## Summary
* Support assignments to attributes in more cases:
- assignments in `for` loops
- in unpacking assignments
* Add test for multi-target assignments
* Add tests for all other possible assignments to attributes that could
possibly occur (in decreasing order of likeliness):
- augmented attribute assignments
- attribute assignments in `with` statements
- attribute assignments in comprehensions
- Note: assignments to attributes in named expressions are not
syntactically allowed
closes#15962
## Test Plan
New Markdown tests
## Summary
This PR reverts the behavior changes from
https://github.com/astral-sh/ruff/pull/15990
But it isn't just a revert, it also:
* Adds a test covering this specific behavior
* Preserves the improvement to use `saturating_sub` in the package case
to avoid overflows in the case of invalid syntax
* Use `ancestors` instead of a `for` loop
## Test Plan
Added test
## Summary
Adds a JSON schema generation step for Red Knot. This PR doesn't yet add
a publishing step because it's still a bit early for that
## Test plan
I tested the schema in Zed, VS Code and PyCharm:
* PyCharm: You have to manually add a schema mapping (settings JSON
Schema Mappings)
* Zed and VS code support the inline schema specification
```toml
#:schema /Users/micha/astral/ruff/knot.schema.json
[environment]
extra-paths = []
[rules]
call-possibly-unbound-method = "error"
unknown-rule = "error"
# duplicate-base = "error"
```
```json
{
"$schema": "file:///Users/micha/astral/ruff/knot.schema.json",
"environment": {
"python-version": "3.13",
"python-platform": "linux2"
},
"rules": {
"unknown-rule": "error"
}
}
```
https://github.com/user-attachments/assets/a18fcd96-7cbe-4110-985b-9f1935584411
The Schema overall works but all editors have their own quirks:
* PyCharm: Hovering a name always shows the section description instead
of the description of the specific setting. But it's the same for other
settings in `pyproject.toml` files 🤷
* VS Code (JSON): Using the generated schema in a JSON file gives
exactly the experience I want
* VS Code (TOML):
* Properties with multiple possible values are repeated during
auto-completion without giving any hint how they're different. 
* The property description mushes together the description of the
property and the value, which looks sort of ridiculous. 
* Autocompletion and documentation hovering works (except the
limitations mentioned above)
* Zed:
* Very similar to VS Code with the exception that it uses the
description attribute to distinguish settings with multiple possible
values 
I don't think there's much we can do here other than hope (or help)
editors improve their auto completion. The same short comings also apply
to ruff, so this isn't something new. For now, I think this is good
enough
## Summary
Part of #15809 and #15876.
This change brings several bugfixes:
* The nested `map()` call in `list(map(lambda x: x, []))` where `list`
is overshadowed is now correctly reported.
* The call will no longer reported if:
* Any arguments given to `map()` are variadic.
* Any of the iterables contain a named expression.
## Test Plan
`cargo nextest run` and `cargo insta test`.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
This change resolves#15814 to ensure that `SIM401` is only triggered on
known dictionary types. Before, the rule was getting triggered even on
types that _resemble_ a dictionary but are not actually a dictionary.
I did this using the `is_known_to_be_of_type_dict(...)` functionality.
The logic for this function was duplicated in a few spots, so I moved
the code to a central location, removed redundant definitions, and
updated existing calls to use the single definition of the function!
## Test Plan
Since this PR only modifies an existing rule, I made changes to the
existing test instead of adding new ones. I made sure that `SIM401` is
triggered on types that are clearly dictionaries and that it's not
triggered on a simple custom dictionary-like type (using a modified
version of [the code in the issue](#15814))
The additional changes to de-duplicate `is_known_to_be_of_type_dict`
don't break any existing tests -- I think this should be fine since the
logic remains the same (please let me know if you think otherwise, I'm
excited to get feedback and work towards a good fix 🙂).
---------
Co-authored-by: Junhson Jean-Baptiste <junhsonjb@naan.mynetworksettings.com>
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
Resolves#15997.
Ruff used to introduce syntax errors while fixing these cases, but no
longer will:
```python
{"a": [], **{},}
# ^^^^ Removed, leaving two contiguous commas
{"a": [], **({})}
# ^^^^^ Removed, leaving a stray closing parentheses
```
Previously, the function would take a shortcut if the unpacked
dictionary is empty; now, both cases are handled using the same logic
introduced in #15394. This change slightly modifies that logic to also
remove the first comma following the dictionary, if and only if it is
empty.
## Test Plan
`cargo nextest run` and `cargo insta test`.
## Summary
Fixes https://github.com/astral-sh/ruff/issues/15978
Even Better TOML doesn't support `allOf` well. In fact, it just crashes.
This PR works around this limitation by avoid using `allOf` in the
automatically
derived schema for the docstring formatting setting.
### Alternatives
schemars introduces `allOf` whenver it sees a `$ref` alongside other
object properties
because this is no longer valid according to Draft 7. We could replace
the
visitor performing the rewrite but I prefer not to because replacing
`allOf` with `oneOf`
is only valid for objects that don't have any other `oneOf` or `anyOf`
schema.
