Implement F707 (DefaultExceptNotLast) (#101)

README.md

@@ -118,6 +118,7 @@ OPTIONS:
 | F634 | IfTuple | If test is a tuple, which is always `True` |
 | F704 | YieldOutsideFunction | a `yield` or `yield from` statement outside of a function/method |
 | F706 | ReturnOutsideFunction | a `return` statement outside of a function/method |
+| F707 | DefaultExceptNotLast | an `except:` block as not the last exception handler |
 | F821 | UndefinedName | Undefined name `...` |
 | F822 | UndefinedExport | Undefined name `...` in `__all__` |
 | F823 | UndefinedLocal | Local variable `...` referenced before assignment |

examples/generate_rules_table.rs

@@ -4,6 +4,7 @@ use ruff::checks::CheckKind;
 fn main() {
     let mut check_kinds: Vec<CheckKind> = vec![
         CheckKind::AssertTuple,
+        CheckKind::DefaultExceptNotLast,
         CheckKind::DuplicateArgumentName,
         CheckKind::FStringMissingPlaceholders,
         CheckKind::IfTuple,

resources/test/fixtures/F707.py

@@ -0,0 +1,46 @@
+try:
+    pass
+except:
+    pass
+except ValueError:
+    pass
+
+try:
+    pass
+except:
+    pass
+except ValueError:
+    pass
+finally:
+    pass
+
+try:
+    pass
+except:
+    pass
+except ValueError:
+    pass
+else:
+    pass
+
+try:
+    pass
+except:
+    pass
+
+try:
+    pass
+except ValueError:
+    pass
+except:
+    pass
+
+try:
+    pass
+except ValueError:
+    pass
+
+try:
+    pass
+finally:
+    pass

resources/test/fixtures/pyproject.toml

@@ -10,6 +10,7 @@ select = [
     "F634",
     "F704",
     "F706",
+    "F707",
     "F821",
     "F822",
     "F823",

src/check_ast.rs

@@ -295,6 +295,23 @@ impl Visitor for Checker<'_> {
                     }
                 }
             }
+            StmtKind::Try { handlers, .. } => {
+                if self
+                    .settings
+                    .select
+                    .contains(CheckKind::DefaultExceptNotLast.code())
+                {
+                    for (idx, handler) in handlers.iter().enumerate() {
+                        let ExcepthandlerKind::ExceptHandler { type_, .. } = &handler.node;
+                        if type_.is_none() && idx < handlers.len() - 1 {
+                            self.checks.push(Check {
+                                kind: CheckKind::DefaultExceptNotLast,
+                                location: handler.location,
+                            });
+                        }
+                    }
+                }
+            }
             _ => {}
         }
 

