## Summary
The `operator.itemgetter` behavior changes where there's more than one
argument, such that `operator.itemgetter(0)` yields `r[0]`, rather than
`(r[0],)`.
Closes https://github.com/astral-sh/ruff/issues/11075.
Resolves#10187
<details>
<summary>Old PR description; accurate through commit e86dd7d; probably
best to leave this fold closed</summary>
## Description of change
In the case of a printf-style format string with only one %-placeholder
and a variable at right (e.g. `"%s" % var`):
* The new behavior attempts to dereference the variable and then match
on the bound expression to distinguish between a 1-tuple (fix), n-tuple
(bug 🐛), or a non-tuple (fix). Dereferencing is via
`analyze::typing::find_binding_value`.
* If the variable cannot be dereferenced, then the type-analysis routine
is called to distinguish only tuple (no-fix) or non-tuple (fix). Type
analysis is via `analyze::typing::is_tuple`.
* If any of the above fails, the rule still fires, but no fix is
offered.
## Alternatives
* If the reviewers think that singling out the 1-tuple case is too
complicated, I will remove that.
* The ecosystem results show that no new fixes are detected. So I could
probably delete all the variable dereferencing code and code that tries
to generate fixes, tbh.
## Changes to existing behavior
**All the previous rule-firings and fixes are unchanged except for** the
"false negatives" in
`crates/ruff_linter/resources/test/fixtures/pyupgrade/UP031_1.py`. Those
previous "false negatives" are now true positives and so I moved them to
`crates/ruff_linter/resources/test/fixtures/pyupgrade/UP031_0.py`.
<details>
<summary>Existing false negatives that are now true positives</summary>
```
crates/ruff_linter/resources/test/fixtures/pyupgrade/UP031_0.py:134:1: UP031 Use format specifiers instead of percent format
|
133 | # UP031 (no longer false negatives)
134 | 'Hello %s' % bar
| ^^^^^^^^^^^^^^^^ UP031
135 |
136 | 'Hello %s' % bar.baz
|
= help: Replace with format specifiers
crates/ruff_linter/resources/test/fixtures/pyupgrade/UP031_0.py:136:1: UP031 Use format specifiers instead of percent format
|
134 | 'Hello %s' % bar
135 |
136 | 'Hello %s' % bar.baz
| ^^^^^^^^^^^^^^^^^^^^ UP031
137 |
138 | 'Hello %s' % bar['bop']
|
= help: Replace with format specifiers
crates/ruff_linter/resources/test/fixtures/pyupgrade/UP031_0.py:138:1: UP031 Use format specifiers instead of percent format
|
136 | 'Hello %s' % bar.baz
137 |
138 | 'Hello %s' % bar['bop']
| ^^^^^^^^^^^^^^^^^^^^^^^ UP031
|
= help: Replace with format specifiers
```
One of them newly offers a fix.
```
# UP031 (no longer false negatives)
-'Hello %s' % bar
+'Hello {}'.format(bar)
```
This fix occurs because the new code dereferences `bar` to where it was
defined earlier in the file as a non-tuple:
```python
bar = {"bar": y}
```
---
</details>
## Behavior requiring new tests
Additionally, we now handle a few cases that we didn't previously test.
These cases are when a string has a single %-placeholder and the
righthand operand to the modulo operator is a variable **which can be
dereferenced.** One of those was shown in the previous section (the
"dereference non-tuple" case).
<details>
<summary>New cases handled</summary>
```
crates/ruff_linter/resources/test/fixtures/pyupgrade/UP031_0.py:126:1: UP031 [*] Use format specifiers instead of percent format
|
125 | t1 = (x,)
126 | "%s" % t1
| ^^^^^^^^^ UP031
127 | # UP031: deref t1 to 1-tuple, offer fix
|
= help: Replace with format specifiers
crates/ruff_linter/resources/test/fixtures/pyupgrade/UP031_0.py:130:1: UP031 Use format specifiers instead of percent format
|
129 | t2 = (x,y)
130 | "%s" % t2
| ^^^^^^^^^ UP031
131 | # UP031: deref t2 to n-tuple, this is a bug
|
= help: Replace with format specifiers
```
One of these offers a fix.
```
t1 = (x,)
-"%s" % t1
+"{}".format(t1[0])
# UP031: deref t1 to 1-tuple, offer fix
```
The other doesn't offer a fix because it's a bug.
---
</details>
---
</details>
## Changes to existing behavior
In the case of a string with a single %-placeholder and a single
ambiguous righthand argument to the modulo operator, (e.g. `"%s" % var`)
the rule now fires and offers a fix. We explain about this in the "fix
safety" section of the updated documentation.
## Documentation changes
I swapped the order of the "known problems" and the "examples" sections
so that the examples which describe the rule are first, before the
exceptions to the rule are described. I also tweaked the language to be
more explicit, as I had trouble understanding the documentation at
first. The "known problems" section is now "fix safety" but the content
is largely similar.
The diff of the documentation changes looks a little difficult unless
you look at the individual commits.
Add pylint rule invalid-hash-returned (PLE0309)
See https://github.com/astral-sh/ruff/issues/970 for rules
Test Plan: `cargo test`
TBD: from the description: "Strictly speaking `bool` is a subclass of
`int`, thus returning `True`/`False` is valid. To be consistent with
other rules (e.g.
[PLE0305](https://github.com/astral-sh/ruff/pull/10962)
invalid-index-returned), ruff will raise, compared to pylint which will
not raise."
Add pylint rule invalid-length-returned (PLE0303)
See https://github.com/astral-sh/ruff/issues/970 for rules
Test Plan: `cargo test`
TBD: from the description: "Strictly speaking `bool` is a subclass of
`int`, thus returning `True`/`False` is valid. To be consistent with
other rules (e.g.