## Test Plan
https://github.com/user-attachments/assets/25d73b2a-fee1-4ba6-9ffe-869b2c3bc64e
## Summary
I noticed that the diagnostic range in specific unpacking assignments is
wrong. For this example
```py
a, b = 1
```
we previously got (see first commit):
```
error: lint:not-iterable
--> /src/mdtest_snippet.py:1:1
|
1 | a, b = 1
| ^^^^ Object of type `Literal[1]` is not iterable
|
```
and with this change, we get:
```
error: lint:not-iterable
--> /src/mdtest_snippet.py:1:8
|
1 | a, b = 1
| ^ Object of type `Literal[1]` is not iterable
|
```
## Test Plan
New snapshot tests.
## Summary
Fixes https://github.com/astral-sh/ruff/issues/15989
Red Knot failed to resolve relative imports if the importing module is
located at a search path root.
The issue was that the module resolver returned an `Err(TooManyDots)` as
soon as the parent of the current module is `None` (which is the case
for a module at the search path root).
However, this is incorrect if a `tail` (a module name) exists.
Closes#15681
## Summary
This changes `analyze::typing::is_type_checking_block` to recognize all
symbols named "TYPE_CHECKING".
This matches the current behavior of mypy and pyright as well as
`flake8-type-checking`.
It also drops support for detecting `if False:` and `if 0:` as type
checking blocks. This used to be an option for
providing backwards compatibility with Python versions that did not have
a `typing` module, but has since
been removed from the typing spec and is no longer supported by any of
the mainstream type checkers.
## Test Plan
`cargo nextest run`
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
- Minor wording update
- Code improvement (thanks Alex)
- Removed all unnecessary filenames throughout our Markdown tests (two
new ones were added in the meantime)
- Minor rewording of the statically-known-branches introduction
This example from @sharkdp shows how terminal statements can appear in
statically known branches:
https://github.com/astral-sh/ruff/pull/15676#issuecomment-2618809716
```py
def _(cond: bool):
x = "a"
if cond:
x = "b"
if True:
return
reveal_type(x) # revealed: "a", "b"; should be "a"
```
We now use visibility constraints to track reachability, which allows us
to model this correctly. There are two related changes as a result:
- New bindings are not assumed to be visible; they inherit the current
"scope start" visibility, which effectively means that new bindings are
visible if/when the current flow is reachable
- When simplifying visibility constraints after branching control flow,
we only simplify if none of the intervening branches included a terminal
statement. That is, earlier unaffected bindings are only _actually_
unaffected if all branches make it to the merge point.
## Summary
Allow for literate style in Markdown tests and merge multiple (unnamed)
code blocks into a single embedded file.
closes#15941
## Test Plan
- Interactively made sure that error-lines were reported correctly in
multi-snippet sections.
This causes the diagnostic to highlight the actual unresovable import
instead of the entire `from ... import ...` statement.
While we're here, we expand the test coverage to cover all of the
possible ways that an `import` or a `from ... import` can fail.
Some considerations:
* The first commit in this PR adds a regression test for the current
behavior.
* This creates a new `mdtest/diagnostics` directory. Are folks cool
with this? I guess the idea is to put tests more devoted to diagnostics
than semantics in this directory. (Although I'm guessing there will
be some overlap.)
Fixes#15866
## Summary
This is a first step towards creating a test suite for
[descriptors](https://docs.python.org/3/howto/descriptor.html). It does
not (yet) aim to be exhaustive.
relevant ticket: #15966
## Test Plan
Compared desired behavior with the runtime behavior and the behavior of
existing type checkers.
---------
Co-authored-by: Mike Perlov <mishamsk@gmail.com>
This ties together everything from the previous commits.
Some interesting bits here are how the snapshot is generated
(where we include relevant info to make it easier to review
the snapshots) and also a tweak to how inline assertions are
processed.
This commit also includes some example snapshots just to get
a sense of what they look like. Follow-up work should add
more of these I think.
I split this out into a separate commit and put it here
so that reviewers can get a conceptual model of what the
code is doing before seeing the code. (Hopefully that helps.)
This makes it possible for callers to set where snapshots
should be stored. In general, I think we expect this to
always be set, since otherwise snapshots will end up in
`red_knot_test`, which is where the tests are actually run.
But that's overall counter-intuitive. This permits us to
store snapshots from mdtests alongside the mdtests themselves.
I found it useful to have the `&dyn Diagnostic` trait impl
specifically. I added `Arc<dyn Diagnostic>` for completeness.
(I do kind of wonder if we should be preferring `Arc<dyn ...>`
over something like `Box<dyn ...>` more generally, especially
for things with immutable APIs. It would make cloning cheap.)
This change was done to reduce snapshot churn. Previously,
if one added a new section to an Markdown test suite, then
the snapshots of all sections with unnamed files below it would
necessarily change because of the unnamed file count being
global to the test suite.
Instead, we track counts based on section. While adding new
unnamed files within a section will still change unnamed
files below it, I believe this will be less "churn" because
the snapshot will need to change anyway. Some churn is still
possible, e.g., if code blocks are re-ordered. But I think this
is an acceptable trade-off.