src/checks.rs

@@ -16,6 +16,7 @@ pub enum CheckCode {
     F634,
     F704,
     F706,
+    F707,
     F821,
     F822,
     F823,
@@ -38,6 +39,7 @@ impl FromStr for CheckCode {
             "F634" => Ok(CheckCode::F634),
             "F704" => Ok(CheckCode::F704),
             "F706" => Ok(CheckCode::F706),
+            "F707" => Ok(CheckCode::F707),
             "F821" => Ok(CheckCode::F821),
             "F822" => Ok(CheckCode::F822),
             "F823" => Ok(CheckCode::F823),
@@ -61,6 +63,7 @@ impl CheckCode {
             CheckCode::F634 => "F634",
             CheckCode::F704 => "F704",
             CheckCode::F706 => "F706",
+            CheckCode::F707 => "F707",
             CheckCode::F821 => "F821",
             CheckCode::F823 => "F823",
             CheckCode::F822 => "F822",
@@ -82,6 +85,7 @@ impl CheckCode {
             CheckCode::F634 => &LintSource::AST,
             CheckCode::F704 => &LintSource::AST,
             CheckCode::F706 => &LintSource::AST,
+            CheckCode::F707 => &LintSource::AST,
             CheckCode::F821 => &LintSource::AST,
             CheckCode::F822 => &LintSource::AST,
             CheckCode::F823 => &LintSource::AST,
@@ -109,6 +113,7 @@ pub enum CheckKind {
     LineTooLong,
     RaiseNotImplemented,
     ReturnOutsideFunction,
+    DefaultExceptNotLast,
     UndefinedLocal(String),
     UndefinedExport(String),
     UndefinedName(String),
@@ -130,6 +135,7 @@ impl CheckKind {
             CheckKind::LineTooLong => "LineTooLong",
             CheckKind::RaiseNotImplemented => "RaiseNotImplemented",
             CheckKind::ReturnOutsideFunction => "ReturnOutsideFunction",
+            CheckKind::DefaultExceptNotLast => "DefaultExceptNotLast",
             CheckKind::UndefinedLocal(_) => "UndefinedLocal",
             CheckKind::UndefinedExport(_) => "UndefinedExport",
             CheckKind::UndefinedName(_) => "UndefinedName",
@@ -151,6 +157,7 @@ impl CheckKind {
             CheckKind::LineTooLong => &CheckCode::E501,
             CheckKind::RaiseNotImplemented => &CheckCode::F901,
             CheckKind::ReturnOutsideFunction => &CheckCode::F706,
+            CheckKind::DefaultExceptNotLast => &CheckCode::F707,
             CheckKind::UndefinedExport(_) => &CheckCode::F822,
             CheckKind::UndefinedLocal(_) => &CheckCode::F823,
             CheckKind::UndefinedName(_) => &CheckCode::F821,
@@ -182,6 +189,9 @@ impl CheckKind {
             CheckKind::ReturnOutsideFunction => {
                 "a `return` statement outside of a function/method".to_string()
             }
+            CheckKind::DefaultExceptNotLast => {
+                "an `except:` block as not the last exception handler".to_string()
+            }
             CheckKind::UndefinedExport(name) => {
                 format!("Undefined name `{name}` in `__all__`")
             }

src/linter.rs

@@ -320,6 +320,47 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn f707() -> Result<()> {
+        let actual = check_path(
+            Path::new("./resources/test/fixtures/F707.py"),
+            &settings::Settings {
+                line_length: 88,
+                exclude: vec![],
+                select: BTreeSet::from([CheckCode::F707]),
+            },
+            &cache::Mode::None,
+        )?;
+        let expected = vec![
+            Message {
+                kind: CheckKind::DefaultExceptNotLast,
+                location: Location::new(3, 1),
+                filename: "./resources/test/fixtures/F707.py".to_string(),
+            },
+            Message {
+                kind: CheckKind::DefaultExceptNotLast,
+                location: Location::new(10, 1),
+                filename: "./resources/test/fixtures/F707.py".to_string(),
+            },
+            Message {
+                kind: CheckKind::DefaultExceptNotLast,
+                location: Location::new(19, 1),
+                filename: "./resources/test/fixtures/F707.py".to_string(),
+            },
+            Message {
+                kind: CheckKind::DefaultExceptNotLast,
+                location: Location::new(28, 1),
+                filename: "./resources/test/fixtures/F707.py".to_string(),
+            },
+        ];
+        assert_eq!(actual.len(), expected.len());
+        for i in 0..actual.len() {
+            assert_eq!(actual[i], expected[i]);
+        }
+
+        Ok(())
+    }
+
     #[test]
     fn f821() -> Result<()> {
         let actual = check_path(

src/pyproject.rs

@@ -245,6 +245,7 @@ other-attribute = 1
                     CheckCode::F634,
                     CheckCode::F704,
                     CheckCode::F706,
+                    CheckCode::F707,
                     CheckCode::F821,
                     CheckCode::F822,
                     CheckCode::F823,

src/settings.rs

@@ -51,6 +51,7 @@ impl Settings {
                     CheckCode::F631,
                     CheckCode::F634,
                     CheckCode::F706,
+                    CheckCode::F707,
                     CheckCode::F831,
                     CheckCode::F823,
                     CheckCode::F901,