Fix `string_processing` error with unassigned long string literal with trailing comma by Ankitsinghsisodya · Pull Request #4929 · psf/black

Ankitsinghsisodya · 2025-12-30T01:47:23Z

Description

This PR fixes issue #4912 where string_processing would crash with an INTERNAL ERROR
when processing an unassigned long string literal with a trailing comma (creating a
one-item tuple).

The Problem: When a line contains only a long string literal followed by a trailing
comma (making it a one-item tuple) and is not inside brackets, StringSplitter would
split the string into multiple implicitly concatenated strings. This created multiple
expressions where only the last has the comma, breaking AST equivalence:

# Input
"A long string that exceeds line length...",

# Incorrect output (before fix)
'A long string that exceeds line length'
'continuation of the string...',  # Only this line has the comma!

The Fix:

StringSplitter.do_splitter_match() now detects the STRING + COMMA pattern (bare
one-item tuple not inside brackets) and returns an error, deferring to
StringParenWrapper
StringParenWrapper._trailing_comma_tuple_match() is a new method that matches this
specific pattern
The string is wrapped in parentheses before splitting, preserving the tuple
semantics:

# Correct output (after fix)
(
    "A long string that exceeds line length"
    " continuation of the string..."
),

Checklist - did you ...

Implement any code style changes under the --preview style, following the
stability policy? > Yes, string_processing is an unstable feature enabled via
--preview --enable-unstable-feature=string_processing
Add an entry in CHANGES.md if necessary? > Added under "Preview style" in the
Unreleased section
Add / update tests if necessary? > Added test case in
tests/data/cases/preview_long_strings.py
Add new / update outdated documentation? > No documentation changes needed - this
is a bugfix for existing functionality

Fixes #4912
closes #4917

…h trailing commas When a line contains only a long string literal followed by a trailing comma (making it a one-item tuple) and is not inside brackets, StringSplitter would split the string, creating multiple expressions where only the last has the comma. This broke AST equivalence. The fix: 1. StringSplitter now detects this pattern and defers to StringParenWrapper 2. StringParenWrapper wraps the string in parentheses before splitting Fixes psf#4912

for more information, see https://pre-commit.ci

github-actions · 2025-12-31T16:59:12Z

diff-shades results comparing this PR (ba52d5a) to main (1d233bb):

--preview style: no changes

--stable style: no changes

What is this? | Workflow run | diff-shades documentation

cobaltt7 · 2026-01-01T17:57:28Z

Everything looks good here, thanks! Will merge after the 2026 style is stabilized.

Copilot

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pmolodo · 2026-01-23T02:19:59Z

Awesome, thanks for the quick fix!

…h trailing comma (psf#4929) Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: cobalt <61329810+cobaltt7@users.noreply.github.com>