[PLE0305](https://github.com/astral-sh/ruff/pull/10962)
invalid-index-returned), ruff will raise, compared to pylint which will
not raise."
## 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
This change adds a rule to detect functions declared `async` but lacking
any of `await`, `async with`, or `async for`. This resolves#9951.
## Test Plan
This change was tested by following
https://docs.astral.sh/ruff/contributing/#rule-testing-fixtures-and-snapshots
and adding positive and negative cases for each of `await` vs nothing,
`async with` vs `with`, and `async for` vs `for`.
## Summary
Adds more aggressive logic to PLR1730, `if-stmt-min-max`
Closes#10907
## Test Plan
`cargo test`
---------
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
## Summary
If `RUF100` was included in a per-file-ignore, we respected it on cases
like `# noqa: F401`, but not the blanket variant (`# noqa`).
Closes https://github.com/astral-sh/ruff/issues/10906.
## Summary
Implement new rule: Prefer augmented assignment (#8877). It checks for
the assignment statement with the form of `<expr> = <expr>
<binary-operator> …` with a unsafe fix to use augmented assignment
instead.
## Test Plan
1. Snapshot test is included in the PR.
2. Manually test with playground.
## Summary
This PR adds the implementation for the current
[flake8-bugbear](https://github.com/PyCQA/flake8-bugbear)'s B038 rule.
The B038 rule checks for mutation of loop iterators in the body of a for
loop and alerts when found.
Rational:
Editing the loop iterator can lead to undesired behavior and is probably
a bug in most cases.
Closes#9511.
Note there will be a second iteration of B038 implemented in
`flake8-bugbear` soon, and this PR currently only implements the weakest
form of the rule.
I'd be happy to also implement the further improvements to B038 here in
ruff 🙂
See https://github.com/PyCQA/flake8-bugbear/issues/454 for more
information on the planned improvements.
## Test Plan
Re-using the same test file that I've used for `flake8-bugbear`, which
is included in this PR (look for the `B038.py` file).
Note: this is my first time using `rust` (beside `rustlings`) - I'd be
very happy about thorough feedback on what I could've done better
🙂 - Bring it on 😀
## Summary
Implement `write-whole-file` (`FURB103`), part of #1348. This is largely
a copy and paste of `read-whole-file` #7682.
## Test Plan
Text fixture added.
---------
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
## Summary
Improve `blanket-noqa` error message in cases where codes are provided
but not detected due to formatting issues. Namely `# noqa X100` (missing
colon) or `noqa : X100` (space before colon). The behavior is similar to
`NQA002` and `NQA003` from `flake8-noqa` mentioned in #850. The idea to
merge the rules into `PGH004` was suggested by @MichaReiser
https://github.com/astral-sh/ruff/pull/10325#issuecomment-2025535444.
## Test Plan
Test cases added to fixture.
## 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
`Path.read_bytes()` does not support any keyword arguments, so `FURB101`
should not be triggered if the file is opened in `rb` mode with any
keyword arguments.
## Test Plan
Move erroneous test to "Non-error" section of fixture.
## Summary
Historically, given:
```python
__all__ = [ # noqa: F822
"Bernoulli",
"Beta",
"Binomial",
]
```
The F822 violations would be attached to the `__all__`, so this `# noqa`
would be enforced for _all_ definitions in the list. This changed in
https://github.com/astral-sh/ruff/pull/10525 for the better, in that we
now use the range of each string. But these `# noqa` directives stopped
working.
This PR sets the `__all__` as a parent range in the diagnostic, so that
these directives are respected once again.
Closes https://github.com/astral-sh/ruff/issues/10795.
## Test Plan
`cargo test`
## Summary
Add new rule `pyupgrade - UP042` (I picked next available number).
Closes https://github.com/astral-sh/ruff/discussions/3867
Closes https://github.com/astral-sh/ruff/issues/9569
It should warn + provide a fix `class A(str, Enum)` -> `class
A(StrEnum)` for py311+.
## Test Plan
Added UP042.py test.
## Notes
I did not find a way to call `remove_argument` 2 times consecutively, so
the automatic fixing works only for classes that inherit exactly `str,
Enum` (regardless of the order).
I also plan to extend this rule to support IntEnum in next PR.
## 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.
Fixes#3259
## Summary
Renames `UnnecessaryComprehensionAnyAll` to
`UnnecessaryComprehensionInCall` and extends the check to `sum`, `min`,
and `max`, in addition to `any` and `all`.
## Test Plan
Updated snapshot test.
Built docs locally and verified the docs for this rule still render
correctly.
## Summary
We lost the per-rule ignores when these were migrated to the AST, so if
_any_ `Q` rule is enabled, they're now all enabled.
Closes https://github.com/astral-sh/ruff/issues/10724.
## Test Plan
Ran:
```shell
ruff check . --isolated --select Q --ignore Q000
ruff check . --isolated --select Q --ignore Q001
ruff check . --isolated --select Q --ignore Q002
ruff check . --isolated --select Q --ignore Q000,Q001
ruff check . --isolated --select Q --ignore Q000,Q002
ruff check . --isolated --select Q --ignore Q001,Q002
```
...against:
```python
'''
bad docsting
'''
a = 'single'
b = '''
bad multi line
'''
```
## Summary
An annotated lambda assignment within a class scope is often
intentional. For example, within a dataclass or Pydantic model, these
are treated as fields rather than methods (and so can be passed values
in constructors).
I originally wrote this to special-case dataclasses and Pydantic
models... But was left feeling like we'd see more false positives here
for little gain (an annotated lambda within a `class` is likely
intentional?). Open to opinions, though.
Closes https://github.com/astral-sh/ruff/issues/10718.
