## Summary
Implement [implicit readlines
(FURB129)](https://github.com/dosisod/refurb/blob/master/refurb/checks/iterable/implicit_readlines.py)
lint.
## Notes
I need a help/an opinion about suggested implementations.
This implementation differs from the original one from `refurb` in the
following way. This implementation checks syntactically the call of the
method with the name `readlines()` inside `for` {loop|generator
expression}. The implementation from refurb also
[checks](https://github.com/dosisod/refurb/blob/master/refurb/checks/iterable/implicit_readlines.py#L43)
that callee is a variable with a type `io.TextIOWrapper` or
`io.BufferedReader`.
- I do not see a simple way to implement the same logic.
- The best I can have is something like
```rust
checker.semantic().binding(checker.semantic().resolve_name(attr_expr.value.as_name_expr()?)?).statement(checker.semantic())
```
and analyze cases. But this will be not about types, but about guessing
the type by assignment (or with) expression.
- Also this logic has several false negatives, when the callee is not a
variable, but the result of function call (e.g. `open(...)`).
- On the other side, maybe it is good to lint this on other things,
where this suggestion is not safe, and push the developers to change
their interfaces to be less surprising, comparing with the standard
library.
- Anyway while the current implementation has false-positives (I
mentioned some of them in the test) I marked the fixes to be unsafe.
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## Summary
Fixes#8151
This PR implements a new rule, `RUF027`.
## What it does
Checks for strings that contain f-string syntax but are not f-strings.
### Why is this bad?
An f-string missing an `f` at the beginning won't format anything, and
instead treat the interpolation syntax as literal.
### Example
```python
name = "Sarah"
dayofweek = "Tuesday"
msg = "Hello {name}! It is {dayofweek} today!"
```
It should instead be:
```python
name = "Sarah"
dayofweek = "Tuesday"
msg = f"Hello {name}! It is {dayofweek} today!"
```
## Heuristics
Since there are many possible string literals which contain syntax
similar to f-strings yet are not intended to be,
this lint will disqualify any literal that satisfies any of the
following conditions:
1. The string literal is a standalone expression. For example, a
docstring.
2. The literal is part of a function call with keyword arguments that
match at least one variable (for example: `format("Message: {value}",
value = "Hello World")`)
3. The literal (or a parent expression of the literal) has a direct
method call on it (for example: `"{value}".format(...)`)
4. The string has no `{...}` expression sections, or uses invalid
f-string syntax.
5. The string references variables that are not in scope, or it doesn't
capture variables at all.
6. Any format specifiers in the potential f-string are invalid.
## Test Plan
I created a new test file, `RUF027.py`, which is both an example of what
the lint should catch and a way to test edge cases that may trigger
false positives.
## Summary
This rule was added to `flake8-type-checking` as `TC010`. We're about to
stabilize it, so we might as well use the correct code.
See: https://github.com/astral-sh/ruff/issues/9573.
Fixes#7350
## Summary
* `--show-source` and `--no-show-source` are now deprecated.
* `output-format` supports two new variants, `full` and `concise`.
`text` is now a deprecated variant, and any use of it is treated as the
default serialization format.
* `--output-format` now default to `concise`
* In preview mode, `--output-format` defaults to `full`
* `--show-source` will still set `--output-format` to `full` if the
output format is not otherwise specified.
* likewise, `--no-show-source` can override an output format that was
set in a file-based configuration, though it will also be overridden by
`--output-format`
## Test Plan
A lot of tests were updated to use `--output-format=full`. Additional
tests were added to ensure the correct deprecation warnings appeared,
and that deprecated options behaved as intended.
# Conflicts:
# crates/ruff/tests/integration_test.rs
## Summary
This rule was added to flake8-bugbear. In general, we tend to prefer
redirecting to prominent plugins when our own rules are reimplemented
(since more projects have `B` activated than `RUF`).