## Summary
Minor docs follow-up to #15862 to mention UP049 in the UP046 and UP047
`See also` sections. I wanted to mention it in UP040 too but realized it
didn't have a `See also` section, so I also added that, adapted from the
other two rules.
## Test Plan
cargo test
## Summary
The PR addresses the issue #15887
For two objects `a` and `b`, we ensure that the auto-fix and the
suggestion is of the form `a = min(a, b)` (or `a = max(a, b)`). This is
because we want to be consistent with the python implementation of the
methods: `min` and `max`. See the above issue for more details.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
Resolves#15936.
The fixes will now attempt to preserve the original iterable's format
and quote it if necessary. For `FURB142`, comments within the fix range
will make it unsafe as well.
## Test Plan
`cargo nextest run` and `cargo insta test`.
## Summary
Resolves#15863.
In preview, diagnostic ranges will now be limited to that of the
argument. Rule documentation, variable names, error messages and fix
titles have all been modified to use "argument" consistently.
## Test Plan
`cargo nextest run` and `cargo insta test`.
## Summary
Resolves#15925.
`N803` now checks for functions instead of parameters. In preview mode,
if a method is decorated with `@override` and the current scope is that
of a class, it will be ignored.
## Test Plan
`cargo nextest run` and `cargo insta test`.
## Summary
Follow-up to #15779.
Prior to this change, non-name expressions are not reported at all:
```python
type(a.b) is type(None) # no error
```
This change enhances the rule so that such cases are also reported in
preview. Additionally:
* The fix will now be marked as unsafe if there are any comments within
its range.
* Error messages are slightly modified.
## Test Plan
`cargo nextest run` and `cargo insta test`.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Previously an error was emitted any time the configuration required both
an import of a module and an alias for that module. However, required
imports could themselves contain an alias, which may or may not agree
with the required alias.
To wit: requiring `import pandas as pd` does not conflict with the
`flake8-import-conventions.alias` config `{"pandas":"pd"}`.
This PR refines the check before throwing an error.
Closes#15911
## Summary
This PR adds `Type::call_bound` method for calls that should follow
descriptor protocol calling convention. The PR is intentionally shallow
in scope and only fixes#15672
Couple of obvious things that weren't done:
* Switch to `call_bound` everywhere it should be used
* Address the fact, that red_knot resolves `__bool__ = bool` as a Union,
which includes `Type::Dynamic` and hence fails to infer that the
truthiness is always false for such a class (I've added a todo comment
in mdtests)
* Doesn't try to invent a new type for descriptors, although I have a
gut feeling it may be more convenient in the end, instead of doing
method lookup each time like I did in `call_bound`
## Test Plan
* extended mdtests with 2 examples from the issue
* cargo neatest run
We now use ternary decision diagrams (TDDs) to represent visibility
constraints. A TDD is just like a BDD ([_binary_ decision
diagram](https://en.wikipedia.org/wiki/Binary_decision_diagram)), but
with "ambiguous" as an additional allowed value. Unlike the previous
representation, TDDs are strongly normalizing, so equivalent ternary
formulas are represented by exactly the same graph node, and can be
compared for equality in constant time.
We currently have a slight 1-3% performance regression with this in
place, according to local testing. However, we also have a _5× increase_
in performance for pathological cases, since we can now remove the
recursion limit when we evaluate visibility constraints.
As follow-on work, we are now closer to being able to remove the
`simplify_visibility_constraint` calls in the semantic index builder. In
the vast majority of cases, we now see (for instance) that the
visibility constraint after an `if` statement, for bindings of symbols
that weren't rebound in any branch, simplifies back to `true`. But there
are still some cases we generate constraints that are cyclic. With
fixed-point cycle support in salsa, or with some careful analysis of the
still-failing cases, we might be able to remove those.
## Summary
This is a new rule to implement the renaming of PEP 695 type parameters
with leading underscores after they have (presumably) been converted
from standalone type variables by either UP046 or UP047. Part of #15642.
I'm not 100% sure the fix is always safe, but I haven't come up with any
counterexamples yet. `Renamer` seems pretty precise, so I don't think
the usual issues with comments apply.
I initially tried writing this as a rule that receives a `Stmt` rather
than a `Binding`, but in that case the
`checker.semantic().current_scope()` was the global scope, rather than
the scope of the type parameters as I needed. Most of the other rules
using `Renamer` also used `Binding`s, but it does have the downside of
offering separate diagnostics for each parameter to rename.
## Test Plan
New snapshot tests for UP049 alone and the combination of UP046, UP049,
and PYI018.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
I experimented with [not trimming trailing newlines in code
snippets](https://github.com/astral-sh/ruff/pull/15926#discussion_r1940992090),
but since came to the conclusion that the current behavior is better
because otherwise, there is no way to write snippets without a trailing
newline at all. And when you copy the code from a Markdown snippet in
GitHub, you also don't get a trailing newline.
I was surprised to see some test failures when I played with this
though, and decided to make this test independent from this
implementation detail.
