Summary
--
Updates `fuzz.py` to run with `--preview`, which should allow it to
catch semantic syntax errors.
Test Plan
--
@AlexWaygood and I temporarily made any named expression a semantic
syntax error and checked that this led to fuzzing errors. We also tested
that reverting the `--preview` addition did not show any errors.
We also ran the fuzzer on 500 seeds on `main` but didn't find any
issues, (un)fortunately.
The red-knot CLI changed since the fuzzer script was added; update it to
work with current red-knot CLI.
Also add some notes on how to ensure local changes to the fuzzer script
are picked up.
## Summary
This PR builds on the changes in #16220 to pass a target Python version
to the parser. It also adds the `Parser::unsupported_syntax_errors` field, which
collects version-related syntax errors while parsing. These syntax
errors are then turned into `Message`s in ruff (in preview mode).
This PR only detects one syntax error (`match` statement before Python
3.10), but it has been pretty quick to extend to several other simple
errors (see #16308 for example).
## Test Plan
The current tests are CLI tests in the linter crate, but these could be
supplemented with inline parser tests after #16357.
I also tested the display of these syntax errors in VS Code:
---------
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
## Summary
This PR gets rid of the `requirements.in` and `requirements.txt` files
in the `scripts/fuzz-parser` directory, and replaces them with
`pyproject.toml` and `uv.lock` files. The script is renamed from
`fuzz-parser` to `py-fuzzer` (since it can now also be used to fuzz
red-knot as well as the parser, following
https://github.com/astral-sh/ruff/pull/14566), and moved from the
`scripts/` directory to the `python/` directory, since it's now a
(uv)-pip-installable project in its own right.
I've been resisting this for a while, because conceptually this script
just doesn't feel "complicated" enough to me for it to be a full-blown
package. However, I think it's time to do this. Making it a proper
package has several advantages:
- It means we can run it from the project root using `uv run` without
having to activate a virtual environment and ensure that all required
dependencies are installed into that environment
- Using a `pyproject.toml` file means that we can express that the
project requires Python 3.12+ to run properly; this wasn't possible
before
- I've been running mypy on the project locally when I've been working
on it or reviewing other people's PRs; now I can put the mypy config for
the project in the `pyproject.toml` file
## Test Plan
I manually tested that all the commands detailed in
`python/py-fuzzer/README.md` work for me locally.
---------
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
