Include BaseException in B017 rule (#5466)

Closes #5462.

crates/ruff/resources/test/fixtures/flake8_bugbear/B017.py

@@ -23,6 +23,10 @@ class Foobar(unittest.TestCase):
         with self.assertRaises(Exception):
             raise Exception("Evil I say!")
 
+    def also_evil_raises(self) -> None:
+        with self.assertRaises(BaseException):
+            raise Exception("Evil I say!")
+
     def context_manager_raises(self) -> None:
         with self.assertRaises(Exception) as ex:
             raise Exception("Context manager is good")
@@ -41,6 +45,9 @@ def test_pytest_raises():
     with pytest.raises(Exception):
         raise ValueError("Hello")
 
+    with pytest.raises(Exception), pytest.raises(ValueError):
+        raise ValueError("Hello")
+
     with pytest.raises(Exception, "hello"):
         raise ValueError("This is fine")
 

crates/ruff/src/checkers/ast/mod.rs

@@ -1409,7 +1409,7 @@ where
             Stmt::With(ast::StmtWith { items, body, .. })
             | Stmt::AsyncWith(ast::StmtAsyncWith { items, body, .. }) => {
                 if self.enabled(Rule::AssertRaisesException) {
-                    flake8_bugbear::rules::assert_raises_exception(self, stmt, items);
+                    flake8_bugbear::rules::assert_raises_exception(self, items);
                 }
                 if self.enabled(Rule::PytestRaisesWithMultipleStatements) {
                     flake8_pytest_style::rules::complex_raises(self, stmt, items, body);

crates/ruff/src/rules/flake8_bugbear/rules/assert_raises_exception.rs

@@ -1,22 +1,20 @@
-use rustpython_parser::ast::{self, Expr, Ranged, Stmt, WithItem};
+use std::fmt;
+
+use rustpython_parser::ast::{self, Expr, Ranged, WithItem};
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 
 use crate::checkers::ast::Checker;
 
-#[derive(Debug, PartialEq, Eq)]
-pub(crate) enum AssertionKind {
-    AssertRaises,
-    PytestRaises,
-}
-
 /// ## What it does
-/// Checks for `self.assertRaises(Exception)` or `pytest.raises(Exception)`.
+/// Checks for `assertRaises` and `pytest.raises` context managers that catch
+/// `Exception` or `BaseException`.
 ///
 /// ## Why is this bad?
 /// These forms catch every `Exception`, which can lead to tests passing even
-/// if, e.g., the code being tested is never executed due to a typo.
+/// if, e.g., the code under consideration raises a `SyntaxError` or
+/// `IndentationError`.
 ///
 /// Either assert for a more specific exception (builtin or custom), or use
 /// `assertRaisesRegex` or `pytest.raises(..., match=<REGEX>)` respectively.
@@ -32,30 +30,55 @@ pub(crate) enum AssertionKind {
 /// ```
 #[violation]
 pub struct AssertRaisesException {
-    kind: AssertionKind,
+    assertion: AssertionKind,
+    exception: ExceptionKind,
 }
 
 impl Violation for AssertRaisesException {
     #[derive_message_formats]
     fn message(&self) -> String {
-        match self.kind {
-            AssertionKind::AssertRaises => {
-                format!("`assertRaises(Exception)` should be considered evil")
+        let AssertRaisesException {
+            assertion,
+            exception,
+        } = self;
+        format!("`{assertion}({exception})` should be considered evil")
     }
-            AssertionKind::PytestRaises => {
-                format!("`pytest.raises(Exception)` should be considered evil")
 }
+
+#[derive(Debug, PartialEq, Eq)]
+enum AssertionKind {
+    AssertRaises,
+    PytestRaises,
+}
+
+impl fmt::Display for AssertionKind {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            AssertionKind::AssertRaises => fmt.write_str("assertRaises"),
+            AssertionKind::PytestRaises => fmt.write_str("pytest.raises"),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum ExceptionKind {
+    BaseException,
+    Exception,
+}
+
+impl fmt::Display for ExceptionKind {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            ExceptionKind::BaseException => fmt.write_str("BaseException"),
+            ExceptionKind::Exception => fmt.write_str("Exception"),
         }
     }
 }
 