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [black](https://github.com/psf/black) ([changelog](https://github.com/psf/black/blob/main/CHANGES.md)) | `<26.1.1,>=26.1.0` → `<26.3.1,>=26.3.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/black/26.3.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/black/26.1.0/26.3.0?slim=true) | --- ### Release Notes <details> <summary>psf/black (black)</summary> ### [`v26.3.0`](https://github.com/psf/black/blob/HEAD/CHANGES.md#2630) [Compare Source](psf/black@26.1.0...26.3.0) ##### Stable style - Don't double-decode input, causing non-UTF-8 files to be corrupted ([#4964](psf/black#4964)) - Fix crash on standalone comment in lambda default arguments ([#4993](psf/black#4993)) - Preserve parentheses when `# type: ignore` comments would be merged with other comments on the same line, preventing AST equivalence failures ([#4888](psf/black#4888)) ##### Preview style - Fix bug where `if` guards in `case` blocks were incorrectly split when the pattern had a trailing comma ([#4884](psf/black#4884)) - Fix `string_processing` crashing on unassigned long string literals with trailing commas (one-item tuples) ([#4929](psf/black#4929)) - Simplify implementation of the power operator "hugging" logic ([#4918](psf/black#4918)) ##### Packaging - Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments ([#4930](psf/black#4930)) ##### Performance - Introduce winloop for windows as an alternative to uvloop ([#4996](psf/black#4996)) - Remove deprecated function `uvloop.install()` in favor of `uvloop.new_event_loop()` ([#4996](psf/black#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](psf/black#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](psf/black#4983)) ##### *Blackd* - Introduce winloop to be used when windows in use which enables blackd to run faster on windows when winloop is installed. ([#4996](psf/black#4996)) ##### Integrations - Remove unused gallery script ([#5030](psf/black#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](psf/black#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](psf/black#4987)) - Add detailed documentation for formatting Jupyter Notebooks ([#5009](psf/black#5009)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/webexmemebot/pulls/571 Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [black](https://github.com/psf/black) ([changelog](https://github.com/psf/black/blob/main/CHANGES.md)) | `<26.1.1,>=26.1.0` → `<26.3.1,>=26.3.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/black/26.3.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/black/26.1.0/26.3.0?slim=true) | --- ### Release Notes <details> <summary>psf/black (black)</summary> ### [`v26.3.0`](https://github.com/psf/black/blob/HEAD/CHANGES.md#2630) [Compare Source](psf/black@26.1.0...26.3.0) ##### Stable style - Don't double-decode input, causing non-UTF-8 files to be corrupted ([#4964](psf/black#4964)) - Fix crash on standalone comment in lambda default arguments ([#4993](psf/black#4993)) - Preserve parentheses when `# type: ignore` comments would be merged with other comments on the same line, preventing AST equivalence failures ([#4888](psf/black#4888)) ##### Preview style - Fix bug where `if` guards in `case` blocks were incorrectly split when the pattern had a trailing comma ([#4884](psf/black#4884)) - Fix `string_processing` crashing on unassigned long string literals with trailing commas (one-item tuples) ([#4929](psf/black#4929)) - Simplify implementation of the power operator "hugging" logic ([#4918](psf/black#4918)) ##### Packaging - Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments ([#4930](psf/black#4930)) ##### Performance - Introduce winloop for windows as an alternative to uvloop ([#4996](psf/black#4996)) - Remove deprecated function `uvloop.install()` in favor of `uvloop.new_event_loop()` ([#4996](psf/black#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](psf/black#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](psf/black#4983)) ##### *Blackd* - Introduce winloop to be used when windows in use which enables blackd to run faster on windows when winloop is installed. ([#4996](psf/black#4996)) ##### Integrations - Remove unused gallery script ([#5030](psf/black#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](psf/black#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](psf/black#4987)) - Add detailed documentation for formatting Jupyter Notebooks ([#5009](psf/black#5009)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/pypilot/pulls/421 Reviewed-by: Luke Tainton <luke@tainton.uk> Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [black](https://github.com/psf/black) ([changelog](https://github.com/psf/black/blob/main/CHANGES.md)) | `<26.1.1,>=26.1.0` → `<26.3.1,>=26.3.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/black/26.3.