## Summary
Fixes#20973 (`docstring-extraneous-exception`) false positive when
exceptions mentioned in docstrings are caught and explicitly re-raised
using `raise e` or `raise e from None`.
## Problem Analysis
The DOC502 rule was incorrectly flagging exceptions mentioned in
docstrings as "not explicitly raised" when they were actually being
explicitly re-raised through exception variables bound in `except`
clauses.
**Root Cause**: The `BodyVisitor` in `check_docstring.rs` only checked
for direct exception references (like `raise OSError()`) but didn't
recognize when a variable bound to an exception in an `except` clause
was being re-raised.
**Example of the bug**:
```python
def f():
"""Do nothing.
Raises
------
OSError
If the OS errors.
"""
try:
pass
except OSError as e:
raise e # This was incorrectly flagged as not explicitly raising OSError
```
The issue occurred because `resolve_qualified_name(e)` couldn't resolve
the variable `e` to a qualified exception name, since `e` is just a
variable binding, not a direct reference to an exception class.
## Approach
Modified the `BodyVisitor` in
`crates/ruff_linter/src/rules/pydoclint/rules/check_docstring.rs` to:
1. **Track exception variable bindings**: Added `exception_variables`
field to map exception variable names to their exception types within
`except` clauses
2. **Enhanced raise statement detection**: Updated `visit_stmt` to check
if a `raise` statement uses a variable name that's bound to an exception
in the current `except` clause
3. **Proper scope management**: Clear exception variable mappings when
leaving `except` handlers to prevent cross-contamination
**Key changes**:
- Added `exception_variables: FxHashMap<&'a str, QualifiedName<'a>>` to
track variable-to-exception mappings
- Enhanced `visit_except_handler` to store exception variable bindings
when entering `except` clauses
- Modified `visit_stmt` to check for variable-based re-raising: `raise
e` → lookup `e` in `exception_variables`
- Clear mappings when exiting `except` handlers to maintain proper scope
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
## Summary
Fixes#12630.
DOC501 and DOC502 now understand functions with constructs like this to
be explicitly raising `TypeError` (which should be documented in a
function's docstring):
```py
try:
foo():
except TypeError:
...
raise
```
I made an exception for `Exception` and `BaseException`, however.
Constructs like this are reasonably common, and I don't think anybody
would say that it's worth putting in the docstring that it raises "some
kind of generic exception":
```py
try:
foo()
except BaseException:
do_some_logging()
raise
```
## Test Plan
`cargo test -p ruff_linter --lib`
## Summary
These are the first rules implemented as part of #458, but I plan to
implement more.
Specifically, this implements `docstring-missing-exception` which checks
for raised exceptions not documented in the docstring, and
`docstring-extraneous-exception` which checks for exceptions in the
docstring not present in the body.
## Test Plan
Test fixtures added for both google and numpy style.
Dan Parizher
Alex Waygood
Auguste Lalande