Black Files

Highlights

This release fixes a security issue in Black's bundled GitHub Action. Repositories that use the action are encouraged to update to the latest version of Black immediately. This update is received automatically when using psf/black@stable, and is independent of the version of Black installed by the action.

When the GitHub Action reads version specifiers from tool.black.required-version, it now only accepts released versions of Black, as it already did for black requirements in dependency lists. Other values, such as URL references, are now rejected. This issue has been registered as GHSA-cg8m-r9f2-5wm2; a CVE identifier is pending.

Stable style

• Fix a long Jupyter notebook assignment magic (for example x = !ls -la) being wrapped in parentheses, which IPython can no longer run; such cells are now left unchanged (#5481)
• Keep repeated lines outside the selected --line-ranges unchanged (#5436)
• Fix --line-ranges formatting lines that follow a statement when formatting joins or re-indents that statement (#5484)
• Fix --line-ranges crashing with an internal error when an unselected statement has a # fmt: skip comment on the last line before a closing bracket (#5477)
• Prevent moving an encoding declaration (for example # -*- coding: latin-1 -*-) onto the first two lines of a file (#5487)
• Fix adding an extra trailing blank line inside a multi-line module docstring when its last line is near the line length limit (#5494)

Preview style

• Do not split short expressions on delimiters (such as binary operators, comparisons, or comprehensions) inside brackets when preceded by a standalone comment (#5455)
• Fix the unstable string_processing feature removing backslash-newline sequences from raw strings, which changed their value (#5482)
• Avoid adding unnecessary parentheses around unbreakable right-hand side expressions in assignments (such as annotated assignments or subscript targets) (#5473)
• Parenthesize expressions with parameter comments when they exceed the line length under --preview (#5442)
• Fix wrap_long_dict_values_in_parens dropping the parentheses around a right-hand side that contains a dictionary, leaving a line over the length limit (#5492)
• Fix the unstable string_processing feature adding a space after * or ** in a PEP 695 type parameter (* Ts = ...) when it splits a string in the parameter's default (#5504)
• Avoid unnecessary line splits of trailers (such as indexing/subscripts) when an earlier bracket split exceeds the line length only due to a trailing comment (#5498)

Configuration

• Add --cache-dir to configure the cache directory from the command line (#5433)
• Don't cache a file as formatted after formatting or checking it with --line-ranges, which made a later full black --check pass and black skip the unformatted lines (#5476)
• Respect a .gitignore that starts with a UTF-8 byte order mark. The mark became part of the first pattern, so that pattern never matched and Black formatted files that git ignores (#5497)

Performance

• Avoid quadratic runtime when splitting very long lines with many trailing bracket pairs (such as consecutive subscripts) (#5475)

Integrations

• Fix the GitHub Action crashing on dependency-group includes when use_pyproject is enabled (#5479)
• When the GitHub Action reads version specifiers from tool.black.required-version, it now only accepts released versions of Black, as it already did for black requirements in dependency lists. Other values, such as URL references, are now rejected. (#5510)