v26.3.1

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Stable style

• Prevent Jupyter notebook magic masking collisions from corrupting cells by using
  exact-length placeholders for short magics and aborting if a placeholder can no longer
  be unmasked safely (#​5038)

Configuration

• Always hash cache filename components derived from --python-cell-magics so custom
  magic names cannot affect cache paths (#​5038)

Blackd

• Disable browser-originated requests by default, add configurable origin allowlisting
  and request body limits, and bound executor submissions to improve backpressure
  (#​5039)

v26.3.0

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Stable style

• Don't double-decode input, causing non-UTF-8 files to be corrupted (#​4964)
• Fix crash on standalone comment in lambda default arguments (#​4993)
• Preserve parentheses when # type: ignore comments would be merged with other
  comments on the same line, preventing AST equivalence failures (#​4888)

Preview style

• Fix bug where if guards in case blocks were incorrectly split when the pattern had
  a trailing comma (#​4884)
• Fix string_processing crashing on unassigned long string literals with trailing
  commas (one-item tuples) (#​4929)
• Simplify implementation of the power operator "hugging" logic (#​4918)

Packaging

• Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in
  frozen environments (#​4930)

Performance

• Introduce winloop for windows as an alternative to uvloop (#​4996)
• Remove deprecated function uvloop.install() in favor of uvloop.new_event_loop()
  (#​4996)
• Rename maybe_install_uvloop function to maybe_use_uvloop to simplify loop
  installation and creation of either a uvloop/winloop evenloop or default eventloop
  (#​4996)

Output

• Emit a clear warning when the target Python version is newer than the running Python
  version, since AST safety checks cannot parse newer syntax. Also replace the
  misleading "INTERNAL ERROR" message with an actionable error explaining the version
  mismatch (#​4983)

Blackd

• Introduce winloop to be used when windows in use which enables blackd to run faster on
  windows when winloop is installed. (#​4996)

Integrations

• Remove unused gallery script (#​5030)
• Harden parsing of black requirements in the GitHub Action when use_pyproject is
  enabled so that only version specifiers are accepted and direct references such as
  black @​ https://... are rejected. Users should upgrade to the latest version of the
  action as soon as possible. This update is received automatically when using
  psf/black@stable, and is independent of the version of Black installed by the
  action. (#​5031)

Documentation

• Expand preview style documentation with detailed examples for wrap_comprehension_in,
  simplify_power_operator_hugging, and wrap_long_dict_values_in_parens features
  (#​4987)
• Add detailed documentation for formatting Jupyter Notebooks (#​5009)

v26.1.0

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Highlights

Introduces the 2026 stable style (#​4892), stabilizing the following changes:

• always_one_newline_after_import: Always force one blank line after import
  statements, except when the line after the import is a comment or an import statement
  (#​4489)
• fix_fmt_skip_in_one_liners: Fix # fmt: skip behavior on one-liner declarations,
  such as def foo(): return "mock" # fmt: skip, where previously the declaration would
  have been incorrectly collapsed (#​4800)
• fix_module_docstring_detection: Fix module docstrings being treated as normal
  strings if preceded by comments (#​4764)
• fix_type_expansion_split: Fix type expansions split in generic functions (#​4777)
• multiline_string_handling: Make expressions involving multiline strings more compact
  (#​1879)
• normalize_cr_newlines: Add \r style newlines to the potential newlines to
  normalize file newlines both from and to (#​4710)
• remove_parens_around_except_types: Remove parentheses around multiple exception
  types in except and except* without as (#​4720)
• remove_parens_from_assignment_lhs: Remove unnecessary parentheses from the left-hand
  side of assignments while preserving magic trailing commas and intentional multiline
  formatting (#​4865)
• standardize_type_comments: Format type comments which have zero or more spaces
  between # and type: or between type: and value to # type: (value) (#​4645)

The following change was not in any previous stable release:

• Regenerated the _width_table.py and added tests for the Khmer language (#​4253)

