## Summary
This PR updates the lexer tests to use the snapshot testing framework.
It also
makes the following changes:
* Remove the use of macros in the lexer tests
* Use `test_case` for EOL tests
## Test Plan
```
cargo test --package ruff_python_parser --lib --all-features -- lexer::tests --no-capture
```
In https://github.com/astral-sh/ruff/pull/6616 we are adding support for
nested replacements in format specifiers which makes actually formatting
strings infeasible without a great deal of complexity. Since we're not
using these functions (they just exist for runtime use in RustPython),
we can just remove them.
## Summary
Fixes some TODOs introduced in
https://github.com/astral-sh/ruff/pull/6538. In short, given an
expression like `1 if x > 0 else "Hello, world!"`, we now return a union
type that says the expression can resolve to either an `int` or a `str`.
The system remains very limited, it only works for obvious primitive
types, and there's no attempt to do inference on any more complex
variables. (If any expression yields `Unknown` or `TypeError`, we
propagate that result throughout and abort on the client's end.)
**Summary** Some files seems notoriously slow in the formatter (secons in debug mode). This time was however almost exclusively spent in the diff algorithm to collect the similarity index, so i replaced that. I kept `similar` for printing actual diff to avoid rewriting that too, with the disadvantage that we now have to diff libraries in format_dev.
I used this PR to remove the spinner from tracing-indicatif and changed `flamegraph --perfdata perf.data` to `flamegraph --perfdata perf.data --no-inline` as the former wouldn't finish for me on release builds with debug info.
## Summary
This PR adds the implementation for the new Jupyter AST nodes i.e.,
`ExprLineMagic` and `StmtLineMagic`.
## Test Plan
Add test cases for `unparse` containing magic commands
resolves: #6087
Reimplements https://github.com/astral-sh/ruff/pull/3104
Closes https://github.com/astral-sh/ruff/issues/5726
Note that we will generate the hash for a cache key twice in normal
operation. Once to check for the cached item and again to update the
cache. We could optimize this by generating the hash once in
`diagnostics::lint_file` and passing the `u64` into `get` and `update`.
We'd probably want to wrap it in a `CacheKeyHash` enum for type safety.
## Test plan
Unit tests for Windows and Unix.
Manual test with case from issue
```
❯ touch fake.py
❯ chmod +x fake.py
❯ ./target/debug/ruff --select EXE fake.py
fake.py:1:1: EXE002 The file is executable but no shebang is present
Found 1 error.
❯ chmod -x fake.py
❯ ./target/debug/ruff --select EXE fake.py
```
I don't know whether we want to make this change but here's some data...
Binary size:
- `main`: 30,384
- `charlie/match-phf`: 30,416
llvm-lines:
- `main`: 1,784,148
- `charlie/match-phf`: 1,789,877
llvm-lines and binary size are both unchanged (or, by < 5) when moving
from `u8` to `u32` return types, and even when moving to `char` keys and
values. I didn't expect this, but I'm not very knowledgable on this
topic.
Performance:
```
Confusables/match/src time: [4.9102 µs 4.9352 µs 4.9777 µs]
change: [+1.7469% +2.2421% +2.8710%] (p = 0.00 < 0.05)
Performance has regressed.
Found 12 outliers among 100 measurements (12.00%)
2 (2.00%) low mild
4 (4.00%) high mild
6 (6.00%) high severe
Confusables/match-with-skip/src
time: [2.0676 µs 2.0945 µs 2.1317 µs]
change: [+0.9384% +1.6000% +2.3920%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 8 outliers among 100 measurements (8.00%)
3 (3.00%) high mild
5 (5.00%) high severe
Confusables/phf/src time: [31.087 µs 31.188 µs 31.305 µs]
change: [+1.9262% +2.2188% +2.5496%] (p = 0.00 < 0.05)
Performance has regressed.
Found 15 outliers among 100 measurements (15.00%)
3 (3.00%) low mild
6 (6.00%) high mild
6 (6.00%) high severe
Confusables/phf-with-skip/src
time: [2.0470 µs 2.0486 µs 2.0502 µs]
change: [-0.3093% -0.1446% +0.0106%] (p = 0.08 > 0.05)
No change in performance detected.
Found 4 outliers among 100 measurements (4.00%)
2 (2.00%) high mild
2 (2.00%) high severe
```
The `-with-skip` variants add our optimization which first checks
whether the character is ASCII. So `match` is way, way faster than PHF,
but it tends not to matter since almost all source code is ASCII anyway.
**Summary** I accidentally merged earlier while the RustPython parser
rev was still pointing to the feature branch instead of to the merged
main. This make the rev point to the RustPython parser repo main again
**Summary** Fix implemented in
https://github.com/astral-sh/RustPython-Parser/pull/35: Previously,
empty lambda arguments (e.g. `lambda: 1`) would get the range of the
entire expression, which leads to incorrect comment placement. Now empty
lambda arguments get an empty range between the `lambda` and the `:`
tokens.
**Test Plan** Added a regression test.
149 instances of unstable formatting remaining.
```
$ cargo run --bin ruff_dev --release -- format-dev --stability-check --error-file formatter-ecosystem-errors.txt --multi-project target/checkouts > formatter-ecosystem-progress.txt
$ rg "Unstable formatting" target/formatter-ecosystem-errors.txt | wc -l
149
```
## Summary
It can happen that we can't read a file (a python file, a jupyter
notebook or pyproject.toml), which needs to be handled and handled
consistently for all file types. Instead of using `Err` or `error!`, we
emit E602 with the io error as message and continue. This PR makes sure
we handle all three cases consistently, emit E602.
I'm not convinced that it should be possible to disable io errors, but
we now handle the regular case consistently and at least print warning
consistently.
I went with `warn!` but i can change them all to `error!`, too.
It also checks the error case when a pyproject.toml is not readable. The
error message is not very helpful, but it's now a bit clearer that
actually ruff itself failed instead vs this being a diagnostic.
## Examples
This is how an Err of `run` looks now:
With an unreadable file and `IOError` disabled:
(we lint zero files but count files before linting not during so we exit
0)
I'm not sure if it should (or if we should take a different path with
manual ExitStatus), but this currently also triggers when `files` is
empty:
## Test Plan
Unix only: Create a temporary directory with files with permissions
`000` (not readable by the owner) and run on that directory. Since this
breaks the assumptions of most of the test code (single file, `ruff`
instead of `ruff_cli`), the test code is rather cumbersome and looks a
bit misplaced; i'm happy about suggestions to fit it in closer with the
other tests or streamline it in other ways. I added another test for
when the entire directory is not readable.
## Summary
This crate now contains utilities for dealing with trivia more broadly:
whitespace, newlines, "simple" trivia lexing, etc. So renaming it to
reflect its increased responsibilities.
To avoid conflicts, I've also renamed `Token` and `TokenKind` to
`SimpleToken` and `SimpleTokenKind`.
## Summary
The motivation here is that it will make this rule easier to rewrite as
a deferred check. Right now, we can't run this rule in the deferred
phase, because it depends on the `except_handler` to power its autofix.
Instead of lexing the `except_handler`, we can use the `SimpleTokenizer`
from the formatter, and just lex forwards and backwards.
For context, this rule detects the unused `e` in:
```python
try:
pass
except ValueError as e:
pass
```
## Summary
Previously, `StmtIf` was defined recursively as
```rust
pub struct StmtIf {
pub range: TextRange,
pub test: Box<Expr>,
pub body: Vec<Stmt>,
pub orelse: Vec<Stmt>,
}
```
Every `elif` was represented as an `orelse` with a single `StmtIf`. This
means that this representation couldn't differentiate between
```python
if cond1:
x = 1
else:
if cond2:
x = 2
```
and
```python
if cond1:
x = 1
elif cond2:
x = 2
```
It also makes many checks harder than they need to be because we have to
recurse just to iterate over an entire if-elif-else and because we're
lacking nodes and ranges on the `elif` and `else` branches.
We change the representation to a flat
```rust
pub struct StmtIf {
pub range: TextRange,
pub test: Box<Expr>,
pub body: Vec<Stmt>,
pub elif_else_clauses: Vec<ElifElseClause>,
}
pub struct ElifElseClause {
pub range: TextRange,
pub test: Option<Expr>,
pub body: Vec<Stmt>,
}
```
where `test: Some(_)` represents an `elif` and `test: None` an else.
