Bump black from 25.12.0 to 26.3.1

[dependabot]

Bumps black from 25.12.0 to 26.3.1.

Release notes

Sourced from black's releases.

26.3.1

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)

26.3.0

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

... (truncated)

Changelog

Sourced from black's changelog.

26.3.1

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)

26.3.0

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)

... (truncated)

Commits

• c6755bb Prepare release 26.3.1 (#5046)
• 69973fd Harden blackd browser-facing request handling (#5039)
• 4937fe6 Fix some shenanigans with the cache file and IPython (#5038)
• 2e641d1 docs: remove outdated Black Playground references (#5044)
• c014b22 Remove unused internal code (#5041)
• 0dae20b Add new changelog (#5036)
• c5c1cbd Minor release patches (#5035)
• 7e5a828 docs: clarify relationship between Black style and PEP 8 (#5025)
• 69705de docs: add clearer pyproject configuration guidance (#5026)
• 35ea679 Prepare release 26.3.0 (#5032)
• Additional commits viewable in compare view

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Note

Low Risk
Only updates the pinned black dev dependency, which may cause minor formatting diffs but does not change runtime code.

Overview
Bumps the pinned Python formatter black version in dev_requirements.txt from 25.12.0 to 26.3.1.

^{Written by Cursor Bugbot for commit dea1423. This will update automatically on new commits. Configure here.}

[koletzilla]

Checked it. This is related to the CVE-2026-32274:

Black is the uncompromising Python code formatter. Prior to 26.3.1, Black writes a cache file, the name of which is computed from various formatting options. The value of the --python-cell-magics option was placed in the filename without sanitization, which allowed an attacker who controls the value of this argument to write cache files to arbitrary file system locations. Fixed in Black 26.3.1.

Two conclusions:

• A community PR may try to do something, but as the GA executions from external contributions require explicit permissions, so it's unlikely this will happen without being seen first.
• Currently dbt-core is incompatible with the Black version that fixes it because of internal incompatibility with a transitive dependence: pathspec. That's the reason the CI is failing in this PR. Reported in dbt-core here: [Feature] requirements compatibility with mypy 1.20.x (upcoming) dbt-labs/dbt-core#12385 (comment)