This release alo bumps pathspec to v1 and fixes inconsistencies with Git's
.gitignore logic (#​4958). Now, files will be ignored if a pattern matches them, even
if the parent directory is directly unignored. For example, Black would previously
format exclude/not_this/foo.py with this .gitignore:

exclude/
!exclude/not_this/

Now, exclude/not_this/foo.py will remain ignored. To ensure exclude/not_this/ and
all of it's children are included in formatting (and in Git), use this .gitignore:

*/exclude/*
!*/exclude/not_this/

This new behavior matches Git. The leading */ are only necessary if you wish to ignore
matching subdirectories (like the previous behavior did), and not just matching root
directories.

Output

• Explicitly shutdown the multiprocessing manager when run in diff mode too (#​4952)

Integrations

• Upgraded PyPI upload workflow to use Trusted Publishing (#​4611)

v25.12.0

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Highlights

• Black no longer supports running with Python 3.9 (#​4842)

Stable style

• Fix bug where comments preceding # fmt: off/# fmt: on blocks were incorrectly
  removed, particularly affecting Jupytext's # %% [markdown] comments (#​4845)
• Fix crash when multiple # fmt: skip comments are used in a multi-part if-clause, on
  string literals, or on dictionary entries with long lines (#​4872)
• Fix possible crash when fmt: directives aren't on the top level (#​4856)

Preview style

• Fix fmt: skip skipping the line after instead of the line it's on (#​4855)
• Remove unnecessary parentheses from the left-hand side of assignments while preserving
  magic trailing commas and intentional multiline formatting (#​4865)
• Fix fix_fmt_skip_in_one_liners crashing on with statements (#​4853)
• Fix fix_fmt_skip_in_one_liners crashing on annotated parameters (#​4854)
• Fix new lines being added after imports with # fmt: skip on them (#​4894)

Packaging

• Releases now include arm64 Windows binaries and wheels (#​4814)

Integrations

• Add output-file input to GitHub Action psf/black to write formatter output to a
  file for artifact capture and log cleanliness (#​4824)

v25.11.0

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Highlights

• Enable base 3.14 support (#​4804)
• Add support for the new Python 3.14 t-string syntax introduced by PEP 750 (#​4805)

Stable style

• Fix bug where comments between # fmt: off and # fmt: on were reformatted (#​4811)
• Comments containing fmt directives now preserve their exact formatting instead of
  being normalized (#​4811)

Preview style

• Move multiline_string_handling from --unstable to --preview (#​4760)
• Fix bug where module docstrings would be treated as normal strings if preceded by
  comments (#​4764)
• Fix bug where python 3.12 generics syntax split line happens weirdly (#​4777)
• Standardize type comments to form # type: <value> (#​4645)
• Fix fix_fmt_skip_in_one_liners preview feature to respect # fmt: skip for compound
  statements with semicolon-separated bodies (#​4800)

Configuration

• Add no_cache option to control caching behavior. (#​4803)

Packaging

• Releases now include arm64 Linux binaries (#​4773)

Output

• Write unchanged content to stdout when excluding formatting from stdin using pipes
  (#​4610)

Blackd

• Implemented BlackDClient. This simple python client allows to easily send formatting
  requests to blackd (#​4774)

Integrations

• Enable 3.14 base CI (#​4804)
• Enhance GitHub Action psf/black to support the required-version major-version-only
  "stability" format when using pyproject.toml (#​4770)
• Improve error message for vim plugin users. It now handles independently vim version
• Vim: Warn on unsupported Vim and Python versions independently (#​4772)
• Vim: Print the import paths when importing black fails (#​4675)
• Vim: Fix handling of virtualenvs that have a different Python version (#​4675)

v25.9.0

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Highlights

• Remove support for pre-python 3.7 await/async as soft keywords/variable names
  (#​4676)

