[flake8-bugbear] Accept immutable slice default arguments (B008)#21823
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ntBre merged 1 commit intoastral-sh:mainfrom Dec 8, 2025
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[flake8-bugbear] Accept immutable slice default arguments (B008)#21823ntBre merged 1 commit intoastral-sh:mainfrom
flake8-bugbear] Accept immutable slice default arguments (B008)#21823ntBre merged 1 commit intoastral-sh:mainfrom
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flake8-bugbear] Accept immutable slice default arguments (B008)
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Thank you!
Just a note in case of future reference, I checked the other callers of is_immutable_return_type (via is_immutable_func), and this change will also affect function-call-in-dataclass-default-argument (RUF009) and mutable-contextvar-default (B039).
But I think it's straightforward enough that we don't need to test every rule.
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…return * dcreager/die-die-intersections: (29 commits) simpler bounds [`pylint`] Detect subclasses of builtin exceptions (`PLW0133`) (#21382) Fix stack overflow with recursive generic protocols (depth limit) (#21858) New diagnostics for unused range suppressions (#21783) [ty] Use default settings in completion tests [ty] Infer type variables within generic unions (#21862) [ty] Fix overload filtering to prefer more "precise" match (#21859) [ty] Stabilize auto-import [ty] Fix reveal-type E2E test (#21865) [ty] Use concise message for LSP clients not supporting related diagnostic information (#21850) Include more details in Tokens 'offset is inside token' panic message (#21860) apply range suppressions to filter diagnostics (#21623) [ty] followup: add-import action for `reveal_type` too (#21668) [ty] Enrich function argument auto-complete suggestions with annotated types [ty] Add autocomplete suggestions for function arguments [`flake8-bugbear`] Accept immutable slice default arguments (`B008`) (#21823) [`pydocstyle`] Suppress `D417` for parameters with `Unpack` annotations (#21816) [ty] Remove legacy `concise_message` fallback behavior (#21847) [ty] Make Python-version subdiagnostics less verbose (#21849) [ty] Supress inlay hints when assigning a trivial initializer call (#21848) ...
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…return * dcreager/die-die-intersections: (31 commits) clippy reword comment simpler bounds [`pylint`] Detect subclasses of builtin exceptions (`PLW0133`) (#21382) Fix stack overflow with recursive generic protocols (depth limit) (#21858) New diagnostics for unused range suppressions (#21783) [ty] Use default settings in completion tests [ty] Infer type variables within generic unions (#21862) [ty] Fix overload filtering to prefer more "precise" match (#21859) [ty] Stabilize auto-import [ty] Fix reveal-type E2E test (#21865) [ty] Use concise message for LSP clients not supporting related diagnostic information (#21850) Include more details in Tokens 'offset is inside token' panic message (#21860) apply range suppressions to filter diagnostics (#21623) [ty] followup: add-import action for `reveal_type` too (#21668) [ty] Enrich function argument auto-complete suggestions with annotated types [ty] Add autocomplete suggestions for function arguments [`flake8-bugbear`] Accept immutable slice default arguments (`B008`) (#21823) [`pydocstyle`] Suppress `D417` for parameters with `Unpack` annotations (#21816) [ty] Remove legacy `concise_message` fallback behavior (#21847) ...
dcreager
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Dec 9, 2025
…return * dcreager/die-die-intersections: (31 commits) clippy reword comment simpler bounds [`pylint`] Detect subclasses of builtin exceptions (`PLW0133`) (#21382) Fix stack overflow with recursive generic protocols (depth limit) (#21858) New diagnostics for unused range suppressions (#21783) [ty] Use default settings in completion tests [ty] Infer type variables within generic unions (#21862) [ty] Fix overload filtering to prefer more "precise" match (#21859) [ty] Stabilize auto-import [ty] Fix reveal-type E2E test (#21865) [ty] Use concise message for LSP clients not supporting related diagnostic information (#21850) Include more details in Tokens 'offset is inside token' panic message (#21860) apply range suppressions to filter diagnostics (#21623) [ty] followup: add-import action for `reveal_type` too (#21668) [ty] Enrich function argument auto-complete suggestions with annotated types [ty] Add autocomplete suggestions for function arguments [`flake8-bugbear`] Accept immutable slice default arguments (`B008`) (#21823) [`pydocstyle`] Suppress `D417` for parameters with `Unpack` annotations (#21816) [ty] Remove legacy `concise_message` fallback behavior (#21847) ...
dcreager
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Dec 10, 2025
* origin/main: (33 commits) [ty] Simplify union lower bounds and intersection upper bounds in constraint sets (#21871) [ty] Collapse `never` paths in constraint set BDDs (#21880) Fix leading comment formatting for lambdas with multiple parameters (#21879) [ty] Type inference for `@asynccontextmanager` (#21876) Fix comment placement in lambda parameters (#21868) [`pylint`] Detect subclasses of builtin exceptions (`PLW0133`) (#21382) Fix stack overflow with recursive generic protocols (depth limit) (#21858) New diagnostics for unused range suppressions (#21783) [ty] Use default settings in completion tests [ty] Infer type variables within generic unions (#21862) [ty] Fix overload filtering to prefer more "precise" match (#21859) [ty] Stabilize auto-import [ty] Fix reveal-type E2E test (#21865) [ty] Use concise message for LSP clients not supporting related diagnostic information (#21850) Include more details in Tokens 'offset is inside token' panic message (#21860) apply range suppressions to filter diagnostics (#21623) [ty] followup: add-import action for `reveal_type` too (#21668) [ty] Enrich function argument auto-complete suggestions with annotated types [ty] Add autocomplete suggestions for function arguments [`flake8-bugbear`] Accept immutable slice default arguments (`B008`) (#21823) ...
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Closes issue #21565
Summary
As pointed out in the issue, slices are currently flagged by B008 but this behavior is incorrect because slices are immutable.
Test Plan
Added a test case in the "B006_B008.py" fixture. Sorry for the diff in the snapshots, the only thing that changes in those flies is the line numbers, though.
You can also test this manually with this file: