## Summary
Update the name of `ASYNC109` to match
[upstream](https://flake8-async.readthedocs.io/en/latest/rules.html).
Also update to the functionality to match upstream by supporting
additional context managers from `asyncio` and `anyio`. This doesn't
change any of the detection functionality, but recommends additional
context managers from `asyncio` and `anyio` depending on context.
Part of https://github.com/astral-sh/ruff/issues/12039.
## Test Plan
Added fixture for asyncio recommendation
## Summary
Implement mutable-contextvar-default (B039) which was added to
flake8-bugbear in https://github.com/PyCQA/flake8-bugbear/pull/476.
This rule is similar to [mutable-argument-default
(B006)](https://docs.astral.sh/ruff/rules/mutable-argument-default) and
[function-call-in-default-argument
(B008)](https://docs.astral.sh/ruff/rules/function-call-in-default-argument),
except that it checks the `default` keyword argument to
`contextvars.ContextVar`.
```
B039.py:19:26: B039 Do not use mutable data structures for ContextVar defaults
|
18 | # Bad
19 | ContextVar("cv", default=[])
| ^^ B039
20 | ContextVar("cv", default={})
21 | ContextVar("cv", default=list())
|
= help: Replace with `None`; initialize with `.set()` after checking for `None`
```
In the upstream flake8-plugin, this rule is written expressly as a
corollary to B008 and shares much of its logic. Likewise, this
implementation reuses the logic of the Ruff implementation of B008,
namely
f765d19402/crates/ruff_linter/src/rules/flake8_bugbear/rules/function_call_in_argument_default.rs (L104-L106)
and
f765d19402/crates/ruff_linter/src/rules/flake8_bugbear/rules/mutable_argument_default.rs (L106)
Thus, this rule deliberately replicates B006's and B008's heuristics.
For example, this rule assumes that all functions are mutable unless
otherwise qualified. If improvements are to be made to B039 heuristics,
they should probably be made to B006 and B008 as well (whilst trying to
match the upstream implementation).
This rule does not have an autofix as it is unknown where the ContextVar
next used (and it might not be within the same file).
Closes#12054
## Test Plan
`cargo nextest run`
## Summary
This PR ensures that if a variable is bound via `global`, and then the
`global` is read, the originating variable is also marked as read. It's
not perfect, in that it won't detect _rebindings_, like:
```python
from app import redis_connection
def func():
global redis_connection
redis_connection = 1
redis_connection()
```
So, above, `redis_connection` is still marked as unused.
But it does avoid flagging `redis_connection` as unused in:
```python
from app import redis_connection
def func():
global redis_connection
redis_connection()
```
Closes https://github.com/astral-sh/ruff/issues/11518.
## Summary
This PR adds updates the semantic model to detect attribute docstring.
Refer to [PEP 258](https://peps.python.org/pep-0258/#attribute-docstrings)
for the definition of an attribute docstring.
This PR doesn't add full support for it but only considers string
literals as attribute docstring for the following cases:
1. A string literal following an assignment statement in the **global
scope**.
2. A global class attribute
For an assignment statement, it's considered an attribute docstring only
if the target expression is a name expression (`x = 1`). So, chained
assignment, multiple assignment or unpacking, and starred expression,
which are all valid in the target position, aren't considered here.
In `__init__` method, an assignment to the `self` variable like `self.x = 1`
is also a candidate for an attribute docstring. **This PR does not
support this position.**
## Test Plan
I used the following source code along with a print statement to verify
that the attribute docstring detection is correct.
Refer to the PR description for the code snippet.
I'll add this in the follow-up PR
(https://github.com/astral-sh/ruff/pull/11302) which uses this method.
## Summary
If the user is analyzing a script (i.e., we have no module path), it
seems reasonable to use the script name when trying to identify paths to
objects defined _within_ the script.
Closes https://github.com/astral-sh/ruff/issues/10960.
## Test Plan
Ran:
```shell
check --isolated --select=B008 \
--config 'lint.flake8-bugbear.extend-immutable-calls=["test.A"]' \
test.py
```
On:
```python
class A: pass
def f(a=A()):
pass
```
## Summary
Fixes#3011.
Type checkers currently allow forward references in all contexts in stub
files, and stubs frequently make use of this capability (although it
doesn't actually seem to be specc'd anywhere --neither in PEP 484, nor
https://typing.readthedocs.io/en/latest/source/stubs.html#id6, nor the
CPython typing docs). Implementing it so that Ruff allows forward
references in _all contexts_ in stub files seems non-trivial, however
(or at least, I couldn't figure out how to do it easily), so this PR
does not do that. Perhaps it _should_; if we think this apporach isn't
principled enough, I'm happy to close it and postpone changing anything
here.