This representation is different tradeoff, e.g. we need to allocate the
`Vec<ElifElseClause>`, the `elif`s are now different than the `if`s
(which matters in rules where want to check both `if`s and `elif`s) and
the type system doesn't guarantee that the `test: None` else is actually
last. We're also now a bit more inconsistent since all other `else`,
those from `for`, `while` and `try`, still don't have nodes. With the
new representation some things became easier, e.g. finding the `elif`
token (we can use the start of the `ElifElseClause`) and formatting
comments for if-elif-else (no more dangling comments splitting, we only
have to insert the dangling comment after the colon manually and set
`leading_alternate_branch_comments`, everything else is taken of by
having nodes for each branch and the usual placement.rs fixups).
## Merge Plan
This PR requires coordination between the parser repo and the main ruff
repo. I've split the ruff part, into two stacked PRs which have to be
merged together (only the second one fixes all tests), the first for the
formatter to be reviewed by @michareiser and the second for the linter
to be reviewed by @charliermarsh.
* MH: Review and merge
https://github.com/astral-sh/RustPython-Parser/pull/20
* MH: Review and merge or move later in stack
https://github.com/astral-sh/RustPython-Parser/pull/21
* MH: Review and approve
https://github.com/astral-sh/RustPython-Parser/pull/22
* MH: Review and approve formatter PR
https://github.com/astral-sh/ruff/pull/5459
* CM: Review and approve linter PR
https://github.com/astral-sh/ruff/pull/5460
* Merge linter PR in formatter PR, fix ecosystem checks (ecosystem
checks can't run on the formatter PR and won't run on the linter PR, so
we need to merge them first)
* Merge https://github.com/astral-sh/RustPython-Parser/pull/22
* Create tag in the parser, update linter+formatter PR
* Merge linter+formatter PR https://github.com/astral-sh/ruff/pull/5459
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
For formatter instabilities, the message we get look something like
this:
```text
Unstable formatting /home/konsti/ruff/target/checkouts/deepmodeling:dpdispatcher/dpdispatcher/slurm.py
@@ -47,9 +47,9 @@
- script_header_dict["slurm_partition_line"] = (
- NOT_YET_IMPLEMENTED_ExprJoinedStr
- )
+ script_header_dict[
+ "slurm_partition_line"
+ ] = NOT_YET_IMPLEMENTED_ExprJoinedStr
Unstable formatting /home/konsti/ruff/target/checkouts/deepmodeling:dpdispatcher/dpdispatcher/pbs.py
@@ -26,9 +26,9 @@
- pbs_script_header_dict["select_node_line"] += (
- NOT_YET_IMPLEMENTED_ExprJoinedStr
- )
+ pbs_script_header_dict[
+ "select_node_line"
+ ] += NOT_YET_IMPLEMENTED_ExprJoinedStr
```
For ruff crashes. you don't even get that but just the file that crashed
it. To extract the actual bug, you'd need to manually remove parts of
the file, rerun to see if the bug still occurs (and revert if it
doesn't) until you have a minimal example.
With this script, you run
```shell
cargo run --bin ruff_shrinking -- target/checkouts/deepmodeling:dpdispatcher/dpdispatcher/slurm.py target/minirepo/code.py "Unstable formatting" "target/debug/ruff_dev format-dev --stability-check target/minirepo"
```
and get
```python
class Slurm():
def gen_script_header(self, job):
if resources.queue_name != "":
script_header_dict["slurm_partition_line"] = f"#SBATCH --partition {resources.queue_name}"
```
which is an nice minimal example.
I've been using this script and it would be easier for me if this were
part of main. The main disadvantage to merging is that it adds
additional dependencies.
## Test Plan
I've been using this for a number of minimization. This is an internal
helper script you only run manually. I could add a test that minimizes a
rule violation if required.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
Comparing repos with black requires that we use the settings as black,
notably line length and magic trailing comma behaviour. Excludes and
preserving quotes (vs. a preference for either quote style) is not yet
implemented because they weren't needed for the test projects.
In the other two commits i fixed the output when the progress bar is
hidden (this way is recommonded in the indicatif docs), added a
`scratch.pyi` file to gitignore because black formats stub files
differently and also updated the ecosystem readme with the projects json
without forks.
## Test Plan
I added a `line-length` vs `line_length` test. Otherwise only my
personal usage atm, a PR to integrate the script into the CI to check
some projects will follow.
