23.10.0

Stable style

• Fix comments getting removed from inside parenthesized strings (#3909)

Preview style

• Fix long lines with power operators getting split before the line length (#3942)
• Long type hints are now wrapped in parentheses and properly indented when split across
  multiple lines (#3899)
• Magic trailing commas are now respected in return types. (#3916)
• Require one empty line after module-level docstrings. (#3932)
• Treat raw triple-quoted strings as docstrings (#3947)

Configuration

• Fix cache versioning logic when BLACK_CACHE_DIR is set (#3937)

Parser

• Fix bug where attributes named type were not acccepted inside match statements
  (#3950)
• Add support for PEP 695 type aliases containing lambdas and other unusual expressions
  (#3949)

Output

• Black no longer attempts to provide special errors for attempting to format Python 2
  code (#3933)
• Black will more consistently print stacktraces on internal errors in verbose mode
  (#3938)

Integrations

• The action output displayed in the job summary is now wrapped in Markdown (#3914)

23.9.1

23.9.1

Due to various issues, the previous release (23.9.0) did not include compiled mypyc
wheels, which make Black significantly faster. These issues have now been fixed, and
this release should come with compiled wheels once again.

There will be no wheels for Python 3.12 due to a bug in mypyc. We will provide 3.12
wheels in a future release as soon as the mypyc bug is fixed.

Packaging

• Upgrade to mypy 1.5.1 (#3864)

Performance

• Store raw tuples instead of NamedTuples in Black's cache, improving performance and
  decreasing the size of the cache (#3877)

23.9.0

23.9.0

Preview style

• More concise formatting for dummy implementations (#3796)
• In stub files, add a blank line between a statement with a body (e.g an
  if sys.version_info > (3, x):) and a function definition on the same level (#3862)
• Fix a bug whereby spaces were removed from walrus operators within subscript(#3823)

Configuration

• Black now applies exclusion and ignore logic before resolving symlinks (#3846)

Performance

• Avoid importing IPython if notebook cells do not contain magics (#3782)
• Improve caching by comparing file hashes as fallback for mtime and size (#3821)

Blackd

• Fix an issue in blackd with single character input (#3558)

Integrations

• Black now has an
  official pre-commit mirror. Swapping
  https://github.com/psf/black to https://github.com/psf/black-pre-commit-mirror in
  your .pre-commit-config.yaml will make Black about 2x faster (#3828)
• The .black.env folder specified by ENV_PATH will now be removed on the completion
  of the GitHub Action (#3759)

23.7.0

23.7.0

Highlights

• Runtime support for Python 3.7 has been removed. Formatting 3.7 code will still be
  supported until further notice (#3765)

Stable style

• Fix a bug where an illegal trailing comma was added to return type annotations using
  PEP 604 unions (#3735)
• Fix several bugs and crashes where comments in stub files were removed or mishandled
  under some circumstances (#3745)
• Fix a crash with multi-line magic comments like type: ignore within parentheses
  (#3740)
• Fix error in AST validation when Black removes trailing whitespace in a type comment
  (#3773)

Preview style

• Implicitly concatenated strings used as function args are no longer wrapped inside
  parentheses (#3640)
• Remove blank lines between a class definition and its docstring (#3692)

Configuration

• The --workers argument to Black can now be specified via the BLACK_NUM_WORKERS
  environment variable (#3743)
• .pytest_cache, .ruff_cache and .vscode are now excluded by default (#3691)
• Fix Black not honouring pyproject.toml settings when running --stdin-filename
  and the pyproject.toml found isn't in the current working directory (#3719)
• Black will now error if exclude and extend-exclude have invalid data types in
  pyproject.toml, instead of silently doing the wrong thing (#3764)

Packaging

• Upgrade mypyc from 0.991 to 1.3 (#3697)
• Remove patching of Click that mitigated errors on Python 3.6 with LANG=C (#3768)

Parser

• Add support for the new PEP 695 syntax in Python 3.12 (#3703)

Performance

• Speed up Black significantly when the cache is full (#3751)
• Avoid importing IPython in a case where we wouldn't need it (#3748)

Output

• Use aware UTC datetimes internally, avoids deprecation warning on Python 3.12 (#3728)
• Change verbose logging to exactly mirror Black's logic for source discovery (#3749)

Blackd

• The blackd argument parser now shows the default values for options in their help
  text (#3712)

Integrations

• Black is now tested with
  PYTHONWARNDEFAULTENCODING = 1
  (#3763)
• Update GitHub Action to display black output in the job summary (#3688)

Documentation

• Add a CITATION.cff file to the root of the repository, containing metadata on how to
  cite this software (#3723)
• Update the classes and exceptions documentation in Developer reference to match
  the latest code base (#3755)

23.3.0

Highlights

This release fixes a longstanding confusing behavior in Black's GitHub action, where the
version of the action did not determine the version of Black being run (issue #3382). In
addition, there is a small bug fix around imports and a number of improvements to the
preview style.

