Improves error message for [except*](https://peps.python.org/pep-0654/)
(Rules: B025, B029, B030, B904)
Example python snippet:
```python
try:
a = 1
except* ValueError:
a = 2
except* ValueError:
a = 2
try:
pass
except* ():
pass
try:
pass
except* 1: # error
pass
try:
raise ValueError
except* ValueError:
raise UserWarning
```
Error messages
Before:
```
$ ruff check --select=B foo.py
foo.py:6:9: B025 try-except block with duplicate exception `ValueError`
foo.py:11:1: B029 Using `except ():` with an empty tuple does not catch anything; add exceptions to handle
foo.py:16:9: B030 `except` handlers should only be exception classes or tuples of exception classes
foo.py:22:5: B904 Within an `except` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
Found 4 errors.
```
After:
```
$ ruff check --select=B foo.py
foo.py:6:9: B025 try-except* block with duplicate exception `ValueError`
foo.py:11:1: B029 Using `except* ():` with an empty tuple does not catch anything; add exceptions to handle
foo.py:16:9: B030 `except*` handlers should only be exception classes or tuples of exception classes
foo.py:22:5: B904 Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
Found 4 errors.
```
Closes https://github.com/astral-sh/ruff/issues/14791
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Fix#14525
## Test Plan
<!-- How was it tested? -->
New test cases
---------
Signed-off-by: harupy <hkawamura0130@gmail.com>
## Summary
Like https://github.com/astral-sh/ruff/pull/14063, but ensures that we
catch cases like `{1, True}` in which the items hash to the same value
despite not being identical.
## Summary
Pretty sure this should still be an error, but also, I think I added
this because of ecosystem CI? So want to see what pops up.
Closes https://github.com/astral-sh/ruff/issues/12164.
## 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 implements the rule B901, which is part of the opinionated rules
of `flake8-bugbear`.
This rule seems to be desired in `ruff` as per
https://github.com/astral-sh/ruff/issues/3758 and
https://github.com/astral-sh/ruff/issues/2954#issuecomment-1441162976.
## Test Plan
As this PR was made closely following the
[CONTRIBUTING.md](8a25531a71/CONTRIBUTING.md),
it tests using the snapshot approach, that is described there.
## Sources
The implementation is inspired by [the original implementation in the
`flake8-bugbear`
repository](d1aec4cbef/bugbear.py (L1092)).
The error message and [test
file](d1aec4cbef/tests/b901.py)
where also copied from there.
The documentation I came up with on my own and needs improvement. Maybe
the example given in
https://github.com/astral-sh/ruff/issues/2954#issuecomment-1441162976
could be used, but maybe they are too complex, I'm not sure.
## Open Questions
- [ ] Documentation. (See above.)
- [x] Can I access the parent in a visitor?
The [original
implementation](d1aec4cbef/bugbear.py (L1100))
references the `yield` statement's parent to check if it is an
expression statement. I didn't find a way to do this in `ruff` and used
the `is_expresssion_statement` field on the visitor instead. What are
your thoughts on this? Is it possible and / or desired to access the
parent node here?
- [x] Is `Option::is_some(...)` -> `...unwrap()` the right thing to do?
Referring to [this piece of
code](9d5a280f71/crates/ruff_linter/src/rules/flake8_bugbear/rules/return_x_in_generator.rs (L91-L96)).
From my understanding, the `.unwrap()` is safe, because it is checked
that `return_` is not `None`. However, I feel like I missed a more
elegant solution that does both in one.
## Other
I don't know a lot about this rule, I just implemented it because I
found it in a
https://github.com/astral-sh/ruff/labels/good%20first%20issue.
I'm new to Rust, so any constructive critisism is appreciated.
---------
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
## Summary
While I was here, I also updated the rule to use
`function_type::classify` rather than hard-coding `staticmethod` and
friends.
Per Carl:
> Enum instances are already referred to by the class, forming a cycle
that won't get collected until the class itself does. At which point the
`lru_cache` itself would be collected, too.
Closes https://github.com/astral-sh/ruff/issues/9912.
## Summary
I think the check included here does make sense, but I don't see why we
would allow it if a value is provided for the attribute -- since, in
that case, isn't it _not_ abstract?
Closes: https://github.com/astral-sh/ruff/issues/11208.
## 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 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
Closes#10337.
I've fixed the code to count usage of variable.
Usage count inside the block is reset when there is a following
statement.
- continue
- break
- return
## Test Plan
Add test case.
Fixes#10426
## Summary
Fix rule B030 giving a false positive with Tuple operations like `+`.
[Playground](https://play.ruff.rs/17b086bc-cc43-40a7-b5bf-76d7d5fce78a)
```python
try:
...
except (ValueError,TypeError) + (EOFError,ArithmeticError):
...
```
## Reviewer notes
This is a little more convoluted than I was expecting -- because we can
have valid nested Tuples with operations done on them, the flattening
logic has become a bit more complex.
Shall I guard this behind --preview?
## Test Plan
Unit tested.
## 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
This PR updates `B015` and `B018` to ignore last top-level expressions
in each cell of a Jupyter Notebook.
Part of #8669
## Test Plan
Add test cases for both rules and update the snapshots.
## Summary
Fixes#7616 by ensuring that
[B006](https://docs.astral.sh/ruff/rules/mutable-argument-default/#mutable-argument-default-b006)
fixes are inserted after module imports.
I have created a new test file, `B006_5.py`. This is mainly because I
have been working on this on and off, and the merge conflicts were
easier to handle in a separate file. If needed, I can move it into
another file.
## Test Plan
`cargo test`
