chore(deps): update dependency black to v26

[renovate-bot]

This PR contains the following updates:

Package	Change	Age	Confidence
black (changelog)	==24.10.0 → ==26.1.0
black (changelog)	==24.8.0 → ==26.1.0

---

Release Notes

psf/black (black)

v26.1.0

Compare Source

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

Compare Source

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

Compare Source

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

Compare Source

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

Compare Source

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)

---

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---

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[gemini-code-assist]

Summary of Changes

Hello @renovate-bot, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request updates the black code formatter dependency to version 26.1.0. This upgrade brings the latest formatting standards, including the new 2026 stable style, and adjusts Python version compatibility by dropping support for Python 3.9 while adding support for Python 3.14. The primary impact will be a reformatting of Python code to align with Black's updated style guidelines.

Highlights

• Black Version Update: The black dependency has been updated from v24.8.0 or v24.10.0 to v26.1.0, incorporating multiple minor and major releases.
• New Stable Style (2026): This update introduces the 2026 stable style, bringing several new formatting rules, such as always forcing one blank line after import statements and more compact handling of multiline strings.
• Python Version Compatibility: Black no longer supports Python 3.9, while simultaneously adding support for Python 3.14 and its new t-string syntax.
• Formatting Improvements: Improvements include fixing # fmt: skip behavior on one-liners, removing unnecessary parentheses from assignment left-hand sides, and standardizing type comments.

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[gemini-code-assist]

Code Review

This pull request updates the black dependency to version 26.1.0. While updating dependencies is good practice, this change introduces a critical issue. The new version of black requires Python 3.9+, but it's being applied to environments with Python versions older than 3.9, which will cause installation failures. My review includes a suggestion to use a compatible version of black for older Python environments to resolve this issue.

[gemini-code-assist]

This update is incorrect and will break the build for older Python versions. black version 26.1.0 requires Python 3.9 or newer. However, the changes apply this version to environments where python_version < "3.9" (e.g., Python 3.8), which will cause dependency installation to fail.

To fix this, you should continue to use a version of black that supports older Python versions for those environments. The latest version of black that supports Python 3.8 is 24.10.0.

black==24.10.0; python_version < "3.9"
black==26.1.0; python_version >= "3.9"