Please try out the
preview style
with black --preview and tell us your feedback. All changes in the preview style are
expected to become part of Black's stable style in January 2024.

Stable style

• Import lines with # fmt: skip and # fmt: off no longer have an extra blank line
  added when they are right after another import line (#3610)

Preview style

• Add trailing commas to collection literals even if there's a comment after the last
  entry (#3393)
• async def, async for, and async with statements are now formatted consistently
  compared to their non-async version. (#3609)
• with statements that contain two context managers will be consistently wrapped in
  parentheses (#3589)
• Let string splitters respect East Asian Width
  (#3445)
• Now long string literals can be split after East Asian commas and periods (、 U+3001
  IDEOGRAPHIC COMMA, 。 U+3002 IDEOGRAPHIC FULL STOP, & ， U+FF0C FULLWIDTH COMMA)
  besides before spaces (#3445)
• For stubs, enforce one blank line after a nested class with a body other than just
  ... (#3564)
• Improve handling of multiline strings by changing line split behavior (#1879)

Parser

• Added support for formatting files with invalid type comments (#3594)

Integrations

• Update GitHub Action to use the version of Black equivalent to action's version if
  version input is not specified (#3543)
• Fix missing Python binary path in autoload script for vim (#3508)

Documentation

• Document that only the most recent release is supported for security issues;
  vulnerabilities should be reported through Tidelift (#3612)

23.1.0

Highlights

This is the first release of 2023, and following our stability policy, it comes with a number of improvements to our stable style, notably improvements to empty line handling and the removal of redundant parentheses in several contexts.

There are also many changes to the preview style; try out black --preview and give us feedback to help us set the stable style for next year.

In addition to style changes, Black now automatically infers the supported Python versions from your pyproject.toml file, removing the need to set Black's target versions separately.

Stable style

• Introduce the 2023 stable style, which incorporates most aspects of last year's preview style (#3418). Specific changes:
  • Enforce empty lines before classes and functions with sticky leading comments (#3302) (22.12.0)
  • Reformat empty and whitespace-only files as either an empty file (if no newline is present) or as a single newline character (if a newline is present) (#3348) (22.12.0)
  • Correctly handle trailing commas that are inside a line's leading non-nested parens (#3370) (22.12.0)
  • --skip-string-normalization / -S now prevents docstring prefixes from being normalized as expected (#3168) (since 22.8.0)
  • When using --skip-magic-trailing-comma or -C, trailing commas are stripped from subscript expressions with more than 1 element (#3209) (22.8.0)
  • Fix a string merging/split issue when a comment is present in the middle of implicitly concatenated strings on its own line (#3227) (22.8.0)
  • Docstring quotes are no longer moved if it would violate the line length limit (#3044, #3430) (22.6.0)
  • Parentheses around return annotations are now managed (#2990) (22.6.0)
  • Remove unnecessary parentheses around awaited objects (#2991) (22.6.0)
  • Remove unnecessary parentheses in with statements (#2926) (22.6.0)
  • Remove trailing newlines after code block open (#3035) (22.6.0)
  • Code cell separators #%% are now standardised to # %% (#2919) (22.3.0)
  • Remove unnecessary parentheses from except statements (#2939) (22.3.0)
  • Remove unnecessary parentheses from tuple unpacking in for loops (#2945) (22.3.0)
  • Avoid magic-trailing-comma in single-element subscripts (#2942) (22.3.0)
• Fix a crash when a colon line is marked between # fmt: off and # fmt: on (#3439)

Preview style

• Format hex codes in unicode escape sequences in string literals (#2916)
• Add parentheses around if-else expressions (#2278)
• Improve performance on large expressions that contain many strings (#3467)
• Fix a crash in preview style with assert + parenthesized string (#3415)
• Fix crashes in preview style with walrus operators used in function return annotations and except clauses (#3423)
• Fix a crash in preview advanced string processing where mixed implicitly concatenated regular and f-strings start with an empty span (#3463)
• Fix a crash in preview advanced string processing where a standalone comment is placed before a dict's value (#3469)
• Fix an issue where extra empty lines are added when a decorator has # fmt: skip applied or there is a standalone comment between decorators (#3470)
• Do not put the closing quotes in a docstring on a separate line, even if the line is too long (#3430)
• Long values in dict literals are now wrapped in parentheses; correspondingly unnecessary parentheses around short values in dict literals are now removed; long string lambda values are now wrapped in parentheses (#3440)
• Fix two crashes in preview style involving edge cases with docstrings (#3451)
• Exclude string type annotations from improved string processing; fix crash when the return type annotation is stringified and spans across multiple lines (#3462)
• Wrap multiple context managers in parentheses when targeting Python 3.9+ (#3489)
• Fix several crashes in preview style with walrus operators used in with statements or tuples (#3473)
• Fix an invalid quote escaping bug in f-string expressions where it produced invalid code. Implicitly concatenated f-strings with different quotes can now be merged or quote-normalized by changing the quotes used in expressions. (#3509)
• Fix crash on await (yield) when Black is compiled with mypyc (#3533)

