X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/73bd7038fbefdb1c6a61fa1edf16ff61613050a5..ea4e714b9a3b636afd8e81c5c5c916fcf8e6ed42:/README.md?ds=sidebyside diff --git a/README.md b/README.md index 76ae9cf..ed9f105 100644 --- a/README.md +++ b/README.md @@ -1,49 +1,46 @@ ![Black Logo](https://raw.githubusercontent.com/psf/black/master/docs/_static/logo2-readme.png) +

The Uncompromising Code Formatter

Build Status +Actions Status +Actions Status Documentation Status Coverage Status License: MIT -PyPI +PyPI Downloads +conda-forge Code style: black

> “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. -*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. +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. +_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. +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)** | -**[pyproject.toml](#pyprojecttoml)** | -**[Editor integration](#editor-integration)** | -**[blackd](#blackd)** | +_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)** | -**[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)** | +**[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)** --- @@ -52,554 +49,295 @@ Watch the [PyCon 2019 talk](https://youtu.be/esZLCuWs_2Y) to learn more. ### Installation -*Black* can be installed by running `pip install black`. It requires -Python 3.6.0+ to run but you can reformat Python 2 code with it, too. +_Black_ can be installed by running `pip install black`. It requires Python 3.6.2+ to +run. If you want to format Python 2 code as well, install with +`pip install black[python2]`. + +#### 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/psf/black` ### 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`: +_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] + + -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] - --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. + -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 + 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 + 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 + 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 + 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|_build|buck- - out|build|dist)/] - -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 PATH Read configuration from 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). - - -### NOTE: This is a beta product + later. [default: /(\.direnv|\.eggs|\.git|\. + hg|\.mypy_cache|\.nox|\.tox|\.venv|venv|\.sv + n|_build|buck-out|build|dist)/] -*Black* is already [successfully used](#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. + --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). -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``. + --force-exclude TEXT Like --exclude, but files and directories + matching this regex will be excluded even + when they are passed explicitly as + arguments. -## The *Black* code style + --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. -*Black* reformats entire files in place. It is not configurable. It -doesn't take previous formatting into account. 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. It also -recognizes [YAPF](https://github.com/google/yapf)'s block comments to -the same effect, as a courtesy for straddling code. + -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. -### How *Black* wraps lines + --version Show the version and exit. + --config FILE Read configuration from FILE path. + -h, --help Show this message and exit. +``` -*Black* ignores previous formatting and applies uniform horizontal -and vertical whitespace to your code. The rules for horizontal -whitespace can be summarized as: do whatever makes `pycodestyle` happy. -The coding style used by *Black* can be viewed as a strict subset of -PEP 8. +_Black_ is a well-behaved Unix-style command-line tool: -As for vertical whitespace, *Black* tries to render one full expression -or simple statement per line. If this fits the allotted line length, -great. -```py3 -# in: +- 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). -j = [1, - 2, - 3, -] +### Using _Black_ with other tools -# out: +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. -j = [1, 2, 3] -``` +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). -If not, *Black* will look at the contents of the first outer matching -brackets and put that in a separate indented line. -```py3 -# in: +### Migrating your code style without ruining git blame -ImportantClass.important_method(exc, limit, lookup_lines, capture_locals, extra_argument) +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. -# out: +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. -ImportantClass.important_method( - exc, limit, lookup_lines, capture_locals, extra_argument -) ``` - -If that still doesn't fit the bill, it will decompose the internal -expression further using the same rule, indenting matching brackets -every time. If the contents of the matching brackets pair are -comma-separated (like an argument list, or a dict