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/black/26.1.0/26.3.0?slim=true) | --- ### Release Notes <details> <summary>psf/black (black)</summary> ### [`v26.3.0`](https://github.com/psf/black/blob/HEAD/CHANGES.md#2630) [Compare Source](psf/black@26.1.0...26.3.0) ##### Stable style - Don't double-decode input, causing non-UTF-8 files to be corrupted ([#4964](psf/black#4964)) - Fix crash on standalone comment in lambda default arguments ([#4993](psf/black#4993)) - Preserve parentheses when `# type: ignore` comments would be merged with other comments on the same line, preventing AST equivalence failures ([#4888](psf/black#4888)) ##### Preview style - Fix bug where `if` guards in `case` blocks were incorrectly split when the pattern had a trailing comma ([#4884](psf/black#4884)) - Fix `string_processing` crashing on unassigned long string literals with trailing commas (one-item tuples) ([#4929](psf/black#4929)) - Simplify implementation of the power operator "hugging" logic ([#4918](psf/black#4918)) ##### Packaging - Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments ([#4930](psf/black#4930)) ##### Performance - Introduce winloop for windows as an alternative to uvloop ([#4996](psf/black#4996)) - Remove deprecated function `uvloop.install()` in favor of `uvloop.new_event_loop()` ([#4996](psf/black#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](psf/black#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](psf/black#4983)) ##### *Blackd* - Introduce winloop to be used when windows in use which enables blackd to run faster on windows when winloop is installed. ([#4996](psf/black#4996)) ##### Integrations - Remove unused gallery script ([#5030](psf/black#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](psf/black#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](psf/black#4987)) - Add detailed documentation for formatting Jupyter Notebooks ([#5009](psf/black#5009)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/luke/instant-msg-api/pulls/246 Reviewed-by: Luke Tainton <luke@tainton.uk> Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [black](https://github.com/psf/black) ([changelog](https://github.com/psf/black/blob/main/CHANGES.md)) | `<26.1.1,>=26.1.0` → `<26.3.1,>=26.3.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/black/26.3.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/black/26.1.0/26.3.0?slim=true) | --- ### Release Notes <details> <summary>psf/black (black)</summary> ### [`v26.3.0`](https://github.com/psf/black/blob/HEAD/CHANGES.md#2630) [Compare Source](psf/black@26.1.0...26.3.0) ##### Stable style - Don't double-decode input, causing non-UTF-8 files to be corrupted ([#4964](psf/black#4964)) - Fix crash on standalone comment in lambda default arguments ([#4993](psf/black#4993)) - Preserve parentheses when `# type: ignore` comments would be merged with other comments on the same line, preventing AST equivalence failures ([#4888](psf/black#4888)) ##### Preview style - Fix bug where `if` guards in `case` blocks were incorrectly split when the pattern had a trailing comma ([#4884](psf/black#4884)) - Fix `string_processing` crashing on unassigned long string literals with trailing commas (one-item tuples) ([#4929](psf/black#4929)) - Simplify implementation of the power operator "hugging" logic ([#4918](psf/black#4918)) ##### Packaging - Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments ([#4930](psf/black#4930)) ##### Performance - Introduce winloop for windows as an alternative to uvloop ([#4996](psf/black#4996)) - Remove deprecated function `uvloop.install()` in favor of `uvloop.new_event_loop()` ([#4996](psf/black#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](psf/black#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](psf/black#4983)) ##### *Blackd* - Introduce winloop to be used when windows in use which enables blackd to run faster on windows when winloop is installed. ([#4996](psf/black#4996)) ##### Integrations - Remove unused gallery script ([#5030](psf/black#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](psf/black#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](psf/black#4987)) - Add detailed documentation for formatting Jupyter Notebooks ([#5009](psf/black#5009)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/epage/pulls/208 Reviewed-by: Luke Tainton <luke@tainton.uk> Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [black](https://github.com/psf/black) ([changelog](https://github.com/psf/black/blob/main/CHANGES.md)) | `<26.1.1,>=26.1.0` → `<26.3.1,>=26.3.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/black/26.3.