Configuration

• Black now tries to infer its --target-version from the project metadata specified in pyproject.toml (#3219)

Packaging

• Upgrade mypyc from 0.971 to 0.991 so mypycified Black can be built on armv7 (#3380)
  • This also fixes some crashes while using compiled Black with a debug build of CPython
• Drop specific support for the tomli requirement on 3.11 alpha releases, working around a bug that would cause the requirement not to be installed on any non-final Python releases (#3448)
• Black now depends on packaging version 22.0 or later. This is required for new functionality that needs to parse part of the project metadata (#3219)

Output

• Calling black --help multiple times will return the same help contents each time (#3516)
• Verbose logging now shows the values of pyproject.toml configuration variables (#3392)
• Fix false symlink detection messages in verbose output due to using an incorrect relative path to the project root (#3385)

Integrations

• Move 3.11 CI to normal flow now that all dependencies support 3.11 (#3446)
• Docker: Add new latest_prerelease tag automation to follow latest black alpha release on docker images (#3465)

Documentation

• Expand vim-plug installation instructions to offer more explicit options (#3468)

23.1a1

This release provides a preview of Black's 2023 stable style. Black's default formatting style includes the following changes:

• Enforce empty lines before classes and functions with sticky leading comments
  (#3302) (22.12.0)
• Reformat empty and whitespace-only files as either an empty file (if no newline is
  present) or as a single newline character (if a newline is present) (#3348)
  (22.12.0)
• Implicitly concatenated strings used as function args are now wrapped inside
  parentheses (#3307) (22.12.0)
• Correctly handle trailing commas that are inside a line's leading non-nested parens
  (#3370) (22.12.0)
• --skip-string-normalization / -S now prevents docstring prefixes from being
  normalized as expected (#3168) (since 22.8.0)
• When using --skip-magic-trailing-comma or -C, trailing commas are stripped from
  subscript expressions with more than 1 element (#3209) (22.8.0)
• Implicitly concatenated strings inside a list, set, or tuple are now wrapped inside
  parentheses (#3162) (22.8.0)
• Fix a string merging/split issue when a comment is present in the middle of
  implicitly concatenated strings on its own line (#3227) (22.8.0)
• Docstring quotes are no longer moved if it would violate the line length limit
  (#3044, #3430) (22.6.0)
• Parentheses around return annotations are now managed (#2990) (22.6.0)
• Remove unnecessary parentheses around awaited objects (#2991) (22.6.0)
• Remove unnecessary parentheses in with statements (#2926) (22.6.0)
• Remove trailing newlines after code block open (#3035) (22.6.0)
• Code cell separators #%% are now standardised to # %% (#2919) (22.3.0)
• Remove unnecessary parentheses from except statements (#2939) (22.3.0)
• Remove unnecessary parentheses from tuple unpacking in for loops (#2945) (22.3.0)
• Avoid magic-trailing-comma in single-element subscripts (#2942) (22.3.0)

Please try it out and give feedback here: #3407

A stable 23.1.0 release will follow in January 2023.

22.12.0

Preview style

• Enforce empty lines before classes and functions with sticky leading comments (#3302)
• Reformat empty and whitespace-only files as either an empty file (if no newline is
  present) or as a single newline character (if a newline is present) (#3348)
• Implicitly concatenated strings used as function args are now wrapped inside
  parentheses (#3307)
• Correctly handle trailing commas that are inside a line's leading non-nested parens
  (#3370)

Configuration

• Fix incorrectly applied .gitignore rules by considering the .gitignore location
  and the relative path to the target file (#3338)
• Fix incorrectly ignoring .gitignore presence when more than one source directory is
  specified (#3336)

Parser

• Parsing support has been added for walruses inside generator expression that are
  passed as function args (for example,
  any(match := my_re.match(text) for text in texts)) (#3327).

Integrations

• Vim plugin: Optionally allow using the system installation of Black via
  let g:black_use_virtualenv = 0(#3309)

22.10.0

22.10.0

Highlights

• Runtime support for Python 3.6 has been removed. Formatting 3.6 code will still be
  supported until further notice.

Stable style

• Fix a crash when # fmt: on is used on a different block level than # fmt: off
  (#3281)

Preview style

• Fix a crash when formatting some dicts with parenthesis-wrapped long string keys
  (#3262)

Configuration

• .ipynb_checkpoints directories are now excluded by default (#3293)
• Add --skip-source-first-line / -x option to ignore the first line of source code
  while formatting (#3299)

Packaging

• Executables made with PyInstaller will no longer crash when formatting several files
  at once on macOS. Native x86-64 executables for macOS are available once again.
  (#3275)
• Hatchling is now used as the build backend. This will not have any effect for users
  who install Black with its wheels from PyPI. (#3233)
• Faster compiled wheels are now available for CPython 3.11 (#3276)

Blackd

• Windows style (CRLF) newlines will be preserved (#3257).

Integrations

• Vim plugin: add flag (g:black_preview) to enable/disable the preview style (#3246)
• Update GitHub Action to support formatting of Jupyter Notebook files via a jupyter
  option (#3282)
• Update GitHub Action to support use of version specifiers (e.g. <23) for Black
  version (#3265)

22.8.0

Highlights

• Python 3.11 is now supported, except for blackd as aiohttp does not support 3.11 as of publishing (#3234)
• This is the last release that supports running Black on Python 3.6 (formatting 3.6 code will continue to be supported until further notice)
• Reword the stability policy to say that we may, in rare cases, make changes that affect code that was not previously formatted by Black (#3155)

Stable style

• Fix an infinite loop when using # fmt: on/off in the middle of an expression or code block (#3158)
• Fix incorrect handling of # fmt: skip on colon (:) lines (#3148)
• Comments are no longer deleted when a line had spaces removed around power operators (#2874)

Preview style

• Single-character closing docstring quotes are no longer moved to their own line as this is invalid. This was a bug introduced in version 22.6.0. (#3166)
• --skip-string-normalization / -S now prevents docstring prefixes from being normalized as expected (#3168)
• When using --skip-magic-trailing-comma or -C, trailing commas are stripped from subscript expressions with more than 1 element (#3209)
• Implicitly concatenated strings inside a list, set, or tuple are now wrapped inside parentheses (#3162)
• Fix a string merging/split issue when a comment is present in the middle of implicitly concatenated strings on its own line (#3227)

Blackd

• blackd now supports enabling the preview style via the X-Preview header (#3217)

Configuration

• Black now uses the presence of debug f-strings to detect target version (#3215)
• Fix misdetection of project root and verbose logging of sources in cases involving --stdin-filename (#3216)
• Immediate .gitignore files in source directories given on the command line are now also respected, previously only .gitignore files in the project root and automatically discovered directories were respected (#3237)

Documentation

• Recommend using BlackConnect in IntelliJ IDEs (#3150)

Integrations

• Vim plugin: prefix messages with Black: so it's clear they come from Black (#3194)
• Docker: changed to a /opt/venv installation + added to PATH to be available to non-root users (#3202)

Output

• Change from deprecated asyncio.get_event_loop() to create our event loop which removes DeprecationWarning (#3164)
• Remove logging from internal blib2to3 library since it regularly emits error logs about failed caching that can and should be ignored (#3193)

Parser

• Type comments are now included in the AST equivalence check consistently so accidental deletion raises an error. Though type comments can't be tracked when running on PyPy 3.7 due to standard library limitations. (#2874)

Performance

• Reduce Black's startup time when formatting a single file by 15-30% (#3211)

Full Changelog: 22.6.0...22.8.0

---

Thank you!

• @hauntsaninja for modernizing our type annotations and fixing a few bugs too
• @yilei for fixing our # fmt: off/on/skip code and continuing to improve the preview style, notably the (still) experimental string processing
• The many community contributions to the non-core parts of the project:
  • @tobast for improving the QOL of the Vim plugin by simply appending Black: to most emitted messages
  • @Mogost for adding preview style support to blackd (finally 🎉)
  • @n-borges for improving the Docker image
  • @ionite34 for removing a hack in the official Black GitHub Action's start up code
• @cooperlees for adding support for Python 3.11 and addressing DeprecationWarnings
• @graingert for adding PyPy 3.8 to our CI matrix so we know Black works in even more places
• @martinResearch for contributing a simple fix for such a silly and stupid .gitignore bug that we should've caught many moons ago
• @fabioz for contributing the original patch that reduced the start up overhead when formatting a single file by 15-30% (!)

... and everyone else who contributed documentation, tests, or other improvements to the Black project!

Finally congratulations to the first time contributors this time around!

• @dmerejkowsky made their first contribution in #3142
• @m-aciek made their first contribution in #3150
• @Panther-12 made their first contribution in #3167
• @onescriptkid made their first contribution in #3170
• @tobast made their first contribution in #3194
• @n-borges made their first contribution in #3202
• @Mogost made their first contribution in #3217
• @ionite34 made their first contribution in #3226
• @martinResearch made their first contribution in #3237