## Summary
The isolation group for unused imports was relying on
`checker.semantic().current_statement()`, which isn't valid for that
rule, since it runs over the _scope_, not the statement. Instead, we
need to lookup the isolation group based on the `NodeId` of the
statement.
Our tests didn't catch this, because we mostly have cases that look like
this:
```python
if TYPE_CHECKING:
import shelve
import importlib
```
In this case, the two fixes to remove the two unused imports are
considered overlapping (since we delete the _full_ line, and the two
_full_ lines touch, and we consider exactly-adjacent fixes to be
overlapping), and so they don't run in a single pass due to the
non-overlapping-fixes requirement. That is: the isolation groups aren't
required for this case. They are, however, required for cases like:
```python
if TYPE_CHECKING:
import shelve
import importlib
```
...where the fixes don't overlap.
Closes https://github.com/astral-sh/ruff/issues/6758.
## Test Plan
`cargo test`
`IOError` is special, it is not actually a lint but an error before
linting. I'm not entirely sure how to document it since it does not
match the general lint rule pattern (`Checks that the file can be read
in its entirety.` is imho worse).
I added the in my experience two most common reasons for io errors on
unix systems and linked two tutorials on how to fix them.
See https://github.com/astral-sh/ruff/issues/2646
---------
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
## Summary
I noticed this in the ecosystem CI check from
https://github.com/astral-sh/ruff/pull/6742. If we include source code
directly in a diagnostic, we need to be careful to avoid rendering
multi-line diagnostics or even excessively long diagnostics.
## Test Plan
`cargo test`
## Summary
This PR is a follow-up to the suggestion in
https://github.com/astral-sh/ruff/pull/6345#discussion_r1285470953 to
use a single stack to store all statements and expressions, rather than
using separate vectors for each, which gives us something closer to a
full-fidelity chain. (We can then generalize this concept to include all
other AST nodes too.)
This is in part made possible by the removal of the hash map from
`&Stmt` to `StatementId` (#6694), which makes it much cheaper to store
these using a single interface (since doing so no longer introduces the
requirement that we hash all expressions).
I'll follow-up with some profiling, but a few notes on how the data
requirements have changed:
- We now store a `BranchId` for every expression, not just every
statement, so that's an extra `u32`.
- We now store a single `NodeId` on every snapshot, rather than separate
`StatementId` and `ExpressionId` IDs, so that's one fewer `u32` for each
snapshot.
- We're probably doing a few more lookups in general, since any calls to
`current_statement()` etc. now have to iterate up the node hierarchy
until they identify the first statement.
## Test Plan
`cargo test`
## Summary
Avoid attempting to rewrite `import matplotlib.pyplot` as `import
matplotlib.pyplot as plt`. We can't support these right now, since we
don't track references at the attribute level (like
`matplotlib.pyplot`).
Closes https://github.com/astral-sh/ruff/issues/6719.
## Summary
Given:
```python
from sys import *
exit(0)
```
We can't add `exit` to `from sys import *`, so we should just ignore it.
Ideally, we'd just resolve `exit` in the first place (since it's
imported from `from sys import *`), but as long as we don't support
wildcard imports, this is more consistent.
Closes https://github.com/astral-sh/ruff/issues/6718.
## Test Plan
`cargo test`
Avoid the nesting in a macro by using the new `WithNodeLevel` to
`PyFormatter` deref. No changes otherwise.
I wanted to follow this up with quickly fixing the typeshed empty line
rules but they turned out a lot more complex than i had anticipated.
**Summary** A common pattern in the code used to be
```rust
if statements.len() != 1 {
return;
}
use_single_entry(statements[0])?;
```
which can be better expressed as
```rust
let [statement] = statements else {
return;
};
use_single_entry(statements)?;
```
Direct indexing can cause panics if you don't manually take care of
checking the length, while matching (such as if-let or let-else) can
never panic.
This isn't a complete refactor, i've just removed some of the obvious
cases. I've specifically looked for `.len() != 1` and fixed those.
**Test Plan** No functional changes
## Summary
We're using LibCST to ensure that we return the full parenthesized range
of an expression, for display purposes. We can just use
`parenthesized_range` which is more efficient and removes one LibCST
dependency.
## Test Plan
`cargo test`
This _probably_ never matters given the set of rules we support and in
fact I'm having trouble thinking of a test-case for it, but it's
definitely incorrect _not_ to pass on the `BranchId` here.