## Test Plan
`cargo test`
# Conflicts:
# crates/ruff_linter/src/rules/ruff/rules/mod.rs
## Summary
Add a rule for defaultdict(default_factory=callable). Instead suggest
using defaultdict(callable).
See: https://github.com/astral-sh/ruff/issues/9509
If a user tries to bind a "non-callable" to default_factory, the rule
ignores it. Another option would be to warn that it's probably not what
you want. Because Python allows the following:
```python
from collections import defaultdict
defaultdict(default_factory=1)
```
this raises after you actually try to use it:
```python
dd = defaultdict(default_factory=1)
dd[1]
```
=>
```bash
KeyError: 1
```
Instead using callable directly in the constructor it will raise (not
being a callable):
```python
from collections import defaultdict
defaultdict(1)
```
=>
```bash
TypeError: first argument must be callable or None
```
## Test Plan
```bash
cargo test
```
## Summary
If you paste in the TOML for our default configuration (from the docs),
it's rejected by our JSON Schema:

It seems like the issue is with:
```toml
# Set the line length limit used when formatting code snippets in
# docstrings.
#
# This only has an effect when the `docstring-code-format` setting is
# enabled.
docstring-code-line-length = "dynamic"
```
Specifically, since that value uses a custom Serde implementation, I
guess Schemars bails out? This PR adds a custom representation to allow
`"dynamic"` (but no other strings):

This seems like it should work but I don't have a great way to test it.
Closes https://github.com/astral-sh/ruff/issues/9630.
## Summary
Checks for unnecessary `dict` comprehension when creating a new
dictionary from iterable. Suggest to replace with
`dict.fromkeys(iterable)`
See: https://github.com/astral-sh/ruff/issues/9592
## Test Plan
```bash
cargo test
```
## Summary
This PR introduces a new rule to sort `__slots__` and `__match_args__`
according to a [natural sort](https://en.wikipedia.org/wiki/Natural_sort_order), as was
requested in https://github.com/astral-sh/ruff/issues/1198#issuecomment-1881418365.
The implementation here generalises some of the machinery introduced in
3aae16f1bd
so that different kinds of sorts can be applied to lists of string
literals. (We use an "isort-style" sort for `__all__`, but that isn't
really appropriate for `__slots__` and `__match_args__`, where nearly
all items will be snake_case.) Several sections of code have been moved
from `sort_dunder_all.rs` to a new module, `sorting_helpers.rs`, which
`sort_dunder_all.rs` and `sort_dunder_slots.rs` both make use of.
`__match_args__` is very similar to `__all__`, in that it can only be a
tuple or a list. `__slots__` differs from the other two, however, in
that it can be any iterable of strings. If slots is a dictionary, the
values are used by the builtin `help()` function as per-attribute
docstrings that show up in the output of `help()`. (There's no
particular use-case for making `__slots__` a set, but it's perfectly
legal at runtime, so there's no reason for us not to handle it in this
rule.)
Note that we don't do an autofix for multiline `__slots__` if `__slots__` is a dictionary: that's out of scope. Everything else, we can nearly always fix, however.
## Test Plan
`cargo test` / `cargo insta review`.
I also ran this rule on CPython, and the diff looked pretty good
---
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
Implement rule `mutable-fromkeys-value` (`RUF023`).
Autofixes
```python
dict.fromkeys(foo, [])
```
to
```python
{key: [] for key in foo}
```
The fix is marked as unsafe as it changes runtime behaviour. It also
uses `key` as the comprehension variable, which may not always be
desired.
Closes#4613.
## Test Plan
`cargo test`
## Summary
#5920 with a fix for the erroneous slice in `module_name`. Fixes#9547.
## Test Plan
Added `import bbb.ccc._ddd as eee` to the test fixture to ensure it no
longer panics.
`cargo test`
## Summary
This implements the rule proposed in #1198 (though it doesn't close the
issue, as there are some open questions about configuration that might
merit some further discussion).