 /// B017
-pub(crate) fn assert_raises_exception(checker: &mut Checker, stmt: &Stmt, items: &[WithItem]) {
-    let Some(item) = items.first() else {
-        return;
-    };
-    let item_context = &item.context_expr;
-    let Expr::Call(ast::ExprCall { func, args, keywords, range: _ }) = &item_context else {
+pub(crate) fn assert_raises_exception(checker: &mut Checker, items: &[WithItem]) {
+    for item in items {
+        let Expr::Call(ast::ExprCall { func, args, keywords, range: _ }) = &item.context_expr else {
             return;
         };
         if args.len() != 1 {
@@ -65,18 +88,18 @@ pub(crate) fn assert_raises_exception(checker: &mut Checker, stmt: &Stmt, items:
             return;
         }
 
-    if !checker
+        let Some(exception) = checker
             .semantic()
             .resolve_call_path(args.first().unwrap())
-        .map_or(false, |call_path| {
-            matches!(call_path.as_slice(), ["", "Exception"])
-        })
-    {
-        return;
+            .and_then(|call_path| {
+                match call_path.as_slice() {
+                    ["", "Exception"] => Some(ExceptionKind::Exception),
+                    ["", "BaseException"] => Some(ExceptionKind::BaseException),
+                    _ => None,
                 }
+            }) else { return; };
 
-    let kind = {
-        if matches!(func.as_ref(), Expr::Attribute(ast::ExprAttribute { attr, .. }) if attr == "assertRaises")
+        let assertion = if matches!(func.as_ref(), Expr::Attribute(ast::ExprAttribute { attr, .. }) if attr == "assertRaises")
         {
             AssertionKind::AssertRaises
         } else if checker
@@ -92,11 +115,14 @@ pub(crate) fn assert_raises_exception(checker: &mut Checker, stmt: &Stmt, items:
             AssertionKind::PytestRaises
         } else {
             return;
-        }
         };
 
         checker.diagnostics.push(Diagnostic::new(
-        AssertRaisesException { kind },
-        stmt.range(),
+            AssertRaisesException {
+                assertion,
+                exception,
+            },
+            item.range(),
         ));
     }
+}

crates/ruff/src/rules/flake8_bugbear/snapshots/ruff__rules__flake8_bugbear__tests__B017_B017.py.snap

@@ -1,27 +1,38 @@
 ---
 source: crates/ruff/src/rules/flake8_bugbear/mod.rs
 ---
-B017.py:23:9: B017 `assertRaises(Exception)` should be considered evil
+B017.py:23:14: B017 `assertRaises(Exception)` should be considered evil
    |
 21 | class Foobar(unittest.TestCase):
 22 |     def evil_raises(self) -> None:
 23 |         with self.assertRaises(Exception):
-   |  _________^
-24 | |             raise Exception("Evil I say!")
-   | |__________________________________________^ B017
-25 |   
-26 |       def context_manager_raises(self) -> None:
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+24 |             raise Exception("Evil I say!")
    |
 
-B017.py:41:5: B017 `pytest.raises(Exception)` should be considered evil
+B017.py:27:14: B017 `assertRaises(BaseException)` should be considered evil
    |
-40 |   def test_pytest_raises():
-41 |       with pytest.raises(Exception):
-   |  _____^
-42 | |         raise ValueError("Hello")
-   | |_________________________________^ B017
-43 |   
-44 |       with pytest.raises(Exception, "hello"):
+26 |     def also_evil_raises(self) -> None:
+27 |         with self.assertRaises(BaseException):
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+28 |             raise Exception("Evil I say!")
+   |
+
+B017.py:45:10: B017 `pytest.raises(Exception)` should be considered evil
+   |
+44 | def test_pytest_raises():
+45 |     with pytest.raises(Exception):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+46 |         raise ValueError("Hello")
+   |
+
+B017.py:48:10: B017 `pytest.raises(Exception)` should be considered evil
+   |
+46 |         raise ValueError("Hello")
+47 | 
+48 |     with pytest.raises(Exception), pytest.raises(ValueError):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+49 |         raise ValueError("Hello")
    |
 
 

crates/ruff/src/rules/pyflakes/rules/yield_outside_function.rs

@@ -9,7 +9,7 @@ use ruff_python_semantic::ScopeKind;
 use crate::checkers::ast::Checker;
 
 #[derive(Debug, PartialEq, Eq)]
-pub(crate) enum DeferralKeyword {
+enum DeferralKeyword {
     Yield,
     YieldFrom,
     Await,