literal, and so on) -then *Black* will first try to keep them on the same line with the -matching brackets. If that doesn't work, it will put all of them in -separate lines. -```py3 -# in: - -def very_important_function(template: str, *variables, file: os.PathLike, engine: str, header: bool = True, debug: bool = False): - """Applies `variables` to the `template` and writes to `file`.""" - with open(file, 'w') as f: - ... - -# out: - -def very_important_function( - template: str, - *variables, - file: os.PathLike, - engine: str, - header: bool = True, - debug: bool = False, -): - """Applies `variables` to the `template` and writes to `file`.""" - with open(file, "w") as f: - ... +# Migrate code style to Black +5b4ab991dede475d393e9d69ec388fd6bd949699 ``` -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 clear delimiter -between two distinct sections of the code that otherwise share the same -indentation level (like the arguments list and the docstring in the -example above). - -If a data structure literal (tuple, list, set, dict) or a line of "from" -imports cannot fit in the allotted length, it's always split into one -element per line. This minimizes diffs as well as enables readers of -code to find which commit introduced a particular entry. This also -makes *Black* compatible with [isort](https://pypi.org/p/isort/) with -the following configuration. +Afterwards, you can pass that file to `git blame` and see clean and meaningful blame +information. -
-A compatible `.isort.cfg` - -``` -[settings] -multi_line_output=3 -include_trailing_comma=True -force_grid_wrap=0 -use_parentheses=True -line_length=88 +```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) ``` -The equivalent command line is: -``` -$ isort --multi-line=3 --trailing-comma --force-grid-wrap=0 --use-parentheses --line-width=88 [ file.py ] -``` -
+You can even configure `git` to automatically ignore revisions listed in a file on every +call to `git blame`. -### Line length - -You probably noticed the peculiar default line length. *Black* defaults -to 88 characters per line, which happens to be 10% over 80. This number -was found to produce significantly shorter files than sticking with 80 -(the most popular), or even 79 (used by the standard library). In -general, [90-ish seems like the wise choice](https://youtu.be/wf-BqAjZb8M?t=260). - -If you're paid by the line of code you write, you can pass -`--line-length` with a lower number. *Black* will try to respect that. -However, sometimes it won't be able to without breaking other rules. In -those rare cases, auto-formatted code will exceed your allotted limit. - -You can also increase it, but remember that people with sight disabilities -find it harder to work with line lengths exceeding 100 characters. -It also adversely affects side-by-side diff review on typical screen -resolutions. Long lines also make it harder to present code neatly -in documentation or talk slides. - -If you're using Flake8, you can bump `max-line-length` to 88 and forget -about it. Alternatively, use [Bugbear](https://github.com/PyCQA/flake8-bugbear)'s -B950 warning instead of E501 and keep the max line length at 80 which -you are probably already using. You'd do it like this: -```ini -[flake8] -max-line-length = 80 -... -select = C,E,F,W,B,B950 -ignore = E501,W503,E203 +```console +$ git config blame.ignoreRevsFile .git-blame-ignore-revs ``` -You'll find *Black*'s own .flake8 config file is configured like this. -If you're curious about the reasoning behind B950, -[Bugbear's documentation](https://github.com/PyCQA/flake8-bugbear#opinionated-warnings) -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". +**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 -### Empty lines - -*Black* avoids spurious vertical whitespace. This is in the spirit of -PEP 8 which says that in-function vertical whitespace should only be -used sparingly. - -*Black* will allow single empty lines inside functions, and single and -double empty lines on module level left by the original editors, except -when they're within parenthesized expressions. Since such expressions -are always reformatted to fit minimal space, this whitespace is lost. - -It will also insert proper spacing before and after function definitions. -It's one line before and after inner functions and two lines before and -after module-level functions and classes. *Black* will not put empty -lines between function/class definitions and standalone comments that -immediately precede the given function/class. - -*Black* will enforce single empty lines between a class-level docstring -and the first following field or method. This conforms to -[PEP 257](https://www.python.org/dev/peps/pep-0257/#multi-line-docstrings). - -*Black* won't insert empty lines after function docstrings unless that -empty line is required due to an inner function starting immediately -after. - - -### Trailing commas - -*Black* will add trailing commas to expressions that are split -by comma where each element is on