Stable style

• Fix crash while formatting a long del statement containing tuples (#​4628)
• Fix crash while formatting expressions using the walrus operator in complex with
  statements (#​4630)
• Handle # fmt: skip followed by a comment at the end of file (#​4635)
• Fix crash when a tuple appears in the as clause of a with statement (#​4634)
• Fix crash when tuple is used as a context manager inside a with statement (#​4646)
• Fix crash when formatting a \ followed by a \r followed by a comment (#​4663)
• Fix crash on a \\r\n (#​4673)
• Fix crash on await ... (where ... is a literal Ellipsis) (#​4676)
• Fix crash on parenthesized expression inside a type parameter bound (#​4684)
• Fix crash when using line ranges excluding indented single line decorated items
  (#​4670)

Preview style

• Fix a bug where one-liner functions/conditionals marked with # fmt: skip would still
  be formatted (#​4552)
• Improve multiline_string_handling with ternaries and dictionaries (#​4657)
• Fix a bug where string_processing would not split f-strings directly after
  expressions (#​4680)
• Wrap the in clause of comprehensions across lines if necessary (#​4699)
• Remove parentheses around multiple exception types in except and except* without
  as. (#​4720)
• Add \r style newlines to the potential newlines to normalize file newlines both from
  and to (#​4710)

Parser

• Rewrite tokenizer to improve performance and compliance (#​4536)
• Fix bug where certain unusual expressions (e.g., lambdas) were not accepted in type
  parameter bounds and defaults. (#​4602)

Performance

• Avoid using an extra process when running with only one worker (#​4734)

Integrations

• Fix the version check in the vim file to reject Python 3.8 (#​4567)
• Enhance GitHub Action psf/black to read Black version from an additional section in
  pyproject.toml: [project.dependency-groups] (#​4606)
• Build gallery docker image with python3-slim and reduce image size (#​4686)

Documentation

• Add FAQ entry for windows emoji not displaying (#​4714)

v25.1.0

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Highlights

This release introduces the new 2025 stable style (#​4558), stabilizing the following
changes:

• Normalize casing of Unicode escape characters in strings to lowercase (#​2916)
• Fix inconsistencies in whether certain strings are detected as docstrings (#​4095)
• Consistently add trailing commas to typed function parameters (#​4164)
• Remove redundant parentheses in if guards for case blocks (#​4214)
• Add parentheses to if clauses in case blocks when the line is too long (#​4269)
• Whitespace before # fmt: skip comments is no longer normalized (#​4146)
• Fix line length computation for certain expressions that involve the power operator
  (#​4154)
• Check if there is a newline before the terminating quotes of a docstring (#​4185)
• Fix type annotation spacing between * and more complex type variable tuple (#​4440)

The following changes were not in any previous release:

• Remove parentheses around sole list items (#​4312)
• Generic function definitions are now formatted more elegantly: parameters are split
  over multiple lines first instead of type parameter definitions (#​4553)

Stable style

• Fix formatting cells in IPython notebooks with magic methods and starting or trailing
  empty lines (#​4484)
• Fix crash when formatting with statements containing tuple generators/unpacking
  (#​4538)

Preview style

• Fix/remove string merging changing f-string quotes on f-strings with internal quotes
  (#​4498)
• Collapse multiple empty lines after an import into one (#​4489)
• Prevent string_processing and wrap_long_dict_values_in_parens from removing
  parentheses around long dictionary values (#​4377)
• Move wrap_long_dict_values_in_parens from the unstable to preview style (#​4561)

Packaging

• Store license identifier inside the License-Expression metadata field, see
  PEP 639. (#​4479)

Performance

• Speed up the is_fstring_start function in Black's tokenizer (#​4541)

Integrations

• If using stdin with --stdin-filename set to a force excluded path, stdin won't be
  formatted. (#​4539)

v24.10.0

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Highlights

• Black is now officially tested with Python 3.13 and provides Python 3.13
  mypyc-compiled wheels. (#​4436) (#​4449)
• Black will issue an error when used with Python 3.12.5, due to an upstream memory
  safety issue in Python 3.12.5 that can cause Black's AST safety checks to fail. Please
  use Python 3.12.6 or Python 3.12.4 instead. (#​4447)
• Black no longer supports running with Python 3.8 (#​4452)