## Summary
Do not raise `EXE001` and `EXE002` if WSL is detected. Uses the
[`wsl`](https://crates.io/crates/wsl) crate.
Closes#5445.
## Test Plan
`cargo test`
I don't use Windows, so was unable to test on a WSL environment. It
would be good if someone who runs Windows could check the functionality.
## Summary
It turns out that just doing this match directly without `AhoCorasick`
is much faster, like 2x (and removes one dependency, though we likely
already rely on this transitively).
## Summary
Historically, we only used a fork to enable building without pyo3. But
pyo3 is an optional feature. I may've just not understood how to
accomplish this way back when.
## Summary
This extends the `ruff_dev` formatter script util. Instead of only doing
stability checks, you can now choose different compatible options on the
CLI and get statistics.
* It adds an option the formats all files that ruff would check to allow
looking at an entire black-formatted repository with `git diff`
* It computes the [Jaccard
index](https://en.wikipedia.org/wiki/Jaccard_index) as a measure of
deviation between input and output, which is useful as single number
metric for assessing our current deviations from black.
* It adds progress bars to both the single projects as well as the
multi-project mode.
* It adds an option to write the multi-project output to a file
Sample usage:
```
$ cargo run --bin ruff_dev -- format-dev --stability-check crates/ruff/resources/test/cpython
$ cargo run --bin ruff_dev -- format-dev --stability-check /home/konsti/projects/django
Syntax error in /home/konsti/projects/django/tests/test_runner_apps/tagged/tests_syntax_error.py: source contains syntax errors (parser error): BaseError { error: UnrecognizedToken(Name { name: "syntax_error" }, None), offset: 131, source_path: "<filename>" }
Found 0 stability errors in 2755 files (jaccard index 0.911) in 9.75s
$ cargo run --bin ruff_dev -- format-dev --write /home/konsti/projects/django
```
Options:
```
Several utils related to the formatter which can be run on one or more repositories. The selected set of files in a repository is the same as for `ruff check`.
* Check formatter stability: Format a repository twice and ensure that it looks that the first and second formatting look the same. * Format: Format the files in a repository to be able to check them with `git diff` * Statistics: The subcommand the Jaccard index between the (assumed to be black formatted) input and the ruff formatted output
Usage: ruff_dev format-dev [OPTIONS] [FILES]...
Arguments:
[FILES]...
Like `ruff check`'s files. See `--multi-project` if you want to format an ecosystem checkout
Options:
--stability-check
Check stability
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.
--write
Format the files. Without this flag, the python files are not modified
--format <FORMAT>
Control the verbosity of the output
[default: default]
Possible values:
- minimal: Filenames only
- default: Filenames and reduced diff
- full: Full diff and invalid code
-x, --exit-first-error
Print only the first error and exit, `-x` is same as pytest
--multi-project
Checks each project inside a directory, useful e.g. if you want to check all of the ecosystem checkouts
--error-file <ERROR_FILE>
Write all errors to this file in addition to stdout. Only used in multi-project mode
```
## Test Plan
I ran this on django (2755 files, jaccard index 0.911) and discovered a
magic trailing comma problem and that we really needed to implement
import formatting. I ran the script on cpython to identify
https://github.com/astral-sh/ruff/pull/5558.
## Summary
I'll write up a more detailed description tomorrow, but in short, this
PR removes our regex-based implementation in favor of "manual" parsing.
I tried a couple different implementations. In the benchmarks below:
- `Directive/Regex` is our implementation on `main`.
- `Directive/Find` just uses `text.find("noqa")`, which is insufficient,
since it doesn't cover case-insensitive variants like `NOQA`, and
doesn't handle multiple `noqa` matches in a single like, like ` # Here's
a noqa comment # noqa: F401`. But it's kind of a baseline.
- `Directive/Memchr` uses three `memchr` iterative finders (one for
`noqa`, `NOQA`, and `NoQA`).
- `Directive/AhoCorasick` is roughly the variant checked-in here.
The raw results:
```
Directive/Regex/# noqa: F401
time: [273.69 ns 274.71 ns 276.03 ns]
change: [+1.4467% +1.8979% +2.4243%] (p = 0.00 < 0.05)
Performance has regressed.
