
### Empty lines
_Black_ avoids spurious vertical whitespace. This is in the spirit of PEP 8 which says
[recommends](https://www.python.org/dev/peps/pep-0008/#whitespace-in-expressions-and-statements)
to treat `:` in slices as a binary operator with the lowest priority, and to leave an
equal amount of space on either side, except if a parameter is omitted (e.g.
-`ham[1 + 1 :]`). It also states that for extended slices, both `:` operators have to
-have the same amount of spacing, except if a parameter is omitted (`ham[1 + 1 ::]`).
-_Black_ enforces these rules consistently.
+`ham[1 + 1 :]`). It recommends no spaces around `:` operators for "simple expressions"
+(`ham[lower:upper]`), and extra space for "complex expressions"
+(`ham[lower : upper + offset]`). _Black_ treats anything more than variable names as
+"complex" (`ham[lower : upper + 1]`). It also states that for extended slices, both `:`
+operators have to have the same amount of spacing, except if a parameter is omitted
+(`ham[1 + 1 ::]`). _Black_ enforces these rules consistently.
This behaviour may raise `E203 whitespace before ':'` warnings in style guide
enforcement tools like Flake8. Since `E203` is not PEP 8 compliant, you should tell
- for arguments that default to `None`, use `Optional[]` explicitly;
- use `float` instead of `Union[int, float]`.
+## 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 documents
+what those exceptions are and why this is the case.
+
+### The magic trailing comma
+
+_Black_ in general does not take existing formatting into account.
+
+However, there are cases where you put a short collection or function call in your code
+but you anticipate it will grow in the future.
+
+For example:
+
+```py3
+TRANSLATIONS = {
+ "en_us": "English (US)",
+ "pl_pl": "polski",
+}
+```
+
+Early versions of _Black_ used to ruthlessly collapse those into one line (it fits!).
+Now, you can communicate that you don't want that by putting a trailing comma in the
+collection yourself. When you do, _Black_ will know to always explode your collection
+into one item per line.
+
+How do you make it stop? Just delete that trailing comma and _Black_ will collapse your
+collection into one line if it fits.
+
+### r"strings" and R"strings"
+
+_Black_ normalizes string quotes as well as string prefixes, making them lowercase. One
+exception to this rule is r-strings. It turns out that the very popular
+[MagicPython](https://github.com/MagicStack/MagicPython/) syntax highlighter, used by
+default by (among others) GitHub and Visual Studio Code, differentiates between
+r-strings and R-strings. The former are syntax highlighted as regular expressions while
+the latter are treated as true raw strings with no special semantics.
+
## pyproject.toml
_Black_ is able to read project-specific default values for its command line options
### Emacs
-Use [proofit404/blacken](https://github.com/proofit404/blacken) or
-[Elpy](https://github.com/jorgenschaefer/elpy).
+Options include the following:
+
+- [purcell/reformatter.el](https://github.com/purcell/reformatter.el)
+- [proofit404/blacken](https://github.com/proofit404/blacken)
+- [Elpy](https://github.com/jorgenschaefer/elpy).
### PyCharm/IntelliJ IDEA
%LocalAppData%\Programs\Python\Python36-32\Scripts\black.exe # possible location
```
+Note that if you are using a virtual environment detected by PyCharm, this is an
+unneeded step. In this case the path to `black` is `$PyInterpreterDirectory$/black`.
+
3. Open External tools in PyCharm/IntelliJ IDEA
On macOS:
6. Optionally, run _Black_ on every file save:
1. Make sure you have the
- [File Watcher](https://plugins.jetbrains.com/plugin/7177-file-watchers) plugin
+ [File Watchers](https://plugins.jetbrains.com/plugin/7177-file-watchers) plugin
installed.
2. Go to `Preferences or Settings -> Tools -> File Watchers` and click `+` to add a
new watcher:
- Output paths to refresh: `$FilePath$`
- Working directory: `$ProjectFileDir$`
- - Uncheck "Auto-save edited files to trigger the watcher"
+ - Uncheck "Auto-save edited files to trigger the watcher" in Advanced Options
### Wing IDE
To install with [vim-plug](https://github.com/junegunn/vim-plug):
```
-Plug 'psf/black'
+Plug 'psf/black', { 'branch': 'stable' }
```
or with [Vundle](https://github.com/VundleVim/Vundle.vim):
Plugin 'psf/black'
```
+and execute the following in a terminal:
+
+```console
+$ cd ~/.vim/bundle/black
+$ git checkout origin/stable -b stable
+```
+
or you can copy the plugin from
-[plugin/black.vim](https://github.com/psf/black/tree/master/plugin/black.vim).
+[plugin/black.vim](https://github.com/psf/black/blob/stable/plugin/black.vim).
