Tasks: Ruff Integration for Python Linting & Formatting¶

Feature Overview¶

Replace flake8 (linter) and black (formatter) with ruff for Python file processing in linthis, providing 10-100x speed improvements.

All tasks have been implemented.

ID	Priority	Story	Status
US1	P1	As a developer, I want Python linting to use ruff instead of flake8 so that lint checks are faster	Done
US2	P1	As a developer, I want Python formatting to use ruff instead of black so that formatting is faster	Done
US3	P2	As a developer, I want ruff configuration generated by --init-configs so that I can customize rules	Done
US4	P3	As a developer, I want to benchmark ruff vs flake8+black so that I can see the speed improvement	Done

[x] T001 Verify ruff is installed and accessible via ruff --version
[x] T002 Review existing Python checker implementation in src/checkers/python.rs
[x] T003 Review existing Python formatter implementation in src/formatters/python.rs

[x] T004 [P] Add RuffIssue struct for JSON deserialization in src/checkers/python.rs
[x] T005 [P] Add RuffLocation struct for JSON deserialization in src/checkers/python.rs
[x] T006 [P] Add RuffFix and RuffEdit structs for JSON deserialization in src/checkers/python.rs

Goal: Replace flake8 with ruff check for Python linting

Test Criteria: cargo test passes, linthis correctly detects Python lint issues using ruff

[x] T007 [US1] Update name() method to return "ruff" in src/checkers/python.rs
[x] T008 [US1] Update is_available() to check for ruff binary in src/checkers/python.rs
[x] T009 [US1] Implement parse_ruff_json_output() method to parse ruff JSON output in src/checkers/python.rs
[x] T010 [US1] Implement severity mapping from ruff codes (E/F->Error, W/N/B/S/A->Warning, others->Info) in src/checkers/python.rs
[x] T011 [US1] Update check() method to run ruff check --output-format json in src/checkers/python.rs
[x] T012 [US1] Remove old parse_flake8_output() and parse_flake8_line() methods in src/checkers/python.rs
[x] T013 [US1] Update module docstring from "pylint/flake8" to "ruff" in src/checkers/python.rs
[x] T014 [US1] Manual test: run cargo run -- --check-only --lang python on Python files with issues

Goal: Replace black with ruff format for Python formatting

Test Criteria: cargo test passes, linthis correctly formats Python files using ruff

[x] T015 [US2] Update name() method to return "ruff" in src/formatters/python.rs
[x] T016 [US2] Update is_available() to check for ruff binary in src/formatters/python.rs
[x] T017 [US2] Update format() method to run ruff format in src/formatters/python.rs
[x] T018 [US2] Update check() method to run ruff format --check in src/formatters/python.rs
[x] T019 [US2] Remove hard-coded --line-length 120 argument (use ruff config instead) in src/formatters/python.rs
[x] T020 [US2] Update module docstring from "black" to "ruff" in src/formatters/python.rs
[x] T021 [US2] Manual test: run cargo run -- --format-only --lang python on unformatted Python files

Goal: Update default config and --init-configs for ruff

Test Criteria: linthis --init-configs generates valid ruff configuration

[x] T022 [US3] Add [python] section with ruff settings in defaults/config.toml
[x] T023 [US3] Update generate_tool_configs() to create ruff.toml instead of .flake8 in src/main.rs
[x] T024 [US3] Update generate_tool_configs() to update pyproject.toml [tool.ruff] section in src/main.rs
[x] T025 [US3] Remove .flake8 generation from generate_tool_configs() in src/main.rs
[x] T026 [US3] Manual test: run cargo run -- --init-configs and verify ruff.toml is created

Goal: Add --benchmark flag to compare ruff vs flake8+black performance

Test Criteria: linthis --benchmark --lang python outputs comparison table

[x] T027 [US4] Add --benchmark CLI flag in src/main.rs
[x] T028 [US4] Create src/benchmark.rs module for benchmark logic
[x] T029 [US4] Implement run_flake8_benchmark() to time flake8 execution in src/benchmark.rs
[x] T030 [US4] Implement run_black_benchmark() to time black execution in src/benchmark.rs
[x] T031 [US4] Implement run_ruff_check_benchmark() to time ruff check execution in src/benchmark.rs
[x] T032 [US4] Implement run_ruff_format_benchmark() to time ruff format execution in src/benchmark.rs
[x] T033 [US4] Implement format_benchmark_table() to output ASCII table comparison in src/benchmark.rs
[x] T034 [US4] Add benchmark module to src/lib.rs
[x] T035 [US4] Wire --benchmark flag to benchmark execution in src/main.rs
[x] T036 [US4] Manual test: run cargo run -- --benchmark --lang python on a Python project

[x] T037 Update README.md to document ruff as the Python linter/formatter
[x] T038 Add migration notes for users switching from flake8+black to ruff in README.md
[x] T039 Run cargo clippy and fix any warnings
[x] T040 Run cargo test to verify all tests pass
[x] T041 Final manual test: run full linthis workflow on a Python project