Stable style

• Fix crashes involving comments in parenthesised return types or X | Y style unions.
  (#​4453)
• Fix skipping Jupyter cells with unknown %% magic (#​4462)

Preview style

• Fix type annotation spacing between * and more complex type variable tuple (i.e. def fn(*args: *tuple[*Ts, T]) -> None: pass) (#​4440)

Caching

• Fix bug where the cache was shared between runs with and without --unstable (#​4466)

Packaging

• Upgrade version of mypyc used to 1.12 beta (#​4450) (#​4449)
• blackd now requires a newer version of aiohttp. (#​4451)

Output

• Added Python target version information on parse error (#​4378)
• Add information about Black version to internal error messages (#​4457)

v24.8.0

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Stable style

• Fix crash when # fmt: off is used before a closing parenthesis or bracket. (#​4363)

Packaging

• Packaging metadata updated: docs are explictly linked, the issue tracker is now also
  linked. This improves the PyPI listing for Black. (#​4345)

Parser

• Fix regression where Black failed to parse a multiline f-string containing another
  multiline string (#​4339)
• Fix regression where Black failed to parse an escaped single quote inside an f-string
  (#​4401)
• Fix bug with Black incorrectly parsing empty lines with a backslash (#​4343)
• Fix bugs with Black's tokenizer not handling \{ inside f-strings very well (#​4422)
• Fix incorrect line numbers in the tokenizer for certain tokens within f-strings
  (#​4423)

Performance

• Improve performance when a large directory is listed in .gitignore (#​4415)

Blackd

• Fix blackd (and all extras installs) for docker container (#​4357)

v24.4.2

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This is a bugfix release to fix two regressions in the new f-string parser introduced in
24.4.1.

Parser

• Fix regression where certain complex f-strings failed to parse (#​4332)

Performance

• Fix bad performance on certain complex string literals (#​4331)

v24.4.1

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Highlights

• Add support for the new Python 3.12 f-string syntax introduced by PEP 701 (#​3822)

Stable style

• Fix crash involving indented dummy functions containing newlines (#​4318)

Parser

• Add support for type parameter defaults, a new syntactic feature added to Python 3.13
  by PEP 696 (#​4327)

Integrations

• Github Action now works even when git archive is skipped (#​4313)

v24.4.0

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Stable style

• Fix unwanted crashes caused by AST equivalency check (#​4290)

Preview style

• if guards in case blocks are now wrapped in parentheses when the line is too long.
  (#​4269)
• Stop moving multiline strings to a new line unless inside brackets (#​4289)

Integrations

• Add a new option use_pyproject to the GitHub Action psf/black. This will read the
  Black version from pyproject.toml. (#​4294)

v24.3.0

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Highlights

This release is a milestone: it fixes Black's first CVE security vulnerability. If you
run Black on untrusted input, or if you habitually put thousands of leading tab
characters in your docstrings, you are strongly encouraged to upgrade immediately to fix
CVE-2024-21503.

This release also fixes a bug in Black's AST safety check that allowed Black to make
incorrect changes to certain f-strings that are valid in Python 3.12 and higher.

Stable style

• Don't move comments along with delimiters, which could cause crashes (#​4248)
• Strengthen AST safety check to catch more unsafe changes to strings. Previous versions
  of Black would incorrectly format the contents of certain unusual f-strings containing
  nested strings with the same quote type. Now, Black will crash on such strings until
  support for the new f-string syntax is implemented. (#​4270)
• Fix a bug where line-ranges exceeding the last code line would not work as expected
  (#​4273)

Performance

• Fix catastrophic performance on docstrings that contain large numbers of leading tab
  characters. This fixes
  CVE-2024-21503.
  (#​4278)

Documentation

• Note what happens when --check is used with --quiet (#​4236)

v24.2.0

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Stable style

• Fixed a bug where comments where mistakenly removed along with redundant parentheses
  (#​4218)

Preview style

• Move the hug_parens_with_braces_and_square_brackets feature to the unstable style
  due to an outstanding crash and proposed formatting tweaks (#​4198)
• Fixed a bug where base expressions caused inconsistent formatting of ** in tenary
  expression (#​4154)
• Checking for newline before adding one on docstring that is almost at the line limit
  (#​4185)
• Remove redundant parentheses in case statement if guards (#​4214).

Configuration

• Fix issue where Black would ignore input files in the presence of symlinks (#​4222)
• Black now ignores pyproject.toml that is missing a tool.black section when
  discovering project root and configuration. Since Black continues to use version
  control as an indicator of project root, this is expected to primarily change behavior
  for users in a monorepo setup (desirably). If you wish to preserve previous behavior,
  simply add an empty [tool.black] to the previously discovered pyproject.toml
  (#​4204)

Output

• Black will swallow any SyntaxWarnings or DeprecationWarnings produced by the ast
  module when performing equivalence checks (#​4189)

Integrations

• Add a JSONSchema and provide a validate-pyproject entry-point (#​4181)

v24.1.1

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Bugfix release to fix a bug that made Black unusable on certain file systems with strict
limits on path length.

Preview style

• Consistently add trailing comma on typed parameters (#​4164)

Configuration

• Shorten the length of the name of the cache file to fix crashes on file systems that
  do not support long paths (#​4176)

v24.1.0

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Highlights

This release introduces the new 2024 stable style (#​4106), stabilizing the following
changes:

• Add parentheses around if-else expressions (#​2278)
• Dummy class and function implementations consisting only of ... are formatted more
  compactly (#​3796)
• If an assignment statement is too long, we now prefer splitting on the right-hand side
  (#​3368)
• Hex codes in Unicode escape sequences are now standardized to lowercase (#​2916)
• Allow empty first lines at the beginning of most blocks (#​3967, #​4061)
• Add parentheses around long type annotations (#​3899)
• Enforce newline after module docstrings (#​3932, #​4028)
• Fix incorrect magic trailing comma handling in return types (#​3916)
• Remove blank lines before class docstrings (#​3692)
• Wrap multiple context managers in parentheses if combined in a single with statement
  (#​3489)
• Fix bug in line length calculations for power operations (#​3942)
• Add trailing commas to collection literals even if there's a comment after the last
  entry (#​3393)
• When using --skip-magic-trailing-comma or -C, trailing commas are stripped from
  subscript expressions with more than 1 element (#​3209)
• Add extra blank lines in stubs in a few cases (#​3564, #​3862)
• Accept raw strings as docstrings (#​3947)
• Split long lines in case blocks (#​4024)
• Stop removing spaces from walrus operators within subscripts (#​3823)
• Fix incorrect formatting of certain async statements (#​3609)
• Allow combining # fmt: skip with other comments (#​3959)

There are already a few improvements in the --preview style, which are slated for the
2025 stable style. Try them out and
share your feedback. In the past, the preview
style has included some features that we were not able to stabilize. This year, we're
adding a separate --unstable style for features with known problems. Now, the
--preview style only includes features that we actually expect to make it into next
year's stable style.

Stable style

Several bug fixes were made in features that are moved to the stable style in this
release:

• Fix comment handling when parenthesising conditional expressions (#​4134)
• Fix bug where spaces were not added around parenthesized walruses in subscripts,
  unlike other binary operators (#​4109)
• Remove empty lines before docstrings in async functions (#​4132)
• Address a missing case in the change to allow empty lines at the beginning of all
  blocks, except immediately before a docstring (#​4130)
• For stubs, fix logic to enforce empty line after nested classes with bodies (#​4141)

Preview style

• Add --unstable style, covering preview features that have known problems that would
  block them from going into the stable style. Also add the --enable-unstable-feature
  flag; for example, use
  --enable-unstable-feature hug_parens_with_braces_and_square_brackets to apply this
  preview feature throughout 2024, even if a later Black release downgrades the feature
  to unstable (#​4096)
• Format module docstrings the same as class and function docstrings (#​4095)
• Fix crash when using a walrus in a dictionary (#​4155)
• Fix unnecessary parentheses when wrapping long dicts (#​4135)
• Stop normalizing spaces before # fmt: skip comments (#​4146)

