RUF023: Don't sort __match_args__, only __slots__ (#9724)

Fixes #9723. I'm pretty embarrassed I forgot that order was important
here :(

crates/ruff_linter/resources/test/fixtures/ruff/RUF023.py

@@ -4,22 +4,22 @@
 
 class Klass:
     __slots__ = ["d", "c", "b", "a"]  # a comment that is untouched
-    __match_args__ = ("d", "c", "b", "a")
+    __slots__ = ("d", "c", "b", "a")
 
     # Quoting style is retained,
     # but unnecessary parens are not
     __slots__: set = {'b', "c", ((('a')))}
     # Trailing commas are also not retained for single-line definitions
     # (but they are in multiline definitions)
-    __match_args__: tuple = ("b", "c", "a",)
+    __slots__: tuple = ("b", "c", "a",)
 
 class Klass2:
     if bool():
         __slots__ = {"x": "docs for x", "m": "docs for m", "a": "docs for a"}
     else:
         __slots__ = "foo3", "foo2", "foo1"  # NB: an implicit tuple (without parens)
 
-    __match_args__: list[str] = ["the", "three", "little", "pigs"]
+    __slots__: list[str] = ["the", "three", "little", "pigs"]
     __slots__ = ("parenthesized_item"), "in", ("an_unparenthesized_tuple")
     # we use natural sort,
     # not alphabetical sort or "isort-style" sort
@@ -37,7 +37,7 @@ class Klass3:
         # a comment regarding 'a0':
         "a0"
     )
-    __match_args__ = [
+    __slots__ = [
         "d",
         "c",  # a comment regarding 'c'
         "b",
@@ -61,7 +61,7 @@ class Klass4:
     )  # comment6
     # comment7
 
-    __match_args__ = [  # comment0
+    __slots__ = [  # comment0
         # comment1
         # comment2
         "dx", "cx", "bx", "ax"  # comment3
@@ -139,7 +139,7 @@ class SlotUser:
                  'distance': 'measured in kilometers'}
 
 class Klass5:
-    __match_args__ = (
+    __slots__ = (
         "look",
         (
             "a_veeeeeeeeeeeeeeeeeeery_long_parenthesized_item"
@@ -194,14 +194,14 @@ class BezierBuilder4:
 
 class Klass6:
     __slots__ = ()
-    __match_args__ = []
+    __slots__ = []
     __slots__ = ("single_item",)
-    __match_args__ = (
+    __slots__ = (
         "single_item_multiline",
     )
     __slots__ = {"single_item",}
     __slots__ = {"single_item_no_trailing_comma": "docs for that"}
-    __match_args__ = [
+    __slots__ = [
         "single_item_multiline_no_trailing_comma"
     ]
     __slots__ = ("not_a_tuple_just_a_string")
@@ -218,11 +218,11 @@ class Klass6:
 
 __slots__ = ("b", "a", "e", "d")
 __slots__ = ["b", "a", "e", "d"]
-__match_args__ = ["foo", "bar", "antipasti"]
+__slots__ = ["foo", "bar", "antipasti"]
 
 class Klass6:
     __slots__ = (9, 8, 7)
-    __match_args__ = (  # This is just an empty tuple,
+    __slots__ = (  # This is just an empty tuple,
         # but,
         # it's very well
     )  # documented
@@ -245,10 +245,10 @@ class Klass6:
     __slots__ = [
         ()
     ]
-    __match_args__ = (
+    __slots__ = (
         ()
     )
-    __match_args__ = (
+    __slots__ = (
         []
     )
     __slots__ = (
@@ -257,12 +257,9 @@ class Klass6:
     __slots__ = (
         [],
     )
-    __match_args__ = (
+    __slots__ = (
         "foo", [], "bar"
     )
-    __match_args__ = [
+    __slots__ = [
         "foo", (), "bar"
     ]
-
-    __match_args__ = {"a", "set", "for", "__match_args__", "is invalid"}
-    __match_args__ = {"this": "is", "also": "invalid"}

crates/ruff_linter/src/rules/ruff/rules/sequence_sorting.rs

@@ -2,7 +2,7 @@
 ///
 /// Examples where these are useful:
 /// - Sorting `__all__` in the global scope,
-/// - Sorting `__slots__` or `__match_args__` in a class scope
+/// - Sorting `__slots__` in a class scope
 use std::borrow::Cow;
 use std::cmp::Ordering;
 

crates/ruff_linter/src/rules/ruff/rules/sort_dunder_slots.rs

@@ -1,5 +1,4 @@
 use std::borrow::Cow;
-use std::fmt::Display;
 
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
@@ -17,14 +16,12 @@ use crate::rules::ruff::rules::sequence_sorting::{
 use itertools::izip;
 
 /// ## What it does
-/// Checks for `__slots__` and `__match_args__`
-/// definitions that are not ordered according to a
+/// Checks for `__slots__` definitions that are not ordered according to a
 /// [natural sort](https://en.wikipedia.org/wiki/Natural_sort_order).
 ///
 /// ## Why is this bad?
-/// Consistency is good. Use a common convention for
-/// these special variables to make your code more
-/// readable and idiomatic.
+/// Consistency is good. Use a common convention for this special variable
+/// to make your code more readable and idiomatic.
 ///
 /// ## Example
 /// ```python
@@ -40,51 +37,25 @@ use itertools::izip;
 #[violation]
 pub struct UnsortedDunderSlots {
     class_name: String,
-    class_variable: SpecialClassDunder,
 }
 
 impl Violation for UnsortedDunderSlots {
     const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
 
     #[derive_message_formats]
     fn message(&self) -> String {
-        let UnsortedDunderSlots {
-            class_name,
-            class_variable,
-        } = self;
-        format!("`{class_name}.{class_variable}` is not sorted")
+        format!("`{}.__slots__` is not sorted", self.class_name)
     }
 
     fn fix_title(&self) -> Option<String> {
-        let UnsortedDunderSlots {
-            class_name,
-            class_variable,
-        } = self;
         Some(format!(
-            "Apply a natural sort to `{class_name}.{class_variable}`"
+            "Apply a natural sort to `{}.__slots__`",
+            self.class_name
         ))
     }
 }
 
-/// Enumeration of the two special class dunders
-/// that we're interested in for this rule: `__match_args__` and `__slots__`
-#[derive(Debug, Eq, PartialEq, Copy, Clone)]
-enum SpecialClassDunder {
-    Slots,
-    MatchArgs,
-}
-
-impl Display for SpecialClassDunder {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let string = match self {
-            Self::MatchArgs => "__match_args__",
-            Self::Slots => "__slots__",
-        };
-        write!(f, "{string}")
-    }
-}
-
-/// Sort a `__slots__`/`__match_args__` definition
+/// Sort a `__slots__` definition
 /// represented by a `StmtAssign` AST node.
 /// For example: `__slots__ = ["b", "c", "a"]`.
 pub(crate) fn sort_dunder_slots_assign(
@@ -96,7 +67,7 @@ pub(crate) fn sort_dunder_slots_assign(
     }
 }
 
-/// Sort a `__slots__`/`__match_args__` definition
+/// Sort a `__slots__` definition
 /// represented by a `StmtAnnAssign` AST node.
 /// For example: `__slots__: list[str] = ["b", "c", "a"]`.
 pub(crate) fn sort_dunder_slots_ann_assign(checker: &mut Checker, node: &ast::StmtAnnAssign) {
@@ -107,8 +78,7 @@ pub(crate) fn sort_dunder_slots_ann_assign(checker: &mut Checker, node: &ast::St
 
 const SORTING_STYLE: SortingStyle = SortingStyle::Natural;
 
-/// Sort a tuple, list, dict or set that defines `__slots__`
-/// or `__match_args__` in a class scope.
+/// Sort a tuple, list, dict or set that defines `__slots__` in a class scope.
 ///
 /// This routine checks whether the display is sorted, and emits a
 /// violation if it is not sorted. If the tuple/list/set was not sorted,
@@ -118,21 +88,19 @@ fn sort_dunder_slots(checker: &mut Checker, target: &ast::Expr, node: &ast::Expr
         return;
     };
 
-    let dunder_kind = match id.as_str() {
-        "__slots__" => SpecialClassDunder::Slots,
-        "__match_args__" => SpecialClassDunder::MatchArgs,
-        _ => return,
-    };
+    if id != "__slots__" {
+        return;
+    }
 
-    // We're only interested in `__slots__`/`__match_args__` in the class scope
+    // We're only interested in `__slots__` in the class scope
     let ScopeKind::Class(ast::StmtClassDef {
         name: class_name, ..
     }) = checker.semantic().current_scope().kind
     else {
         return;
     };
 
-    let Some(display) = StringLiteralDisplay::new(node, dunder_kind) else {
+    let Some(display) = StringLiteralDisplay::new(node) else {
         return;
     };
 
@@ -144,7 +112,6 @@ fn sort_dunder_slots(checker: &mut Checker, target: &ast::Expr, node: &ast::Expr
     let mut diagnostic = Diagnostic::new(
         UnsortedDunderSlots {
             class_name: class_name.to_string(),
-            class_variable: dunder_kind,
         },
         display.range,
     );
@@ -179,47 +146,42 @@ impl Ranged for StringLiteralDisplay<'_> {
 }
 
 impl<'a> StringLiteralDisplay<'a> {
-    fn new(node: &'a ast::Expr, dunder_kind: SpecialClassDunder) -> Option<Self> {
-        let result = match (dunder_kind, node) {
-            (_, ast::Expr::List(ast::ExprList { elts, range, .. })) => {
+    fn new(node: &'a ast::Expr) -> Option<Self> {
+        let result = match node {
+            ast::Expr::List(ast::ExprList { elts, range, .. }) => {
                 let display_kind = DisplayKind::Sequence(SequenceKind::List);
                 Self {
                     elts: Cow::Borrowed(elts),
                     range: *range,
                     display_kind,
                 }
             }
-            (_, ast::Expr::Tuple(tuple_node @ ast::ExprTuple { elts, range, .. })) => {
+            ast::Expr::Tuple(tuple_node @ ast::ExprTuple { elts, range, .. }) => {
                 let display_kind = DisplayKind::Sequence(SequenceKind::Tuple(tuple_node));
                 Self {
                     elts: Cow::Borrowed(elts),
                     range: *range,
                     display_kind,
                 }
             }
-            (SpecialClassDunder::Slots, ast::Expr::Set(ast::ExprSet { elts, range })) => {
+            ast::Expr::Set(ast::ExprSet { elts, range }) => {
                 let display_kind = DisplayKind::Sequence(SequenceKind::Set);
                 Self {
                     elts: Cow::Borrowed(elts),
                     range: *range,
                     display_kind,
                 }
             }
-            (
-                SpecialClassDunder::Slots,
-                ast::Expr::Dict(ast::ExprDict {
-                    keys,
-                    values,
-                    range,
-                }),
-            ) => {
+            ast::Expr::Dict(ast::ExprDict {
+                keys,
+                values,
+                range,
+            }) => {
                 let mut narrowed_keys = Vec::with_capacity(values.len());
                 for key in keys {
                     if let Some(key) = key {
                         // This is somewhat unfortunate,
-                        // *but* only `__slots__` can be a dict out of
-                        // `__all__`, `__slots__` and `__match_args__`,
-                        // and even for `__slots__`, using a dict is very rare
+                        // *but* using a dict for __slots__ is very rare
                         narrowed_keys.push(key.to_owned());
                     } else {
                         return None;