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Improve error messages for except* (B025, B029, B030, B904) #14791 (#14815)

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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>
This commit is contained in:
ABDULRAHMAN ALRAHMA
2024-12-08 17:37:34 +00:00
committed by GitHub
parent 269e47be96
commit 85402097fc
12 changed files with 312 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B025.py vendored
View File

@@ -1,6 +1,6 @@
"""
Should emit:
B025 - on lines 15, 22, 31
B025 - on lines 15, 22, 31, 40, 47, 56
"""
import pickle
@@ -36,3 +36,28 @@ except ValueError:
a = 2
except (OSError, TypeError):
a = 2
try:
a = 1
except* ValueError:
a = 2
except* ValueError:
a = 2
try:
a = 1
except* pickle.PickleError:
a = 2
except* ValueError:
a = 2
except* pickle.PickleError:
a = 2
try:
a = 1
except* (ValueError, TypeError):
a = 2
except* ValueError:
a = 2
except* (OSError, TypeError):
a = 2

14
crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B029.py vendored
View File

@@ -1,6 +1,6 @@
"""
Should emit:
B029 - on lines 8 and 13
B029 - on lines 8, 13, 18 and 23
"""
try:
@@ -11,4 +11,14 @@ except ():
try:
pass
except () as e:
pass
pass
try:
pass
except* ():
pass
try:
pass
except* () as e:
pass

20
crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B030.py vendored
View File

@@ -130,3 +130,23 @@ try:
pass
except (a, b) * (c, d): # B030
pass
try:
pass
except* 1: # Error
pass
try:
pass
except* (1, ValueError): # Error
pass
try:
pass
except* (ValueError, (RuntimeError, (KeyError, TypeError))): # Error
pass
try:
pass
except* (a, b) * (c, d): # B030
pass

28
crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B904.py vendored
View File

@@ -1,6 +1,6 @@
"""
Should emit:
B904 - on lines 10, 11, 16, 62, and 64
B904 - on lines 10, 11, 16, 62, 64, 79, 81, 87, 88, 93 and 97
"""
try:
@@ -71,3 +71,29 @@ except Exception as e:
match 0:
case 0:
raise RuntimeError("boom!")
try:
...
except* Exception as e:
if ...:
raise RuntimeError("boom!")
else:
raise RuntimeError("bang!")
try:
raise ValueError
except* ValueError:
if "abc":
raise TypeError
raise UserWarning
except* AssertionError:
raise # Bare `raise` should not be an error
except* Exception as err:
assert err
raise Exception("No cause here...")
except* BaseException as err:
raise err
except* BaseException as err:
raise some_other_err
finally:
raise Exception("Nothing to chain from, so no warning here")

15
crates/ruff_linter/src/rules/flake8_bugbear/rules/duplicate_exceptions.rs
View File

@@ -42,13 +42,18 @@ use crate::registry::Rule;
#[derive(ViolationMetadata)]
pub(crate) struct DuplicateTryBlockException {
name: String,
is_star: bool,
}
impl Violation for DuplicateTryBlockException {
#[derive_message_formats]
fn message(&self) -> String {
let DuplicateTryBlockException { name } = self;
format!("try-except block with duplicate exception `{name}`")
let DuplicateTryBlockException { name, is_star } = self;
if *is_star {
format!("try-except* block with duplicate exception `{name}`")
} else {
format!("try-except block with duplicate exception `{name}`")
}
}
}
@@ -207,9 +212,15 @@ pub(crate) fn duplicate_exceptions(checker: &mut Checker, handlers: &[ExceptHand
if checker.enabled(Rule::DuplicateTryBlockException) {
for (name, exprs) in duplicates {
for expr in exprs {
let is_star = checker
.semantic()
.current_statement()
.as_try_stmt()
.is_some_and(|try_stmt| try_stmt.is_star);
checker.diagnostics.push(Diagnostic::new(
DuplicateTryBlockException {
name: name.segments().join("."),
is_star,
},
expr.range(),
));

19
crates/ruff_linter/src/rules/flake8_bugbear/rules/except_with_empty_tuple.rs
View File