## Test Plan
`cargo test` / `cargo insta review`. I also ran this PR branch on the CPython
codebase with `--fix --select=RUF022 --preview `, and the results looked
pretty good to me.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Andrew Gallant <andrew@astral.sh>
Implements SIM113 from #998
Added tests
Limitations
- No fix yet
- Only flag cases where index variable immediately precede `for` loop
@charliermarsh please review and let me know any improvements
---------
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
## Summary
Closes#9319, implements the [`SIM911` rule from
`flake8-simplify`](https://github.com/MartinThoma/flake8-simplify/pull/183).
#### Note
I wasn't sure whether or not to include
```rs
if checker.settings.preview.is_disabled() {
return;
}
```
at the beginning of the function with violation logic if the rule's
already declared as part of `RuleGroup::Preview`.
I've seen both variants, so I'd appreciate some feedback on that :)
Fixes#8721
## Summary
This implements the rule proposed in #8721, as RUF021. `and` always
binds more tightly than `or` when chaining the two together.
(This should definitely be autofixable, but I'm leaving that to a
followup PR for now.)
## Test Plan
`cargo test` / `cargo insta review`
## Summary
This PR implements Y058 from flake8-pyi -- this is a new flake8-pyi rule
that was released as part of `flake8-pyi 23.11.0`. I've followed the
Python implementation as closely as possible (see
858c0918a8),
except that for the Ruff version, the rule also applies to `.py` files
as well as for `.pyi` files. (For `.py` files, we only emit the
diagnostic in very specific situations, however, as there's a much
higher likelihood of emitting false positives when applying this rule to
a `.py` file.)
## Test Plan
`cargo test`/`cargo insta review`
## Summary
This PR modifies the semantics of `runtime-evaluated-decorators` to
respect decorators on both classes _and_ functions. Historically, this
only respected classes, since the common use-case is (e.g.)
`pydantic.BaseModel` -- but functions are equally valid.
Closes https://github.com/astral-sh/ruff/issues/9312.
## Test Plan
`cargo test`
## Summary
Part of #970.
This adds Pylint's [R0244
empty_comment](https://pylint.pycqa.org/en/latest/user_guide/messages/refactor/empty-comment.html)
lint as well as an always-safe fix.
## Test Plan
The included snapshot verifies the following:
- A line containing only a non-empty comment is not changed
- A line containing leading whitespace before a non-empty comment is not
changed
- A line containing only an empty comment has its content deleted
- A line containing only leading whitespace before an empty comment has
its content deleted
- A line containing only leading and trailing whitespace on an empty
comment has its content deleted
- A line containing trailing whitespace after a non-empty comment is not
changed
- A line containing only a single newline character (i.e. a blank line)
is not changed
- A line containing code followed by a non-empty comment is not changed
- A line containing code followed by an empty comment has its content
deleted after the last non-whitespace character
- Lines containing code and no comments are not changed
- Empty comment lines within block comments are ignored
- Empty comments within triple-quoted sections are ignored
## Comparison to Pylint
Running Ruff and Pylint 3.0.3 with Python 3.12.0 against the
`empty_comment.py` file added in this PR, we see the following:
* Identical behavior:
* empty_comment.py:3:0: R2044: Line with empty comment (empty-comment)
* empty_comment.py:4:0: R2044: Line with empty comment (empty-comment)
* empty_comment.py:5:0: R2044: Line with empty comment (empty-comment)
* empty_comment.py:18:0: R2044: Line with empty comment (empty-comment)
* Differing behavior:
* Pylint doesn't ignore empty comments in block comments commonly used
for visual spacing; I decided these were fine in this implementation
since many projects use these and likely do not want them removed.
* empty_comment.py:28:0: R2044: Line with empty comment (empty-comment)
* Pylint detects "empty comments" within the triple-quoted section at
the bottom of the file, which is arguably a bug in the Pylint
implementation since these are not truly comments. These are ignored by
this implementation.