However, this does reduce the number of F821 errors Ruff emits on
typeshed down from 76 to 2, which would mean that we could enable the
rule at typeshed. The remaining 2 F821 errors can be trivially fixed at
typeshed by moving definitions around; forward references in class bases
were really the only remaining places where there was a real _use case_
for forward references in stub files that Ruff wasn't yet allowing.
## Test plan
`cargo test`. I also ran this PR branch on typeshed to check to see if
there were any new false positives caused by the changes here; there
were none.
## Summary
This PR adds a new semantic model flag to indicate that the checker is
inside an f-string replacement field. This will be used to ignore
certain checks if the target version doesn't support a specific feature
like PEP 701.
fixes: #10761
## Test Plan
Add a test case from the raised issue.
## Summary
In https://github.com/astral-sh/ruff/pull/10341, we fixed some false
positives in `.pyi` files, but introduced others. This PR effectively
reverts the change in #10341 and fixes it in a slightly different way.
Instead of changing the _bindings_ we generate in the semantic model in
`.pyi` files, we instead change how we _resolve_ them.
Closes https://github.com/astral-sh/ruff/issues/10509.
## Summary
Given `del X`, we'll typically add a `BindingKind::Deletion` to `X` to
shadow the current binding. However, if the deletion is inside of a
conditional operation, we _won't_, as in:
```python
def f():
global X
if X > 0:
del X
```
We will, however, track it as a reference to the binding. This PR adds
the expression context to those resolved references, so that we can
detect that the `X` in `global X` was "assigned to".
Closes https://github.com/astral-sh/ruff/issues/10397.
## Summary
When you try to remove an internal representation leaking into another
type and end up rewriting a simple version of `smallvec`.
The goal of this PR is to replace the `Box<[&'a str]>` with
`Box<QualifiedName>` to avoid that the internal `QualifiedName`
representation leaks (and it gives us a nicer API too). However, doing
this when `QualifiedName` uses `SmallVec` internally gives us all sort
of funny lifetime errors. I was lost but @BurntSushi came to rescue me.
He figured out that `smallvec` has a variance problem which is already
tracked in https://github.com/servo/rust-smallvec/issues/146
To fix the variants problem, I could use the smallvec-2-alpha-4 or
implement our own smallvec. I went with implementing our own small vec
for this specific problem. It obviously isn't as sophisticated as
smallvec (only uses safe code), e.g. it doesn't perform any size
optimizations, but it does its job.
Other changes:
* Removed `Imported::qualified_name` (the version that returns a
`String`). This can be replaced by calling `ToString` on the qualified
name.
* Renamed `Imported::call_path` to `qualified_name` and changed its
return type to `&QualifiedName`.
* Renamed `QualifiedName::imported` to `user_defined` which is the more
common term when talking about builtins vs the rest/user defined
functions.
## Test plan
`cargo test`
## Summary
Charlie can probably explain this better than I but it turns out,
`CallPath` is used for two different things:
* To represent unqualified names like `version` where `version` can be a
local variable or imported (e.g. `from sys import version` where the
full qualified name is `sys.version`)
* To represent resolved, full qualified names
This PR splits `CallPath` into two types to make this destinction clear.
> Note: I haven't renamed all `call_path` variables to `qualified_name`
or `unqualified_name`. I can do that if that's welcomed but I first want
to get feedback on the approach and naming overall.
## Test Plan
`cargo test`
## Summary
This PR changes the `CallPath` type alias to a newtype wrapper.
A newtype wrapper allows us to limit the API and to experiment with
alternative ways to implement matching on `CallPath`s.
## Test Plan
`cargo test`
## Summary
This PR introduces a new semantic model flag `DOCSTRING` which suggests
that the model is currently in a module / class / function docstring.
This is the first step in eliminating the docstring detection state
machine which is prone to bugs as stated in #7595.
## Test Plan
~TODO: Is there a way to add a test case for this?~
I tested this using the following code snippet and adding a print
statement in the `string_like` analyzer to print if we're currently in a
docstring or not.
<details><summary>Test code snippet:</summary>
<p>
```python
"Docstring" ", still a docstring"
"Not a docstring"
def foo():
"Docstring"
"Not a docstring"
if foo:
"Not a docstring"
pass
class Foo:
"Docstring"
"Not a docstring"
foo: int
"Unofficial variable docstring"
def method():
"Docstring"
"Not a docstring"
pass
def bar():
"Not a docstring".strip()
def baz():
_something_else = 1
"""Not a docstring"""
```
</p>
</details>
## Summary
I was surprised to learn that we treat `x` in `[_ for x in y]` as an
"assignment" binding kind, rather than a dedicated comprehension
variable.
## Summary
This PR renames the semantic model flag `MODULE_DOCSTRING` to
`MODULE_DOCSTRING_BOUNDARY`. The main reason is for readability and for
the new semantic model flag `DOCSTRING` which tracks that the model is
in a module / class / function docstring.
