Summary
--
This is a very simple output format, the only decision is what to do if
the file
is missing from the diagnostic. For now, I opted to `unwrap_or_default`
both the
path and the `OneIndexed` row number, giving `:1: main diagnostic
message` in
the test without a file.
Another quirk here is that the path is relativized. I just pasted in the
`relativize_path` and `get_cwd` implementations from `ruff_linter::fs`
for now,
but maybe there's a better place for them.
I didn't see any details about why this needs to be relativized in the
original
[issue](https://github.com/astral-sh/ruff/issues/1953),
[PR](https://github.com/astral-sh/ruff/pull/1995), or in the pylint
[docs](https://flake8.pycqa.org/en/latest/internal/formatters.html#pylint-formatter),
but it did change the results of the CLI integration test when I tried
deleting
it. I haven't been able to reproduce that in the CLI, though, so it may
only
happen with `Command::current_dir`.
Test Plan
--
Tests ported from `ruff_linter` and a new test for the case with no file
---------
Co-authored-by: Micha Reiser <micha@reiser.io>