Configuration

• Print warning when configuration in pyproject.toml contains an invalid key (#​4165)
• Fix symlink handling, properly ignoring symlinks that point outside of root (#​4161)
• Fix cache mtime logic that resulted in false positive cache hits (#​4128)
• Remove the long-deprecated --experimental-string-processing flag. This feature can
  currently be enabled with --preview --enable-unstable-feature string_processing.
  (#​4096)

Integrations

• Revert the change to run Black's pre-commit integration only on specific git hooks
  (#​3940) for better compatibility with older versions of pre-commit (#​4137)

v23.12.1

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Packaging

• Fixed a bug that included dependencies from the d extra by default (#​4108)

v23.12.0

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Highlights

It's almost 2024, which means it's time for a new edition of Black's stable style!
Together with this release, we'll put out an alpha release 24.1a1 showcasing the draft
2024 stable style, which we'll finalize in the January release. Please try it out and
share your feedback.

This release (23.12.0) will still produce the 2023 style. Most but not all of the
changes in --preview mode will be in the 2024 stable style.

Stable style

• Fix bug where # fmt: off automatically dedents when used with the --line-ranges
  option, even when it is not within the specified line range. (#​4084)
• Fix feature detection for parenthesized context managers (#​4104)

Preview style

• Prefer more equal signs before a break when splitting chained assignments (#​4010)
• Standalone form feed characters at the module level are no longer removed (#​4021)
• Additional cases of immediately nested tuples, lists, and dictionaries are now
  indented less (#​4012)
• Allow empty lines at the beginning of all blocks, except immediately before a
  docstring (#​4060)
• Fix crash in preview mode when using a short --line-length (#​4086)
• Keep suites consisting of only an ellipsis on their own lines if they are not
  functions or class definitions (#​4066) (#​4103)

Configuration

• --line-ranges now skips Black's internal stability check in --safe mode. This
  avoids a crash on rare inputs that have many unformatted same-content lines. (#​4034)

Packaging

• Upgrade to mypy 1.7.1 (#​4049) (#​4069)
• Faster compiled wheels are now available for CPython 3.12 (#​4070)

Integrations

• Enable 3.12 CI (#​4035)
• Build docker images in parallel (#​4054)
• Build docker images with 3.12 (#​4055)

v23.11.0

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Highlights

• Support formatting ranges of lines with the new --line-ranges command-line option
  (#​4020)

Stable style

• Fix crash on formatting bytes strings that look like docstrings (#​4003)
• Fix crash when whitespace followed a backslash before newline in a docstring (#​4008)
• Fix standalone comments inside complex blocks crashing Black (#​4016)
• Fix crash on formatting code like await (a ** b) (#​3994)
• No longer treat leading f-strings as docstrings. This matches Python's behaviour and
  fixes a crash (#​4019)

Preview style

• Multiline dicts and lists that are the sole argument to a function are now indented
  less (#​3964)
• Multiline unpacked dicts and lists as the sole argument to a function are now also
  indented less (#​3992)
• In f-string debug expressions, quote types that are visible in the final string are
  now preserved (#​4005)
• Fix a bug where long case blocks were not split into multiple lines. Also enable
  general trailing comma rules on case blocks (#​4024)
• Keep requiring two empty lines between module-level docstring and first function or
  class definition (#​4028)
• Add support for single-line format skip with other comments on the same line (#​3959)

Configuration

• Consistently apply force exclusion logic before resolving symlinks (#​4015)
• Fix a bug in the matching of absolute path names in --include (#​3976)

Performance

• Fix mypyc builds on arm64 on macOS (#​4017)

Integrations

• Black's pre-commit integration will now run only on git hooks appropriate for a code
  formatter (#​3940)