* empty_comment.py:37:0: R2044: Line with empty comment (empty-comment)
* empty_comment.py:38:0: R2044: Line with empty comment (empty-comment)
* empty_comment.py:39:0: R2044: Line with empty comment (empty-comment)
## Summary
Adds a rule to detect unions that include `typing.NoReturn` or
`typing.Never`. In such cases, the use of the bottom type is redundant.
Closes https://github.com/astral-sh/ruff/issues/9113.
## Test Plan
`cargo test`
## Summary
A common mistake is to add quotes around one member in an `X | Y`-style
type union, as in:
```python
contract_versions_list: list[ContractVersion] | 'QuerySet[ContractVersion]' | None = None
```
However, doing so will lead to a runtime error if the annotation is
runtime-evaluated. This PR lints against such patterns.
Closes https://github.com/astral-sh/ruff/issues/9139.
This PR does the plumbing to make a new formatting option,
`docstring-code-format`, available in the configuration for end users.
It is disabled by default (opt-in). It is opt-in at least initially to
reflect a conservative posture. The intent is to make it opt-out at some
point in the future.
This was split out from #8811 in order to make #8811 easier to merge.
Namely, once this is merged, docstring code snippet formatting will
become available to end users. (See comments below for how we arrived at
the name.)
Closes#7146
## Test Plan
Other than the standard test suite, I ran the formatter over the CPython
and polars projects to ensure both that the result looked sensible and
that tests still passed. At time of writing, one issue that currently
appears is that reformatting code snippets trips the long line lint:
https://github.com/BurntSushi/polars/actions/runs/7006619426/job/19058868021
## Summary
Adds support for sarif v2.1.0 output to cli, usable via the
output-format paramter.
`ruff . --output-format=sarif`
Includes a few changes I wasn't sure of, namely:
* Adds a few derives for Clone & Copy, which I think could be removed
with a little extra work as well.
## Test Plan
I built and ran this against several large open source projects and
verified that the output sarif was valid, using [Microsoft's SARIF
validator tool](https://sarifweb.azurewebsites.net/Validation)
I've also attached an output of the sarif generated by this version of
ruff on the main branch of django at commit: b287af5dc9
[django_main_b287af5dc9_sarif.json](https://github.com/astral-sh/ruff/files/13626222/django_main_b287af5dc9_sarif.json)
Note: this needs to be regenerated with the latest changes and
confirmed.
## Open Points
[ ] Convert to just using all Rules all the time
[ ] Fix the issue with getting the file URI when compiling for web
assembly
## Summary
This allows us to fix usages like:
```python
from pandas import DataFrame
def baz() -> DataFrame:
...
```
By quoting the `DataFrame` in `-> DataFrame`. Without quotes, moving
`from pandas import DataFrame` into an `if TYPE_CHECKING:` block will
fail at runtime, since Python tries to evaluate the annotation to add it
to the function's `__annotations__`.
Unfortunately, this does require us to split our "annotation kind" flags
into three categories, rather than two:
- `typing-only`: The annotation is only evaluated at type-checking-time.
- `runtime-evaluated`: Python will evaluate the annotation at runtime
(like above) -- but we're willing to quote it.
- `runtime-required`: Python will evaluate the annotation at runtime
(like above), and some library (like Pydantic) needs it to be available
at runtime, so we _can't_ quote it.
This functionality is gated behind a setting
(`flake8-type-checking.quote-annotations`).
Closes https://github.com/astral-sh/ruff/issues/5559.
Hides hints about unsafe fixes when they are disabled e.g. with
`--no-unsafe-fixes` or `unsafe-fixes = false`. By default, unsafe fix
hints are still displayed. This seems like a nice way to remove the nag
for users who have chosen not to apply unsafe fixes.
Inspired by comment at
https://github.com/astral-sh/ruff/issues/9063#issuecomment-1850289675