```
mkdir -p ~/.vim/pack/python/start/black/plugin
```
**How to get Vim with Python 3.6?** On Ubuntu 17.10 Vim comes with Python 3.6 by
-default. On macOS with Homebrew run: `brew install vim --with-python3`. When building
-Vim from source, use: `./configure --enable-python3interp=yes`. There's many guides
-online how to do this.
+default. On macOS with Homebrew run: `brew install vim`. When building Vim from source,
+use: `./configure --enable-python3interp=yes`. There's many guides online how to do
+this.
+
+**I get an import error when using _Black_ from a virtual environment**: If you get an
+error message like this:
+
+```text
+Traceback (most recent call last):
+ File "<string>", line 63, in <module>
+ File "/home/gui/.vim/black/lib/python3.7/site-packages/black.py", line 45, in <module>
+ from typed_ast import ast3, ast27
+ File "/home/gui/.vim/black/lib/python3.7/site-packages/typed_ast/ast3.py", line 40, in <module>
+ from typed_ast import _ast3
+ImportError: /home/gui/.vim/black/lib/python3.7/site-packages/typed_ast/_ast3.cpython-37m-x86_64-linux-gnu.so: undefined symbool: PyExc_KeyboardInterrupt
+```
+
+Then you need to install `typed_ast` and `regex` directly from the source code. The
+error happens because `pip` will download [Python wheels](https://pythonwheels.com/) if
+they are available. Python wheels are a new standard of distributing Python packages and
+packages that have Cython and extensions written in C are already compiled, so the
+installation is much more faster. The problem here is that somehow the Python
+environment inside Vim does not match with those already compiled C extensions and these
+kind of errors are the result. Luckily there is an easy fix: installing the packages
+from the source code.
+
+The two packages that cause the problem are:
+
+- [regex](https://pypi.org/project/regex/)
+- [typed-ast](https://pypi.org/project/typed-ast/)
+
+Now remove those two packages:
+
+```console
+$ pip uninstall regex typed-ast -y
+```
+
+And now you can install them with:
+
+```console
+$ pip install --no-binary :all: regex typed-ast
+```
+
+The C extensions will be compiled and now Vim's Python environment will match. Note that
+you need to have the GCC compiler and the Python development files installed (on
+Ubuntu/Debian do `sudo apt-get install build-essential python3-dev`).
+
+If you later want to update _Black_, you should do it like this:
+
+```console
+$ pip install -U black --no-binary regex,typed-ast
+```
### Visual Studio Code
### Kakoune
-Add the following hook to your kakrc, then run black with `:format`.
+Add the following hook to your kakrc, then run _Black_ with `:format`.
```
hook global WinSetOption filetype=python %{
}
```
+### Thonny
+
+Use [Thonny-black-code-format](https://github.com/Franccisco/thonny-black-code-format).
+
### Other editors
Other editors will require external contributions.
There is no official blackd client tool (yet!). You can test that blackd is working
using `curl`:
-```
+```sh
blackd --bind-port 9090 & # or let blackd choose a port
curl -s -XPOST "localhost:9090" -d "print('valid')"
```
The headers controlling how code is formatted are:
-If any of these headers are set to invalid values, `blackd` returns a `HTTP 400` error
-response, mentioning the name of the problematic header in the message body.
-
- `X-Line-Length`: corresponds to the `--line-length` command line flag.
- `X-Skip-String-Normalization`: corresponds to the `--skip-string-normalization`
command line flag. If present and its value is not the empty string, no string
The response headers include a `X-Black-Version` header containing the version of
_Black_.
+## black-primer
+
+`black-primer` is a tool built for CI (and huumans) to have _Black_ `--check` a number
+of (configured in `primer.json`) Git accessible projects in parallel. _(A PR will be
+accepted to add Mercurial support.)_
+
+### Run flow
+
+- Ensure we have a `black` + `git` in PATH
+- Load projects from `primer.json`
+- Run projects in parallel with `--worker` workers (defaults to CPU count / 2)
+ - Checkout projects
+ - Run black and record result
+ - Clean up repository checkout _(can optionally be disabled via `--keep`)_
+- Display results summary to screen
+- Default to cleaning up `--work-dir` (which defaults to tempfile schemantics)
+- Return
+ - 0 for successful run
+ - < 0 for environment / internal error
+ - > 0 for each project with an error
+
+### Speed up Runs 🏎
+
+If you're running locally yourself to test black on lots of code try:
+
+- Using `-k` / `--keep` + `-w` / `--work-dir` so you don't have to re-checkout the repo
+ each run
+
+### CLI Arguments
+
+```text
+Usage: black-primer [OPTIONS]
+
+ primer - prime projects for blackening... 🏴
+
+Options:
+ -c, --config PATH JSON config file path [default: /Users/cooper/repos/
+ black/src/black_primer/primer.json]
+
+ --debug Turn on debug logging [default: False]
+ -k, --keep Keep workdir + repos post run [default: False]
+ -L, --long-checkouts Pull big projects to test [default: False]
+ -R, --rebase Rebase project if already checked out [default:
+ False]
+
+ -w, --workdir PATH Directory Path for repo checkouts [default: /var/fol
+ ders/tc/hbwxh76j1hn6gqjd2n2sjn4j9k1glp/T/primer.20200
+ 517125229]
+
+ -W, --workers INTEGER Number of parallel worker coroutines [default: 69]
+ -h, --help Show this message and exit.
