[flake8-pyi] Add PYI032 rule with autofix (#4695)

crates/ruff/resources/test/fixtures/flake8_pyi/PYI032.py

@@ -0,0 +1,24 @@
+from typing import Any
+import typing
+
+
+class Bad:
+    def __eq__(self, other: Any) -> bool: ...  # Fine because not a stub file
+    def __ne__(self, other: typing.Any) -> typing.Any: ...  # Fine because not a stub file
+
+
+class Good:
+  def __eq__(self, other: object) -> bool: ...
+
+  def __ne__(self, obj: object) -> int: ...
+
+
+class WeirdButFine:
+    def __eq__(self, other: Any, strange_extra_arg: list[str]) -> Any: ...
+    def __ne__(self, *, kw_only_other: Any) -> bool: ...
+
+
+class Unannotated:
+  def __eq__(self) -> Any: ...
+  def __ne__(self) -> bool: ...
+

crates/ruff/resources/test/fixtures/flake8_pyi/PYI032.pyi

@@ -0,0 +1,24 @@
+from typing import Any
+import typing
+
+
+class Bad:
+    def __eq__(self, other: Any) -> bool: ...  # Y032
+    def __ne__(self, other: typing.Any) -> typing.Any: ...  # Y032
+
+
+class Good:
+  def __eq__(self, other: object) -> bool: ...
+
+  def __ne__(self, obj: object) -> int: ...
+
+
+class WeirdButFine:
+    def __eq__(self, other: Any, strange_extra_arg: list[str]) -> Any: ...
+    def __ne__(self, *, kw_only_other: Any) -> bool: ...
+
+
+class Unannotated:
+  def __eq__(self) -> Any: ...
+  def __ne__(self) -> bool: ...
+

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

@@ -429,6 +429,9 @@ where
                     if self.enabled(Rule::StubBodyMultipleStatements) {
                         flake8_pyi::rules::stub_body_multiple_statements(self, stmt, body);
                     }
+                    if self.enabled(Rule::AnyEqNeAnnotation) {
+                        flake8_pyi::rules::any_eq_ne_annotation(self, name, args);
+                    }
                 }
 
                 if self.enabled(Rule::DunderFunctionName) {

crates/ruff/src/codes.rs

@@ -590,6 +590,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8Pyi, "016") => (RuleGroup::Unspecified, Rule::DuplicateUnionMember),
         (Flake8Pyi, "020") => (RuleGroup::Unspecified, Rule::QuotedAnnotationInStub),
         (Flake8Pyi, "021") => (RuleGroup::Unspecified, Rule::DocstringInStub),
+        (Flake8Pyi, "032") => (RuleGroup::Unspecified, Rule::AnyEqNeAnnotation),
         (Flake8Pyi, "033") => (RuleGroup::Unspecified, Rule::TypeCommentInStub),
         (Flake8Pyi, "042") => (RuleGroup::Unspecified, Rule::SnakeCaseTypeAlias),
         (Flake8Pyi, "043") => (RuleGroup::Unspecified, Rule::TSuffixedTypeAlias),

crates/ruff/src/registry.rs

@@ -509,6 +509,7 @@ ruff_macros::register_rules!(
     rules::flake8_errmsg::rules::FStringInException,
     rules::flake8_errmsg::rules::DotFormatInException,
     // flake8-pyi
+    rules::flake8_pyi::rules::AnyEqNeAnnotation,
     rules::flake8_pyi::rules::ArgumentDefaultInStub,
     rules::flake8_pyi::rules::AssignmentDefaultInStub,
     rules::flake8_pyi::rules::BadVersionInfoComparison,

crates/ruff/src/rules/flake8_pyi/mod.rs

@@ -12,6 +12,8 @@ mod tests {
     use crate::test::test_path;
     use crate::{assert_messages, settings};
 
+    #[test_case(Rule::AnyEqNeAnnotation, Path::new("PYI032.py"))]
+    #[test_case(Rule::AnyEqNeAnnotation, Path::new("PYI032.pyi"))]
     #[test_case(Rule::ArgumentDefaultInStub, Path::new("PYI014.py"))]
     #[test_case(Rule::ArgumentDefaultInStub, Path::new("PYI014.pyi"))]
     #[test_case(Rule::AssignmentDefaultInStub, Path::new("PYI015.py"))]

crates/ruff/src/rules/flake8_pyi/rules/any_eq_ne_annotation.rs

@@ -0,0 +1,94 @@
+use rustpython_parser::ast::{Arguments, Ranged};
+
+use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Edit, Fix};
+use ruff_macros::{derive_message_formats, violation};
+
+use crate::checkers::ast::Checker;
+use crate::registry::AsRule;
+
+/// ## What it does
+/// Checks for `__eq__` and `__ne__` implementations that use `typing.Any` as
+/// the type annotation for the `obj` parameter.
+///
+/// ## Why is this bad?
+/// The Python documentation recommends the use of `object` to "indicate that a
+/// value could be any type in a typesafe manner", while `Any` should be used to
+/// "indicate that a value is dynamically typed."
+///
+/// The semantics of `__eq__` and `__ne__` are such that the `obj` parameter
+/// should be any type, as opposed to a dynamically typed value. Therefore, the
+/// `object` type annotation is more appropriate.
+///
+/// ## Example
+/// ```python
+/// class Foo:
+///     def __eq__(self, obj: typing.Any):
+///         ...
+/// ```
+///
+/// Use instead:
+/// ```python
+/// class Foo:
+///     def __eq__(self, obj: object):
+///         ...
+/// ```
+/// ## References
+/// - [Python documentation](https://docs.python.org/3/library/typing.html#the-any-type)
+/// - [Mypy documentation](https://mypy.readthedocs.io/en/latest/dynamic_typing.html#any-vs-object)
+#[violation]
+pub struct AnyEqNeAnnotation {
+    method_name: String,
+}
+
+impl AlwaysAutofixableViolation for AnyEqNeAnnotation {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        let AnyEqNeAnnotation { method_name } = self;
+        format!("Prefer `object` to `Any` for the second parameter to `{method_name}`")
+    }
+
+    fn autofix_title(&self) -> String {
+        format!("Replace with `object`")
+    }
+}
+
+/// PYI032
+pub(crate) fn any_eq_ne_annotation(checker: &mut Checker, name: &str, args: &Arguments) {
+    if !matches!(name, "__eq__" | "__ne__") {
+        return;
+    }
+
+    if args.args.len() != 2 {
+        return;
+    }
+
+    let Some(annotation) = &args.args[1].annotation else {
+        return;
+    };
+
+    if !checker.semantic_model().scope().kind.is_class() {
+        return;
+    }
+
+    if checker
+        .semantic_model()
+        .match_typing_expr(annotation, "Any")
+    {
+        let mut diagnostic = Diagnostic::new(
+            AnyEqNeAnnotation {
+                method_name: name.to_string(),
+            },
+            annotation.range(),
+        );
+        if checker.patch(diagnostic.kind.rule()) {
+            // Ex) `def __eq__(self, obj: Any): ...`
+            if checker.semantic_model().is_builtin("object") {
+                diagnostic.set_fix(Fix::automatic(Edit::range_replacement(
+                    "object".to_string(),
+                    annotation.range(),
+                )));
+            }
+        }
+        checker.diagnostics.push(diagnostic);
+    }
+}

crates/ruff/src/rules/flake8_pyi/rules/mod.rs

@@ -1,3 +1,4 @@
+pub(crate) use any_eq_ne_annotation::{any_eq_ne_annotation, AnyEqNeAnnotation};
 pub(crate) use bad_version_info_comparison::{
     bad_version_info_comparison, BadVersionInfoComparison,
 };
@@ -27,6 +28,7 @@ pub(crate) use unrecognized_platform::{
     unrecognized_platform, UnrecognizedPlatformCheck, UnrecognizedPlatformName,
 };
 
+mod any_eq_ne_annotation;
 mod bad_version_info_comparison;
 mod docstring_in_stubs;
 mod duplicate_union_member;

crates/ruff/src/rules/flake8_pyi/snapshots/ruff__rules__flake8_pyi__tests__PYI032_PYI032.py.snap

@@ -0,0 +1,4 @@
+---
+source: crates/ruff/src/rules/flake8_pyi/mod.rs
+---
+

crates/ruff/src/rules/flake8_pyi/snapshots/ruff__rules__flake8_pyi__tests__PYI032_PYI032.pyi.snap

@@ -0,0 +1,42 @@
+---
+source: crates/ruff/src/rules/flake8_pyi/mod.rs
+---
+PYI032.pyi:6:29: PYI032 [*] Prefer `object` to `Any` for the second parameter to `__eq__`
+  |
+6 | class Bad:
+7 |     def __eq__(self, other: Any) -> bool: ...  # Y032
+  |                             ^^^ PYI032
+8 |     def __ne__(self, other: typing.Any) -> typing.Any: ...  # Y032
+  |
+  = help: Replace with `object`
+
+ℹ Fix
+3 3 | 
+4 4 | 
+5 5 | class Bad:
+6   |-    def __eq__(self, other: Any) -> bool: ...  # Y032
+  6 |+    def __eq__(self, other: object) -> bool: ...  # Y032
+7 7 |     def __ne__(self, other: typing.Any) -> typing.Any: ...  # Y032
+8 8 | 
+9 9 | 
+
+PYI032.pyi:7:29: PYI032 [*] Prefer `object` to `Any` for the second parameter to `__ne__`
+  |
+7 | class Bad:
+8 |     def __eq__(self, other: Any) -> bool: ...  # Y032
+9 |     def __ne__(self, other: typing.Any) -> typing.Any: ...  # Y032
+  |                             ^^^^^^^^^^ PYI032
+  |
+  = help: Replace with `object`
+
+ℹ Fix
+4 4 | 
+5 5 | class Bad:
+6 6 |     def __eq__(self, other: Any) -> bool: ...  # Y032
+7   |-    def __ne__(self, other: typing.Any) -> typing.Any: ...  # Y032
+  7 |+    def __ne__(self, other: object) -> typing.Any: ...  # Y032
+8 8 | 
+9 9 | 
+10 10 | class Good:
+
+