I got confused earlier with the name until I looked at the use case and
it seems that the `_BOUNDARY` prefix is more appropriate for the
use-case and is consistent with other flags.
## Summary
This is a simple idea to avoid unnecessary work in the linter,
especially for rules that run on all name and/or all attribute nodes.
Imagine a rule like the NumPy deprecation check. If the user never
imported `numpy`, we should be able to skip that rule entirely --
whereas today, we do a `resolve_call_path` check on _every_ name in the
file. It turns out that there's basically a finite set of modules that
we care about, so we now track imports on those modules as explicit
flags on the semantic model. In rules that can _only_ ever trigger if
those modules were imported, we add a dedicated and extremely cheap
check to the top of the rule.
We could consider generalizing this to all modules, but I would expect
that not to be much faster than `resolve_call_path`, which is just a
hash map lookup on `TextSize` anyway.
It would also be nice to make this declarative, such that rules could
declare the modules they care about, the analyzers could call the rules
as appropriate. But, I don't think such a design should block merging
this.
## Summary
This PR attempts to improve `builtin-attribute-shadowing` (`A003`), a
rule which has been repeatedly criticized, but _does_ have value (just
not in the current form).
Historically, this rule would flag cases like:
```python
class Class:
id: int
```
This led to an increasing number of exceptions and special-cases to the
rule over time to try and improve it's specificity (e.g., ignore
`TypedDict`, ignore `@override`).
The crux of the issue is that given the above, referencing `id` will
never resolve to `Class.id`, so the shadowing is actually fine. There's
one exception, however:
```python
class Class:
id: int
def do_thing() -> id:
pass
```
Here, `id` actually resolves to the `id` attribute on the class, not the
`id` builtin.
So this PR completely reworks the rule around this _much_ more targeted
case, which will almost always be a mistake: when you reference a class
member from within the class, and that member shadows a builtin.
Closes https://github.com/astral-sh/ruff/issues/6524.
Closes https://github.com/astral-sh/ruff/issues/7806.
## Summary
On `main`, we flag redefinitions in cases like:
```python
import os
x = 1
if x > 0:
import os
```
That is, we consider these to be in the "same branch", since they're not
in disjoint branches. This matches Flake8's behavior, but it seems to
lead to false positives.
## Summary
Historically, we encoded this list by extracting the `__all__`. I went
to update it, but... is there really any value in it? Seems easier to
just treat `typing_extensions` as an alias for `typing`.
Closes https://github.com/astral-sh/ruff/issues/9334.
## 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.
This PR renames the semantic model flag `LITERAL` to `TYPING_LITERAL` to
better reflect its purpose. The main motivation behind this change is to
avoid any confusion with the "literal" terminology used in the AST for
literal nodes like string, bytes, numbers, etc.
~Improves detection of types imported from `typing_extensions`. Removes
the hard-coded list of supported types in `typing_extensions`; instead
assuming all types could be imported from `typing`, `_typeshed`, or
`typing_extensions`.~
~The typing extensions package appears to re-export types even if they
do not need modification.~
Adds detection of `if typing_extensions.TYPE_CHECKING` blocks. Avoids
inserting a new `if TYPE_CHECKING` block and `from typing import
TYPE_CHECKING` if `typing_extensions.TYPE_CHECKING` is used (closes
https://github.com/astral-sh/ruff/issues/8427)
---------
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
## Summary
We have this pattern in a bunch of places, where we find the _only_
binding to a name (and return `None`) if it's bound multiple times. This
PR DRYs it up into a method on `SemanticModel`.
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## Summary
In https://github.com/astral-sh/ruff/pull/7968, I introduced a
regression whereby we started to treat imports used _only_ in type
annotation bounds (with `__future__` annotations) as unused.
The root of the issue is that I started using `visit_annotation` for
these bounds. So we'd queue up the bound in the list of deferred type
parameters, then when visiting, we'd further queue it up in the list of
deferred type annotations... Which we'd then never visit, since deferred
type annotations are visited _before_ deferred type parameters.
Anyway, the better solution here is to use a dedicated flag for these,
since they have slightly different behavior than type annotations.
I've also fixed what I _think_ is a bug whereby we previously failed to
resolve `Callable` in:
```python
type RecordCallback[R: Record] = Callable[[R], None]
from collections.abc import Callable
```
IIUC, the values in type aliases should be evaluated lazily, like type
parameters.
Closes https://github.com/astral-sh/ruff/issues/8017.
## Test Plan
`cargo test`
## Summary
This wasn't necessary in the past, since we _only_ applied this rule to
bodies that contained two statements, one of which was a `pass`. Now
that it applies to any `pass` in a block with multiple statements, we
can run into situations in which we remove both passes, and so need to
apply the fixes in isolation.
See:
https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741107573.