its own line. This includes function -signatures. +_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. -Unnecessary trailing commas are removed if an expression fits in one -line. This makes it 1% more likely that your line won't exceed the -allotted line length limit. Moreover, in this scenario, if you added -another argument to your call, you'd probably fit it in the same line -anyway. That doesn't make diffs any larger. +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`. -One exception to removing trailing commas is tuple expressions with -just one element. In this case *Black* won't touch the single trailing -comma as this would unexpectedly change the underlying data type. Note -that this is also the case when commas are used while indexing. This is -a tuple in disguise: ```numpy_array[3, ]```. - -One exception to adding trailing commas is function signatures -containing `*`, `*args`, or `**kwargs`. In this case a trailing comma -is only safe to use on Python 3.6. *Black* will detect if your file is -already 3.6+ only and use trailing commas in this situation. If you -wonder how it knows, it looks for f-strings and existing use of trailing -commas in function signatures that have stars in them. In other words, -if you'd like a trailing comma in this situation and *Black* didn't -recognize it was safe to do so, put it there manually and *Black* will -keep it. - - -### Strings - -*Black* prefers double quotes (`"` and `"""`) over single quotes (`'` -and `'''`). It will replace the latter with the former as long as it -does not result in more backslash escapes than before. - -*Black* also standardizes string prefixes, making them always lowercase. -On top of that, if your code is already Python 3.6+ only or it's using -the `unicode_literals` future import, *Black* will remove `u` from the -string prefix as it is meaningless in those scenarios. - -The main reason to standardize on a single form of quotes is aesthetics. -Having one kind of quotes everywhere reduces reader distraction. -It will also enable a future version of *Black* to merge consecutive -string literals that ended up on the same line (see -[#26](https://github.com/psf/black/issues/26) for details). - -Why settle on double quotes? They anticipate apostrophes in English -text. They match the docstring standard described in [PEP 257](https://www.python.org/dev/peps/pep-0257/#what-is-a-docstring). -An empty string in double quotes (`""`) is impossible to confuse with -a one double-quote regardless of fonts and syntax highlighting used. -On top of this, double quotes for strings are consistent with C which -Python interacts a lot with. - -On certain keyboard layouts like US English, typing single quotes is -a bit easier than double quotes. The latter requires use of the Shift -key. My recommendation here is to keep using whatever is faster to type -and let *Black* handle the transformation. - -If you are adopting *Black* in a large project with pre-existing string -conventions (like the popular ["single quotes for data, double quotes for -human-readable strings"](https://stackoverflow.com/a/56190)), you can -pass `--skip-string-normalization` on the command line. This is meant as -an adoption helper, avoid using this for new projects. - -### Numeric literals - -*Black* standardizes most numeric literals to use lowercase letters for the -syntactic parts and uppercase letters for the digits themselves: `0xAB` -instead of `0XAB` and `1e10` instead of `1E10`. Python 2 long literals are -styled as `2L` instead of `2l` to avoid confusion between `l` and `1`. - - -### Line breaks & binary operators - -*Black* will break a line before a binary operator when splitting a block -of code over multiple lines. This is so that *Black* is compliant with the -recent changes in the [PEP 8](https://www.python.org/dev/peps/pep-0008/#should-a-line-break-before-or-after-a-binary-operator) -style guide, which emphasizes that this approach improves readability. - -This behaviour may raise ``W503 line break before binary operator`` warnings in -style guide enforcement tools like Flake8. Since ``W503`` is not PEP 8 compliant, -you should tell Flake8 to ignore these warnings. - - -### Slices - -PEP 8 [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. - -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 Flake8 to ignore these warnings. - - -### Parentheses - -Some parentheses are optional in the Python grammar. Any expression can -be wrapped in a pair of parentheses to form an atom. There are a few -interesting cases: - -- `if (...):` -- `while (...):` -- `for (...) in (...):` -- `assert (...), (...)` -- `from X import (...)` -- assignments like: - - `target = (...)` - - `target: type = (...)` - - `some, *un, packing = (...)` - - `augmented += (...)