@@ -34,13 +34,18 @@ use crate::checkers::ast::Checker;
/// ## References
/// - [Python documentation: `except` clause](https://docs.python.org/3/reference/compound_stmts.html#except-clause)
#[derive(ViolationMetadata)]
pub(crate) struct ExceptWithEmptyTuple;
pub(crate) struct ExceptWithEmptyTuple {
is_star: bool,
}
impl Violation for ExceptWithEmptyTuple {
#[derive_message_formats]
fn message(&self) -> String {
"Using `except ():` with an empty tuple does not catch anything; add exceptions to handle"
.to_string()
if self.is_star {
"Using `except* ():` with an empty tuple does not catch anything; add exceptions to handle".to_string()
} else {
"Using `except ():` with an empty tuple does not catch anything; add exceptions to handle".to_string()
}
}
}
@@ -54,9 +59,15 @@ pub(crate) fn except_with_empty_tuple(checker: &mut Checker, except_handler: &Ex
let Expr::Tuple(ast::ExprTuple { elts, .. }) = type_.as_ref() else {
return;
};
if elts.is_empty() {
let is_star = checker
.semantic()
.current_statement()
.as_try_stmt()
.is_some_and(|try_stmt| try_stmt.is_star);
checker.diagnostics.push(Diagnostic::new(
ExceptWithEmptyTuple,
ExceptWithEmptyTuple { is_star },
except_handler.range(),
));
}

25
crates/ruff_linter/src/rules/flake8_bugbear/rules/except_with_non_exception_classes.rs
View File

@@ -35,13 +35,20 @@ use crate::checkers::ast::Checker;
/// - [Python documentation: `except` clause](https://docs.python.org/3/reference/compound_stmts.html#except-clause)
/// - [Python documentation: Built-in Exceptions](https://docs.python.org/3/library/exceptions.html#built-in-exceptions)
#[derive(ViolationMetadata)]
pub(crate) struct ExceptWithNonExceptionClasses;
pub(crate) struct ExceptWithNonExceptionClasses {
is_star: bool,
}
impl Violation for ExceptWithNonExceptionClasses {
#[derive_message_formats]
fn message(&self) -> String {
"`except` handlers should only be exception classes or tuples of exception classes"
.to_string()
if self.is_star {
"`except*` handlers should only be exception classes or tuples of exception classes"
.to_string()
} else {
"`except` handlers should only be exception classes or tuples of exception classes"
.to_string()
}
}
}
@@ -60,9 +67,15 @@ pub(crate) fn except_with_non_exception_classes(
expr,
Expr::Subscript(_) | Expr::Attribute(_) | Expr::Name(_) | Expr::Call(_),
) {
checker
.diagnostics
.push(Diagnostic::new(ExceptWithNonExceptionClasses, expr.range()));
let is_star = checker
.semantic()
.current_statement()
.as_try_stmt()
.is_some_and(|try_stmt| try_stmt.is_star);
checker.diagnostics.push(Diagnostic::new(
ExceptWithNonExceptionClasses { is_star },
expr.range(),
));
}
}
}

29
crates/ruff_linter/src/rules/flake8_bugbear/rules/raise_without_from_inside_except.rs
View File

@@ -47,14 +47,22 @@ use crate::checkers::ast::Checker;
/// ## References
/// - [Python documentation: `raise` statement](https://docs.python.org/3/reference/simple_stmts.html#the-raise-statement)
#[derive(ViolationMetadata)]
pub(crate) struct RaiseWithoutFromInsideExcept;
pub(crate) struct RaiseWithoutFromInsideExcept {
is_star: bool,
}
impl Violation for RaiseWithoutFromInsideExcept {
#[derive_message_formats]
fn message(&self) -> String {
"Within an `except` clause, raise exceptions with `raise ... from err` or `raise ... \
from None` to distinguish them from errors in exception handling"
.to_string()
if self.is_star {
"Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... \
from None` to distinguish them from errors in exception handling"
.to_string()
} else {
"Within an `except` clause, raise exceptions with `raise ... from err` or `raise ... \
from None` to distinguish them from errors in exception handling"
.to_string()
}
}
}
@@ -92,9 +100,16 @@ pub(crate) fn raise_without_from_inside_except(
}
}
checker
.diagnostics
.push(Diagnostic::new(RaiseWithoutFromInsideExcept, range));
let is_star = checker
.semantic()
.current_statement()
.as_try_stmt()
.is_some_and(|try_stmt| try_stmt.is_star);
checker.diagnostics.push(Diagnostic::new(
RaiseWithoutFromInsideExcept { is_star },
range,
));
}
}
}

37
crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B025_B025.py.snap
View File