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/black/26.1.0/26.3.0?slim=true) | --- ### Release Notes <details> <summary>psf/black (black)</summary> ### [`v26.3.0`](https://github.com/psf/black/blob/HEAD/CHANGES.md#2630) [Compare Source](psf/black@26.1.0...26.3.0) ##### Stable style - Don't double-decode input, causing non-UTF-8 files to be corrupted ([#4964](psf/black#4964)) - Fix crash on standalone comment in lambda default arguments ([#4993](psf/black#4993)) - Preserve parentheses when `# type: ignore` comments would be merged with other comments on the same line, preventing AST equivalence failures ([#4888](psf/black#4888)) ##### Preview style - Fix bug where `if` guards in `case` blocks were incorrectly split when the pattern had a trailing comma ([#4884](psf/black#4884)) - Fix `string_processing` crashing on unassigned long string literals with trailing commas (one-item tuples) ([#4929](psf/black#4929)) - Simplify implementation of the power operator "hugging" logic ([#4918](psf/black#4918)) ##### Packaging - Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments ([#4930](psf/black#4930)) ##### Performance - Introduce winloop for windows as an alternative to uvloop ([#4996](psf/black#4996)) - Remove deprecated function `uvloop.install()` in favor of `uvloop.new_event_loop()` ([#4996](psf/black#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](psf/black#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](psf/black#4983)) ##### *Blackd* - Introduce winloop to be used when windows in use which enables blackd to run faster on windows when winloop is installed. ([#4996](psf/black#4996)) ##### Integrations - Remove unused gallery script ([#5030](psf/black#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](psf/black#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](psf/black#4987)) - Add detailed documentation for formatting Jupyter Notebooks ([#5009](psf/black#5009)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/PwnedPW/pulls/326 Reviewed-by: Luke Tainton <luke@tainton.uk> Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [black](https://github.com/psf/black) ([changelog](https://github.com/psf/black/blob/main/CHANGES.md)) | `<26.1.1,>=26.1.0` → `<26.3.1,>=26.3.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/black/26.3.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/black/26.1.0/26.3.0?slim=true) | --- ### Release Notes <details> <summary>psf/black (black)</summary> ### [`v26.3.0`](https://github.com/psf/black/blob/HEAD/CHANGES.md#2630) [Compare Source](psf/black@26.1.0...26.3.0) ##### Stable style - Don't double-decode input, causing non-UTF-8 files to be corrupted ([#4964](psf/black#4964)) - Fix crash on standalone comment in lambda default arguments ([#4993](psf/black#4993)) - Preserve parentheses when `# type: ignore` comments would be merged with other comments on the same line, preventing AST equivalence failures ([#4888](psf/black#4888)) ##### Preview style - Fix bug where `if` guards in `case` blocks were incorrectly split when the pattern had a trailing comma ([#4884](psf/black#4884)) - Fix `string_processing` crashing on unassigned long string literals with trailing commas (one-item tuples) ([#4929](psf/black#4929)) - Simplify implementation of the power operator "hugging" logic ([#4918](psf/black#4918)) ##### Packaging - Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments ([#4930](psf/black#4930)) ##### Performance - Introduce winloop for windows as an alternative to uvloop ([#4996](psf/black#4996)) - Remove deprecated function `uvloop.install()` in favor of `uvloop.new_event_loop()` ([#4996](psf/black#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](psf/black#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](psf/black#4983)) ##### *Blackd* - Introduce winloop to be used when windows in use which enables blackd to run faster on windows when winloop is installed. ([#4996](psf/black#4996)) ##### Integrations - Remove unused gallery script ([#5030](psf/black#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](psf/black#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](psf/black#4987)) - Add detailed documentation for formatting Jupyter Notebooks ([#5009](psf/black#5009)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/roboluke/pulls/431 Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

Ankitsinghsisodya and others added 2 commits December 30, 2025 07:14

[pre-commit.ci] auto fixes from pre-commit.com hooks

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for more information, see https://pre-commit.ci

cobaltt7 mentioned this pull request Jan 1, 2026

Fix string_processing crash for one-item tuple string literals #4917

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Merge branch 'main' into fix/string-processing-trailing-comma-4912

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Ankitsinghsisodya and others added 2 commits January 21, 2026 01:15

Merge branch 'main' into fix/string-processing-trailing-comma-4912

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Merge branch 'main' into fix/string-processing-trailing-comma-4912

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cobaltt7 merged commit 14713ac into psf:main Jan 23, 2026
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Fix `string_processing` error with unassigned long string literal with trailing comma#4929

Fix `string_processing` error with unassigned long string literal with trailing comma#4929
cobaltt7 merged 5 commits intopsf:mainfrom
Ankitsinghsisodya:fix/string-processing-trailing-comma-4912

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Ankitsinghsisodya commented Dec 30, 2025 •

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