` - -In those cases, parentheses are removed when the entire statement fits -in one line, or if the inner expression doesn't have any delimiters to -further split on. If there is only a single delimiter and the expression -starts or ends with a bracket, the parenthesis can also be successfully -omitted since the existing bracket pair will organize the expression -neatly anyway. Otherwise, the parentheses are added. - -Please note that *Black* does not add or remove any additional nested -parentheses that you might want to have for clarity or further -code organization. For example those parentheses are not going to be -removed: -```py3 -return not (this or that) -decision = (maybe.this() and values > 0) or (maybe.that() and values < 0) -``` +## 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`, or lines that ends with `# fmt: skip`. Pay +attention that `# 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). -### Call chains - -Some popular APIs, like ORMs, use call chaining. This API style is known -as a [fluent interface](https://en.wikipedia.org/wiki/Fluent_interface). -*Black* formats those by treating dots that follow a call or an indexing -operation like a very low priority delimiter. It's easier to show the -behavior than to explain it. Look at the example: -```py3 -def example(session): - result = ( - session.query(models.Customer.id) - .filter( - models.Customer.account_id == account_id, - models.Customer.email == email_address, - ) - .order_by(models.Customer.id.asc()) - .all() - ) -``` +Please refer to this document before submitting an issue. What seems like a bug might be +intended behaviour. +## Pragmatism -### Typing stub files - -PEP 484 describes the syntax for type hints in Python. One of the -use cases for typing is providing type annotations for modules which -cannot contain them directly (they might be written in C, or they might -be third-party, or their implementation may be overly dynamic, and so on). - -To solve this, [stub files with the `.pyi` file -extension](https://www.python.org/dev/peps/pep-0484/#stub-files) can be -used to describe typing information for an external module. Those stub -files omit the implementation of classes and functions they -describe, instead they only contain the structure of the file (listing -globals, functions, and classes with their members). The recommended -code style for those files is more terse than PEP 8: - -* prefer `...` on the same line as the class/function signature; -* avoid vertical whitespace between consecutive module-level functions, - names, or methods and fields within a single class; -* use a single blank line between top-level class definitions, or none - if the classes are very small. - -*Black* enforces the above rules. There are additional guidelines for -formatting `.pyi` file that are not enforced yet but might be in -a future version of the formatter: - -* all function bodies should be empty (contain `...` instead of the body); -* do not use docstrings; -* prefer `...` over `pass`; -* for arguments with a default, use `...` instead of the actual default; -* avoid using string literals in type annotations, stub files support - forward references natively (like Python 3.7 code with `from __future__ - import annotations`); -* use variable annotations instead of type comments, even for stubs that - target older versions of Python; -* for arguments that default to `None`, use `Optional[]` explicitly; -* use `float` instead of `Union[int, float]`. +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. +_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`/`--extend-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://poetry.eustace.io/) or -[Flit](https://flit.readthedocs.io/en/latest/) it can fully replace the -need for `setup.py` and `setup.cfg` files. +[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 -### 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. -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. -If you're formatting standard input, *Black* will look for configuration -starting from the current working directory. +You can use a "global" configuration, stored in a specific location in your home +directory. This will be used as a fallback configuration, that is, it will be used if +and only if _Black_ doesn't find any configuration as mentioned above. Depending on your +operating system, this configuration file should be stored as: -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. +- Windows: `~\.black` +- Unix-like (Linux, MacOS, etc.): `$XDG_CONFIG_HOME/black` (`~/.config/black` if the + `XDG_CONFIG_HOME` environment variable is not set) -If you're running with `--verbose`, you will see a blue message if -a file was found and used. +Note that these are paths to the TOML file itself (meaning that they shouldn't be named +as `pyproject.toml`), not directories where you store the configuration. Here, `~` +refers to the path to your home directory. On Windows, this will be something like +`C:\\Users\UserName`. -Please note `blackd` will not use `pyproject.toml` configuration. +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. +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. +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.