Found 15 outliers among 100 measurements (15.00%)
3 (3.00%) low mild
8 (8.00%) high mild
4 (4.00%) high severe
Directive/Find/# noqa: F401
time: [66.972 ns 67.048 ns 67.132 ns]
change: [+2.8292% +2.9377% +3.0540%] (p = 0.00 < 0.05)
Performance has regressed.
Found 15 outliers among 100 measurements (15.00%)
1 (1.00%) low severe
3 (3.00%) low mild
8 (8.00%) high mild
3 (3.00%) high severe
Directive/AhoCorasick/# noqa: F401
time: [76.922 ns 77.189 ns 77.536 ns]
change: [+0.4265% +0.6862% +0.9871%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 8 outliers among 100 measurements (8.00%)
1 (1.00%) low mild
3 (3.00%) high mild
4 (4.00%) high severe
Directive/Memchr/# noqa: F401
time: [62.627 ns 62.654 ns 62.679 ns]
change: [-0.1780% -0.0887% -0.0120%] (p = 0.03 < 0.05)
Change within noise threshold.
Found 11 outliers among 100 measurements (11.00%)
1 (1.00%) low severe
5 (5.00%) low mild
3 (3.00%) high mild
2 (2.00%) high severe
Directive/Regex/# noqa: F401, F841
time: [321.83 ns 322.39 ns 322.93 ns]
change: [+8602.4% +8623.5% +8644.5%] (p = 0.00 < 0.05)
Performance has regressed.
Found 5 outliers among 100 measurements (5.00%)
1 (1.00%) low severe
2 (2.00%) low mild
1 (1.00%) high mild
1 (1.00%) high severe
Directive/Find/# noqa: F401, F841
time: [78.618 ns 78.758 ns 78.896 ns]
change: [+1.6909% +1.8771% +2.0628%] (p = 0.00 < 0.05)
Performance has regressed.
Found 3 outliers among 100 measurements (3.00%)
3 (3.00%) high mild
Directive/AhoCorasick/# noqa: F401, F841
time: [87.739 ns 88.057 ns 88.468 ns]
change: [+0.1843% +0.4685% +0.7854%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 11 outliers among 100 measurements (11.00%)
5 (5.00%) low mild
3 (3.00%) high mild
3 (3.00%) high severe
Directive/Memchr/# noqa: F401, F841
time: [80.674 ns 80.774 ns 80.860 ns]
change: [-0.7343% -0.5633% -0.4031%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 14 outliers among 100 measurements (14.00%)
4 (4.00%) low severe
9 (9.00%) low mild
1 (1.00%) high mild
Directive/Regex/# noqa time: [194.86 ns 195.93 ns 196.97 ns]
change: [+11973% +12039% +12103%] (p = 0.00 < 0.05)
Performance has regressed.
Found 6 outliers among 100 measurements (6.00%)
5 (5.00%) low mild
1 (1.00%) high mild
Directive/Find/# noqa time: [25.327 ns 25.354 ns 25.383 ns]
change: [+3.8524% +4.0267% +4.1845%] (p = 0.00 < 0.05)
Performance has regressed.
Found 9 outliers among 100 measurements (9.00%)
6 (6.00%) high mild
3 (3.00%) high severe
Directive/AhoCorasick/# noqa
time: [34.267 ns 34.368 ns 34.481 ns]
change: [+0.5646% +0.8505% +1.1281%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 5 outliers among 100 measurements (5.00%)
5 (5.00%) high mild
Directive/Memchr/# noqa time: [21.770 ns 21.818 ns 21.874 ns]
change: [-0.0990% +0.1464% +0.4046%] (p = 0.26 > 0.05)
No change in performance detected.
Found 10 outliers among 100 measurements (10.00%)
4 (4.00%) low mild
4 (4.00%) high mild
2 (2.00%) high severe
Directive/Regex/# type: ignore # noqa: E501
time: [278.76 ns 279.69 ns 280.72 ns]
change: [+7449.4% +7469.8% +7490.5%] (p = 0.00 < 0.05)
Performance has regressed.
Found 3 outliers among 100 measurements (3.00%)
1 (1.00%) low mild
1 (1.00%) high mild
1 (1.00%) high severe
Directive/Find/# type: ignore # noqa: E501
time: [67.791 ns 67.976 ns 68.184 ns]
change: [+2.8321% +3.1735% +3.5418%] (p = 0.00 < 0.05)
Performance has regressed.