+```
+
+### primer config file
+
+The config is JSON format. Its main element is the `"projects"` dictionary. Below
+explains each parameter:
+
+```json
+{
+ "projects": {
+ "00_Example": {
+ "cli_arguments": "List of extra CLI arguments to pass Black for this project",
+ "expect_formatting_changes": "Boolean to indicate that the version of Black is expected to cause changes",
+ "git_clone_url": "URL you would pass `git clone` to check out this repo",
+ "long_checkout": "Boolean to have repo skipped by defauult unless `--long-checkouts` is specified",
+ "py_versions": "List of major Python versions to run this project with - all will do as you'd expect - run on ALL versions"
+ },
+ "aioexabgp": {
+ "cli_arguments": [],
+ "expect_formatting_changes": true,
+ "git_clone_url": "https://github.com/cooperlees/aioexabgp.git",
+ "long_checkout": false,
+ "py_versions": ["all", "3.8"] // "all" ignores all other versions
+ }
+ }
+}
+```
+
+### Example run
+
+```console
+cooper-mbp:black cooper$ ~/venvs/b/bin/black-primer
+[2020-05-17 13:06:40,830] INFO: 4 projects to run Black over (lib.py:270)
+[2020-05-17 13:06:44,215] INFO: Analyzing results (lib.py:285)
+-- primer results 📊 --
+
+3 / 4 succeeded (75.0%) ✅
+1 / 4 FAILED (25.0%) 💩
+ - 0 projects disabled by config
+ - 0 projects skipped due to Python version
+ - 0 skipped due to long checkout
+
+Failed projects:
+
+### flake8-bugbear:
+ - Returned 1
+ - stdout:
+--- tests/b303_b304.py 2020-05-17 20:04:09.991227 +0000
++++ tests/b303_b304.py 2020-05-17 20:06:42.753851 +0000
+@@ -26,11 +26,11 @@
+ maxint = 5 # this is okay
+ # the following shouldn't crash
+ (a, b, c) = list(range(3))
+ # it's different than this
+ a, b, c = list(range(3))
+- a, b, c, = list(range(3))
++ a, b, c = list(range(3))
+ # and different than this
+ (a, b), c = list(range(3))
+ a, *b, c = [1, 2, 3, 4, 5]
+ b[1:3] = [0, 0]
+
+would reformat tests/b303_b304.py
+Oh no! 💥 💔 💥
+1 file would be reformatted, 22 files would be left unchanged.
+```
+
## Version control integration
Use [pre-commit](https://pre-commit.com/). Once you
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](/pyproject.toml) for an example.
+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 tag that is pinned to the latest release on PyPI. If you'd rather run on
+`stable` is a branch that tracks the latest release on PyPI. If you'd rather run on
master, this is also an option.
## Ignoring unmodified files
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, Pipenv, virtualenv), pandas, Pillow, every Datadog
-Agent Integration.
+Poetry, PyPA applications (Warehouse, Bandersnatch, Pipenv, virtualenv), pandas, Pillow,
+every Datadog Agent Integration, Home Assistant.
+
+The following organizations use _Black_: Facebook, Dropbox.
Are we missing anyone? Let us know.
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](CONTRIBUTING.md).
+More details can be found in
+[CONTRIBUTING](https://github.com/psf/black/blob/master/CONTRIBUTING.md).
## Change Log
-### 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://pythonhosted.org/spyder/) 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
+The log's become rather long. It moved to its own file.
-- date-versioned (see: https://calver.org/)
+See [CHANGES](https://github.com/psf/black/blob/master/CHANGES.md).
## Authors
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), and
-[Zsolt Dollenstein](mailto:zsol.zsol@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:cryptolabour@gmail.com)
+- [Abdur-Rahmaan Janhangeer](mailto:arj.python@gmail.com)
- [Adam Johnson](mailto:me@adamj.eu)
- [Alexander Huynh](mailto:github@grande.coffee)
- [Andrew Thorp](mailto:andrew.thorp.dev@gmail.com)
- Charles Reid
- [Christian Heimes](mailto:christian@python.org)
- [Chuck Wooters](mailto:chuck.wooters@microsoft.com)
+- [Cooper Ry Lees](mailto:me@cooperlees.com)
- [Daniel Hahler](mailto:github@thequod.de)
- [Daniel M. Capella](mailto:polycitizen@gmail.com)
- Daniele Esposti