## Summary
We have a few rules that rely on detecting whether two statements are in
different branches -- for example, different arms of an `if`-`else`.
Historically, the way this was implemented is that, given two statement
IDs, we'd find the common parent (by traversing upwards via our
`Statements` abstraction); then identify branches "manually" by matching
the parents against `try`, `if`, and `match`, and returning iterators
over the arms; then check if there's an arm for which one of the
statements is a child, and the other is not.
This has a few drawbacks:
1. First, the code is generally a bit hard to follow (Konsti mentioned
this too when working on the `ElifElseClause` refactor).
2. Second, this is the only place in the codebase where we need to go
from `&Stmt` to `StatementID` -- _everywhere_ else, we only need to go
in the _other_ direction. Supporting these lookups means we need to
maintain a mapping from `&Stmt` to `StatementID` that includes every
`&Stmt` in the program. (We _also_ end up maintaining a `depth` level
for every statement.) I'd like to get rid of these requirements to
improve efficiency, reduce complexity, and enable us to treat AST modes
more generically in the future. (When I looked at adding the `&Expr` to
our existing statement-tracking infrastructure, maintaining a hash map
with all the statements noticeably hurt performance.)
The solution implemented here instead makes branches a first-class
concept in the semantic model. Like with `Statements`, we now have a
`Branches` abstraction, where each branch points to its optional parent.
When we store statements, we store the `BranchID` alongside each
statement. When we need to detect whether two statements are in the same
branch, we just realize each statement's branch path and compare the
two. (Assuming that the two statements are in the same scope, then
they're on the same branch IFF one branch path is a subset of the other,
starting from the top.) We then add some calls to the visitor to push
and pop branches in the appropriate places, for `if`, `try`, and `match`
statements.
Note that a branch is not 1:1 with a statement; instead, each branch is
closer to a suite, but not _every_ suite is a branch. For example, each
arm in an `if`-`elif`-`else` is a branch, but the `else` in a `for` loop
is not considered a branch.
In addition to being much simpler, this should also be more efficient,
since we've shed the entire `&Stmt` hash map, plus the `depth` that we
track on `StatementWithParent` in favor of a single `Option<BranchID>`
on `StatementWithParent` plus a single vector for all branches. The
lookups should be faster too, since instead of doing a bunch of jumps
around with the hash map + repeated recursive calls to find the common
parents, we instead just do a few simple lookups in the `Branches`
vector to realize and compare the branch paths.
## Test Plan
`cargo test` -- we have a lot of coverage for this, which we inherited
from PyFlakes
## Summary
This is much simpler and avoids (1) multiple passes over the entire
function body, (2) requiring the rule to do its own binding tracking (we
can just use the semantic model), and (3) a usage of `StatementKey`.
In general, where we can, we should try to remove these kinds of custom
visitors that track name references, and instead rely on the semantic
model.
## Test Plan
`cargo test`
## Summary
If a lambda doesn't contain any parameters, or any parameter _tokens_
(like `*`), we can use `None` for the parameters. This feels like a
better representation to me, since, e.g., what should the `TextRange` be
for a non-existent set of parameters? It also allows us to remove
several sites where we check if the `Parameters` is empty by seeing if
it contains any arguments, so semantically, we're already trying to
detect and model around this elsewhere.
Changing this also fixes a number of issues with dangling comments in
parameter-less lambdas, since those comments are now automatically
marked as dangling on the lambda. (As-is, we were also doing something
not-great whereby the lambda was responsible for formatting dangling
comments on the parameters, which has been removed.)
Closes https://github.com/astral-sh/ruff/issues/6646.
Closes https://github.com/astral-sh/ruff/issues/6647.
## Test Plan
`cargo test`
## Summary
In working on https://github.com/astral-sh/ruff/pull/6628, I noticed
that we clone the source code contents, potentially multiple times,
prior to linting. The issue is that `SourceKind::Python` takes a
`String`, so we first have to provide it with a `String`. In the stdin
case, that means cloning. However, on top of this, we then have to clone
`source_kind.contents()` because `SourceKind` gets mutated. So for
stdin, we end up cloning twice. For non-stdin, we end up cloning once,
but unnecessarily (since the _contents_ don't get mutated, only the
kind).
This PR removes the `String` from `source_kind`, instead requiring that
we parse it out elsewhere. It reduces the number of clones down to 1 for
Jupyter Notebooks, and zero otherwise.
