<!--
Thank you for contributing to Ruff! To help us out with reviewing, please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title?
- Does this pull request include references to any relevant issues?
-->
## Summary
This PR uses rayon to parallelize the stability check by scheduling each project as its own task.
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
I ran the ecosystem check. It now makes use of all cores (except at the end, there are some large projects).
## Performance
The check now completes in minutes where it took about 30 minutes before.
<!-- How was it tested? -->
<!--
Thank you for contributing to Ruff! To help us out with reviewing, please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title?
- Does this pull request include references to any relevant issues?
-->
## Summary
This PR adds a new `PyFormatOptions` struct that stores the python formatter options.
The new options aren't used yet, with the exception of magical trailing commas and the options passed to the printer.
I'll follow up with more PRs that use the new options (e.g. `QuoteStyle`).
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
`cargo test` I'll follow up with a new PR that adds support for overriding the options in our fixture tests.
## Summary
This contains three changes:
* repos in `check_ecosystem.py` are stored as `org:name` instead of
`org/name` to create a flat directory layout
* `check_ecosystem.py` performs a maximum of 50 parallel jobs at the
same time to avoid consuming to much RAM
* `check-formatter-stability` gets a new option `--multi-project` so
it's possible to do `cargo run --bin ruff_dev --
check-formatter-stability --multi-project target/checkouts`
With these three changes it becomes easy to check the formatter
stability over a larger number of repositories. This is part of the
integration of integrating formatter regressions checks into the
ecosystem checks.
## Test Plan
```shell
python scripts/check_ecosystem.py --checkouts target/checkouts --projects github_search.jsonl -v $(which true) $(which true)
cargo run --bin ruff_dev -- check-formatter-stability --multi-project target/checkouts
```
## Summary
We want to ensure that once formatted content stays the same when
formatted again, which is known as formatter stability or formatter
idempotency, and that the formatter prints syntactically valid code. As
our test cases cover only a limited amount of code, this allows checking
entire repositories.
This adds a new subcommand to `ruff_dev` which can be invoked as `cargo
run --bin ruff_dev -- check-formatter-stability <repo>`. While initially
only intended to check stability, it has also found cases where the
formatter printed invalid syntax or panicked.
## Test Plan
Running this on cpython is already identifying bugs
(https://github.com/astral-sh/ruff/pull/5089)
