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https://github.com/jbranchaud/til
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jbranchaud
82 lines
2.5 KiB
Markdown
82 lines
2.5 KiB
Markdown
# Lint And Format Project With Ruff
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[Ruff](https://docs.astral.sh/ruff/) is "an extremely fast Python linter and
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code formatter, written in Rust." I recently added it to my [`py-vmt` CLI project](https://github.com/jbranchaud/py-vmt) and here are some of the commands
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I used right out of the box.
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First, I use `uv` and so I installed it like so:
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```bash
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❯ uv add --dev ruff
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```
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First, I checked for linting errors. There were a bunch. The output looked like
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this:
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```bash
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❯ uv run ruff check
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F841 Local variable `frozen_datetime` is assigned to but never used
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--> tests/src/py_vmt/test_cli.py:88:43
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86 | 2026, 3, 14, 15, 5, 11, 0, datetime.timezone.utc
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87 | )
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88 | with freeze_time(initial_datetime) as frozen_datetime:
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| ^^^^^^^^^^^^^^^
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89 | # cancel session without one started
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90 | cancel_result = runner.invoke(cli, ["cancel"])
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help: Remove assignment to unused variable `frozen_datetime`
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...
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Found 11 errors.
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[*] 2 fixable with the `--fix` option (7 hidden fixes can be enabled with the `--unsafe-fixes` option).
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```
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Some of them could be automatically fixed, so I dealt with those first using the
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`--fix` flag.
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```bash
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❯ uv run ruff check --fix
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```
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The remaining lint issues I had to deal with manually. Once I had addressed all
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of them I got this message:
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```bash
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❯ uv run ruff check
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All checks passed!
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```
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With the lint issues out of the way, the next stuff was to use `ruff` to apply
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consistent auto-formatting across the entire project. Because I hadn't been
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using any auto-formatter up to this point on this project, I can expect the diff
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to be significant.
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I can start with a dry run using the `--check` flag. This gives a summary of how
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much formatting churn there is going to be.
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```bash
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❯ uv run ruff format --check
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Would reformat: src/py_vmt/cli.py
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Would reformat: src/py_vmt/session.py
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Would reformat: src/py_vmt/time_helpers.py
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Would reformat: tests/src/py_vmt/test_cli.py
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Would reformat: tests/src/py_vmt/test_session.py
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Would reformat: tests/src/py_vmt/test_time_helpers.py
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6 files would be reformatted, 3 files already formatted
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```
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I'm using git and I have a clean working copy, so there is no real harm in just
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going for it either.
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```bash
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❯ uv run ruff format
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6 files reformatted, 3 files left unchanged
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```
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That makes all the formatting changes and I can use `git diff` to browse through
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them before eventually committing them.
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See `uv run ruff check --help` and `uv run ruff format --help` for more details.
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