-Example `pyproject.toml` +Example pyproject.toml ```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 -) +extend-exclude = ''' +# A regex preceded with ^/ will apply only to files and directories +# in the root of the project. +^/foo.py # exclude a file named foo.py in the root of the project (in addition to the defaults) ''' ``` @@ -607,358 +345,137 @@ exclude = ''' ### 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. +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 -### Emacs - -Use [proofit404/blacken](https://github.com/proofit404/blacken) or -[Elpy](https://github.com/jorgenschaefer/elpy). - - -### PyCharm/IntelliJ IDEA - -1. Install `black`. - -```console -$ pip install black -``` - -2. Locate your `black` installation folder. - - On macOS / Linux / BSD: - -```console -$ which black -/usr/local/bin/black # possible location -``` - - On Windows: - -```console -$ where black -%LocalAppData%\Programs\Python\Python36-32\Scripts\black.exe # possible location -``` - -3. Open External tools in PyCharm/IntelliJ IDEA - - On macOS: - -```PyCharm -> Preferences -> Tools -> External Tools``` - - On Windows / Linux / BSD: - -```File -> Settings -> Tools -> External Tools``` - -4. Click the + icon to add a new external tool with the following values: - - Name: Black - - Description: Black is the uncompromising Python code formatter. - - Program: - - Arguments: `"$FilePath$"` - -5. Format the currently opened file by selecting `Tools -> External Tools -> black`. - - Alternatively, you can set a keyboard shortcut by navigating to `Preferences or Settings -> Keymap -> External Tools -> External Tools - Black`. - -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 installed. - 2. Go to `Preferences or Settings -> Tools -> File Watchers` and click `+` to add a new watcher: - - Name: Black - - File type: Python - - Scope: Project Files - - Program: - - Arguments: `$FilePath$` - - Output paths to refresh: `$FilePath$` - - Working directory: `$ProjectFileDir$` - - Uncheck "Auto-save edited files to trigger the watcher" - - - -### Wing IDE - -Wing supports black via the OS Commands tool, as explained in the Wing documentation on [pep8 formatting](https://wingware.com/doc/edit/pep8). The detailed procedure is: - -1. Install `black`. +_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). -```console -$ pip install black -``` - -2. Make sure it runs from the command line, e.g. - -```console -$ black --help -``` - -3. In Wing IDE, activate the **OS Commands** panel and define the command **black** to execute black on the currently selected file: - -- Use the Tools -> OS Commands menu selection -- click on **+** in **OS Commands** -> New: Command line.. - - Title: black - - Command Line: black %s - - I/O Encoding: Use Default - - Key Binding: F1 - - [x] Raise OS Commands when executed - - [x] Auto-save files before execution - - [x] Line mode - -4. Select a file in the editor and press **F1** , or whatever key binding you selected in step 3, to reformat the file. - -### Vim - -Commands and shortcuts: - -* `:Black` to format the entire file (ranges not supported); -* `:BlackUpgrade` to upgrade *Black* inside the virtualenv; -* `:BlackVersion` to get the current version of *Black* inside the - virtualenv. +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). -Configuration: -* `g:black_fast` (defaults to `0`) -* `g:black_linelength` (defaults to `88`) -* `g:black_skip_string_normalization` (defaults to `0`) -* `g:black_virtualenv` (defaults to `~/.vim/black`) - -To install with [vim-plug](https://github.com/junegunn/vim-plug): +## blackd -``` -Plug 'psf/black' -``` +`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. -or with [Vundle](https://github.com/VundleVim/Vundle.vim): +## black-primer -``` -Plugin 'psf/black' -``` +`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. -or you can copy the plugin from [plugin/black.vim](https://github.com/psf/black/tree/master/plugin/black.vim). -Let me know if this requires any changes to work with Vim 8's builtin -`packadd`, or Pathogen, and so on. +(A PR adding Mercurial support will be accepted.) -This plugin **requires Vim 7.0+ built with Python 3.6+ support**. It -needs Python 3.6 to be able to run *Black* inside the Vim process which -is much faster than calling an external command. - -On first run, the plugin creates its own virtualenv using the right -Python version and automatically installs *Black*. You can upgrade it later -by calling `:BlackUpgrade` and restarting Vim. - -If you need to do anything special to make your virtualenv work and -install *Black* (for example you want to run a version from master), -create a virtualenv manually and point `g:black_virtualenv` to it. -The plugin will use it. +## Version control integration -To run *Black* on save, add the following line to `.vimrc` or `init.vim`: +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+ ``` -autocmd BufWritePre *.py execute ':Black' -``` - -**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. - - -### Visual Studio Code - -Use the [Python extension](https://marketplace.visualstudio.com/items?itemName=ms-python.python) -([instructions](https://code.visualstudio.com/docs/python/editing#_formatting)). - - -### SublimeText 3 - -Use [sublack plugin](https://github.com/jgirardet/sublack). - - -### Jupyter Notebook Magic - -Use [blackcellmagic](https://github.com/csurfer/blackcellmagic). - - -### Python Language Server - -If your editor supports the [Language Server Protocol](https://langserver.org/) -(Atom, Sublime Text, Visual Studio Code and many more), you can use -the [Python Language Server](https://github.com/palantir/python-language-server) with the -[pyls-black](https://github.com/rupert/pyls-black) plugin. - - -### Atom/Nuclide - -Use [python-black](https://atom.io/packages/python-black). - - -### Other editors - -Other editors will require external contributions. - -Patches welcome! ✨ 🍰 ✨ -Any tool that can pipe code through *Black* using its stdio mode (just -[use `-` as the file name](https://www.tldp.org/LDP/abs/html/special-chars.html#DASHREF2)). -The formatted code will be returned on stdout (unless `--check` was -passed). *Black* will still emit messages on stderr but that shouldn't -affect your use case. - -This can be used for example with PyCharm's or IntelliJ's [File Watchers](https://www.jetbrains.com/help/pycharm/file-watchers.html). - -## 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. - -### Usage +Then run `pre-commit install` and you're ready to go. -`blackd` is not packaged alongside *Black* by default because it has additional -dependencies. You will need to do `pip install black[d]` to install it. +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. -You can start the server on the default port, binding only to the local interface -by running `blackd`. You will see a single line mentioning the server's version, -and the host and port it's listening on. `blackd` will then print an access log -similar to most web servers on standard output, merged with any exception traces -caused by invalid formatting requests. +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. -`blackd` provides even less options than *Black*. You can see them by running -`blackd --help`: +## GitHub Actions -```text -Usage: blackd [OPTIONS] +Create a file named `.github/workflows/black.yml` inside your repository with: -Options: - --bind-host TEXT Address to bind the server to. - --bind-port INTEGER Port to listen on - --version Show the version and exit. - -h, --help Show this message and exit. -``` - -There is no official blackd client tool (yet!). You can test that blackd is -working using `curl`: - -``` -blackd --bind-port 9090 & # or let blackd choose a port -curl -s -XPOST "localhost:9090" -d "print('valid')" -``` +```yaml +name: Lint -### Protocol - -`blackd` only accepts `POST` requests at the `/` path. The body of the request -should contain the python source code to be formatted, encoded -according to the `charset` field in the `Content-Type` request header. If no -`charset` is specified, `blackd` assumes `UTF-8`. - -There are a few HTTP headers that control how the source is formatted. These -correspond to command line flags for *Black*. There is one exception to this: -`X-Protocol-Version` which if present, should have the value `1`, otherwise the -request is rejected with `HTTP 501` (Not Implemented). - -The headers controlling how code is formatted are: - - - `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 - normalization will be performed. - - `X-Fast-Or-Safe`: if set to `fast`, `blackd` will act as *Black* does when - passed the `--fast` command line flag. - - `X-Python-Variant`: if set to `pyi`, `blackd` will act as *Black* does when - passed the `--pyi` command line flag. Otherwise, its value must correspond to - a Python version or a set of comma-separated Python versions, optionally - prefixed with `py`. For example, to request code that is compatible - with Python 3.5 and 3.6, set the header to `py3.5,py3.6`. - -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. - -Apart from the above, `blackd` can produce the following response codes: - - - `HTTP 204`: If the input is already well-formatted. The response body is - empty. - - `HTTP 200`: If formatting was needed on the input. The response body - contains the blackened Python code, and the `Content-Type` header is set - accordingly. - - `HTTP 400`: If the input contains a syntax error. Details of the error are - returned in the response body. - - `HTTP 500`: If there was any kind of error while trying to format the input. - The response body contains a textual representation of the error. - -The response headers include a `X-Black-Version` header containing the version -of *Black*. +on: [push, pull_request] -## 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: stable - hooks: - - id: black - language_version: python3.6 +jobs: + lint: + runs-on: ubuntu-latest + steps: + - uses: actions/checkout@v2 + - uses: actions/setup-python@v2 + - uses: psf/black@stable + with: + args: ". --check" ``` -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](/pyproject.toml) -for an example. +### Inputs -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 master, this is also an option. +#### `black_args` +**optional**: Black input arguments. Defaults to `. --check --diff`. ## Ignoring unmodified files -*Black* remembers files it has already formatted, unless the `--diff` flag is used or +_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: +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\\AppData\Local\black\black\Cache\\cache...pickle` -* macOS: `/Users//Library/Caches/black//cache...pickle` -* Linux: `/home//.cache/black//cache...pickle` +- Windows: + `C:\\Users\\AppData\Local\black\black\Cache\\cache...pickle` +- macOS: + `/Users//Library/Caches/black//cache...pickle` +- Linux: + `/home//.cache/black//cache...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//`. +`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//`. ## 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, Pipenv, virtualenv), -pandas, Pillow, every Datadog Agent Integration. +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, Zulip. -Are we missing anyone? Let us know. +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): +**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. +> _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: +**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! @@ -966,513 +483,53 @@ developer of Twisted and CPython: > At least the name is good. -**Kenneth Reitz**, creator of [`requests`](http://python-requests.org/) -and [`pipenv`](https://docs.pipenv.org/): +**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: -```markdown +```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) - +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_ -## 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](CONTRIBUTING.md). - - -## Change Log - -### unreleased - -* 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) - -* *Black* can now format async generators (#593) - -* *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) - -* removed unnecessary parentheses around `yield` expressions (#834) - -* added parentheses around long tuples in unpacking assignments (#832) - -* 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) +In terms of inspiration, _Black_ is about as configurable as _gofmt_. This is +deliberate. -* if *Black* puts parenthesis around a single expression, it moves comments - to the wrapped expression instead of after the brackets (#872) +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. -* *Black* is now able to format Python code that uses assignment expressions - (`:=` as described in PEP-572) (#935) +More details can be found in +[CONTRIBUTING](https://github.com/psf/black/blob/master/CONTRIBUTING.md). -* *Black* is now able to format Python code that uses positional-only - arguments (`/` as described in PEP-570) (#946) +## Change log -* `blackd` now returns the version of *Black* in the response headers (#1013) - - -### 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 - -* date-versioned (see: https://calver.org/) +The log's become rather long. It moved to its own file. +See [CHANGES](https://github.com/psf/black/blob/master/CHANGES.md). ## Authors @@ -1481,29 +538,181 @@ 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), 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: -* [Anthony Sottile](mailto:asottile@umich.edu) -* [Artem Malyshev](mailto:proofit404@gmail.com) -* [Benjamin Woodruff](mailto:github@benjam.info) -* [Christian Heimes](mailto:christian@python.org) -* [Daniel M. Capella](mailto:polycitizen@gmail.com) -* [Eli Treuherz](mailto:eli@treuherz.com) -* hauntsaninja -* Hugo van Kemenade -* [Ivan Katanić](mailto:ivan.katanic@gmail.com) -* [Jason Fried](mailto:me@jasonfried.info) -* [Jonas Obrist](mailto:ojiidotch@gmail.com) -* [Luka Sterbic](mailto:luka.sterbic@gmail.com) -* [Miguel Gaiowski](mailto:miggaiowski@gmail.com) -* [Miroslav Shubernetskiy](mailto:miroslav@miki725.com) -* [Neraste](mailto:neraste.herr10@gmail.com) -* [Osaetin Daniel](mailto:osaetindaniel@gmail.com) -* [Peter Bengtsson](mailto:mail@peterbe.com) -* [Stavros Korokithakis](mailto:hi@stavros.io) -* [Sunil Kapil](mailto:snlkapil@gmail.com) -* [Utsav Shah](mailto:ukshah2@illinois.edu) -* [Vishwas B Sharma](mailto:sharma.vishwas88@gmail.com) -* [Chuck Wooters](mailto:chuck.wooters@microsoft.com) + +- [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. 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