# Black 25.1.0

- Product: Black (https://whatsnew.fyi/product/black)
- Vendor: Python Software Foundation
- Date: 2025-01-29
- Version: 25.1.0
- Original notes: https://github.com/psf/black/releases/tag/25.1.0
- Permalink: https://whatsnew.fyi/product/black/releases/25.1.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **changed** — Normalize casing of Unicode escape characters in strings to lowercase
- **fixed** — Fix inconsistencies in whether certain strings are detected as docstrings
- **changed** — Consistently add trailing commas to typed function parameters
- **changed** — Remove redundant parentheses in if guards for case blocks
- **changed** — Add parentheses to if clauses in case blocks when the line is too long
- **changed** — Whitespace before # fmt: skip comments is no longer normalized
- **fixed** — Fix line length computation for certain expressions that involve the power operator
- **fixed** — Check if there is a newline before the terminating quotes of a docstring
- **fixed** — Fix type annotation spacing between * and more complex type variable tuple
- **changed** — Remove parentheses around sole list items
- **changed** — Generic function definitions are now formatted more elegantly with parameters split over multiple lines first instead of type parameter definitions
- **fixed** — Fix formatting cells in IPython notebooks with magic methods and starting or trailing empty lines
- **fixed** — Fix crash when formatting with statements containing tuple generators or unpacking
- **fixed** — Fix string merging changing f-string quotes on f-strings with internal quotes
- **changed** — Collapse multiple empty lines after an import into one
- **fixed** — Prevent string_processing and wrap_long_dict_values_in_parens from removing parentheses around long dictionary values
- **changed** — Move wrap_long_dict_values_in_parens from the unstable to preview style
- **changed** — Store license identifier inside the License-Expression metadata field
- **changed** — Speed up the is_fstring_start function in Black's tokenizer
- **changed** — If using stdin with --stdin-filename set to a force excluded path, stdin won't be formatted

###### 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](https://peps.python.org/pep-0639/). (#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)