Found 6 outliers among 100 measurements (6.00%)
5 (5.00%) high mild
1 (1.00%) high severe
Directive/AhoCorasick/# type: ignore # noqa: E501
time: [75.908 ns 76.055 ns 76.210 ns]
change: [+0.9269% +1.1427% +1.3955%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 1 outliers among 100 measurements (1.00%)
1 (1.00%) high severe
Directive/Memchr/# type: ignore # noqa: E501
time: [72.549 ns 72.723 ns 72.957 ns]
change: [+1.5881% +1.9660% +2.3974%] (p = 0.00 < 0.05)
Performance has regressed.
Found 15 outliers among 100 measurements (15.00%)
10 (10.00%) high mild
5 (5.00%) high severe
Directive/Regex/# type: ignore # nosec
time: [66.967 ns 67.075 ns 67.207 ns]
change: [+1713.0% +1715.8% +1718.9%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
1 (1.00%) low severe
3 (3.00%) low mild
2 (2.00%) high mild
4 (4.00%) high severe
Directive/Find/# type: ignore # nosec
time: [18.505 ns 18.548 ns 18.597 ns]
change: [+1.3520% +1.6976% +2.0333%] (p = 0.00 < 0.05)
Performance has regressed.
Found 4 outliers among 100 measurements (4.00%)
4 (4.00%) high mild
Directive/AhoCorasick/# type: ignore # nosec
time: [16.162 ns 16.206 ns 16.252 ns]
change: [+1.2919% +1.5587% +1.8430%] (p = 0.00 < 0.05)
Performance has regressed.
Found 4 outliers among 100 measurements (4.00%)
3 (3.00%) high mild
1 (1.00%) high severe
Directive/Memchr/# type: ignore # nosec
time: [39.192 ns 39.233 ns 39.276 ns]
change: [+0.5164% +0.7456% +0.9790%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 13 outliers among 100 measurements (13.00%)
2 (2.00%) low severe
4 (4.00%) low mild
3 (3.00%) high mild
4 (4.00%) high severe
Directive/Regex/# some very long comment that # is interspersed with characters but # no directive
time: [81.460 ns 81.578 ns 81.703 ns]
change: [+2093.3% +2098.8% +2104.2%] (p = 0.00 < 0.05)
Performance has regressed.
Found 4 outliers among 100 measurements (4.00%)
2 (2.00%) low mild
2 (2.00%) high mild
Directive/Find/# some very long comment that # is interspersed with characters but # no directive
time: [26.284 ns 26.331 ns 26.387 ns]
change: [+0.7554% +1.1027% +1.3832%] (p = 0.00 < 0.05)
Change within noise threshold.
Found 6 outliers among 100 measurements (6.00%)
5 (5.00%) high mild
1 (1.00%) high severe
Directive/AhoCorasick/# some very long comment that # is interspersed with characters but # no direc...
time: [28.643 ns 28.714 ns 28.787 ns]
change: [+1.3774% +1.6780% +2.0028%] (p = 0.00 < 0.05)
Performance has regressed.
Found 2 outliers among 100 measurements (2.00%)
2 (2.00%) high mild
Directive/Memchr/# some very long comment that # is interspersed with characters but # no directive
time: [55.766 ns 55.831 ns 55.897 ns]
change: [+1.5802% +1.7476% +1.9021%] (p = 0.00 < 0.05)
Performance has regressed.
Found 2 outliers among 100 measurements (2.00%)
2 (2.00%) low mild
```
While memchr is faster than aho-corasick in some of the common cases
(like `# noqa: F401`), the latter is way, way faster when there _isn't_
a match (like 2x faster -- see the last two cases). Since most comments
_aren't_ `noqa` comments, this felt like the right tradeoff. Note that
all implementations are significantly faster than the regex version.
(I know I originally reported a 10x speedup, but I ended up improving
the regex version a bit in some prior PRs, so it got unintentionally
faster via some refactors.)
There's also one behavior change in here, which is that we now allow
variable spaces, e.g., `#noqa` or `# noqa`. Previously, we required
exactly one space. This thus closes#5177.
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## 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.
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