@@ -38,3 +38,40 @@ B025.py:37:18: B025 try-except block with duplicate exception `TypeError`
| ^^^^^^^^^ B025
38 | a = 2
|
B025.py:44:9: B025 try-except* block with duplicate exception `ValueError`
|
42 | except* ValueError:
43 | a = 2
44 | except* ValueError:
| ^^^^^^^^^^ B025
45 | a = 2
|
B025.py:53:9: B025 try-except* block with duplicate exception `pickle.PickleError`
|
51 | except* ValueError:
52 | a = 2
53 | except* pickle.PickleError:
| ^^^^^^^^^^^^^^^^^^ B025
54 | a = 2
|
B025.py:60:9: B025 try-except* block with duplicate exception `ValueError`
|
58 | except* (ValueError, TypeError):
59 | a = 2
60 | except* ValueError:
| ^^^^^^^^^^ B025
61 | a = 2
62 | except* (OSError, TypeError):
|
B025.py:62:19: B025 try-except* block with duplicate exception `TypeError`
|
60 | except* ValueError:
61 | a = 2
62 | except* (OSError, TypeError):
| ^^^^^^^^^ B025
63 | a = 2
|

22
crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B029_B029.py.snap
View File

@@ -20,4 +20,26 @@ B029.py:13:1: B029 Using `except ():` with an empty tuple does not catch anythin
13 | / except () as e:
14 | | pass
| |________^ B029
15 |
16 | try:
|
B029.py:18:1: B029 Using `except* ():` with an empty tuple does not catch anything; add exceptions to handle
|
16 | try:
17 | pass
18 | / except* ():
19 | | pass
| |________^ B029
20 |
21 | try:
|
B029.py:23:1: B029 Using `except* ():` with an empty tuple does not catch anything; add exceptions to handle
|
21 | try:
22 | pass
23 | / except* () as e:
24 | | pass
| |________^ B029
|

38
crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B030_B030.py.snap
View File

@@ -47,7 +47,7 @@ B030.py:33:29: B030 `except` handlers should only be exception classes or tuples
34 | pass
|
B030.py:39:28: B030 `except` handlers should only be exception classes or tuples of exception classes
B030.py:39:28: B030 `except*` handlers should only be exception classes or tuples of exception classes
|
37 | try:
38 | pass
@@ -64,3 +64,39 @@ B030.py:131:8: B030 `except` handlers should only be exception classes or tuples
| ^^^^^^^^^^^^^^^ B030
132 | pass
|
B030.py:136:9: B030 `except*` handlers should only be exception classes or tuples of exception classes
|
134 | try:
135 | pass
136 | except* 1: # Error
| ^ B030
137 | pass
|
B030.py:141:10: B030 `except*` handlers should only be exception classes or tuples of exception classes
|
139 | try:
140 | pass
141 | except* (1, ValueError): # Error
| ^ B030
142 | pass
|
B030.py:146:22: B030 `except*` handlers should only be exception classes or tuples of exception classes
|
144 | try:
145 | pass
146 | except* (ValueError, (RuntimeError, (KeyError, TypeError))): # Error
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B030
147 | pass
|
B030.py:151:9: B030 `except*` handlers should only be exception classes or tuples of exception classes
|
149 | try:
150 | pass
151 | except* (a, b) * (c, d): # B030
| ^^^^^^^^^^^^^^^ B030
152 | pass
|

62
crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B904_B904.py.snap
View File

@@ -66,4 +66,66 @@ B904.py:73:13: B904 Within an `except` clause, raise exceptions with `raise ...
72 | case 0:
73 | raise RuntimeError("boom!")
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ B904
74 |
75 | try:
|
B904.py:79:9: B904 Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
|
77 | except* Exception as e:
78 | if ...:
79 | raise RuntimeError("boom!")
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ B904
80 | else:
81 | raise RuntimeError("bang!")
|
B904.py:81:9: B904 Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
|
79 | raise RuntimeError("boom!")
80 | else:
81 | raise RuntimeError("bang!")
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ B904
82 |
83 | try:
|
B904.py:87:9: B904 Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
|
85 | except* ValueError:
86 | if "abc":
87 | raise TypeError
| ^^^^^^^^^^^^^^^ B904
88 | raise UserWarning
89 | except* AssertionError:
|
B904.py:88:5: B904 Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
|
86 | if "abc":
87 | raise TypeError
88 | raise UserWarning
| ^^^^^^^^^^^^^^^^^ B904
89 | except* AssertionError:
90 | raise # Bare `raise` should not be an error
|
B904.py:93:5: B904 Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
|
91 | except* Exception as err:
92 | assert err
93 | raise Exception("No cause here...")
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B904
94 | except* BaseException as err:
95 | raise err
|
B904.py:97:5: B904 Within an `except*` clause, raise exceptions with `raise ... from err` or `raise ... from None` to distinguish them from errors in exception handling
|
95 | raise err
96 | except* BaseException as err:
97 | raise some_other_err
| ^^^^^^^^^^^^^^^^^^^^ B904
98 | finally:
99 | raise Exception("Nothing to chain from, so no warning here")
|