[pep8-naming] Ignore @override methods (N803) (#15954)

## Summary

Resolves #15925.

`N803` now checks for functions instead of parameters. In preview mode,
if a method is decorated with `@override` and the current scope is that
of a class, it will be ignored.

## Test Plan

`cargo nextest run` and `cargo insta test`.

Author: InSyncWithFoo

crates/ruff_linter/resources/test/fixtures/pep8_naming/N803.py

@@ -9,3 +9,21 @@ def method(self, _, a, A):
 
 def func(_, setUp):
     return _, setUp
+
+
+from typing import override
+
+class Extended(Class):
+    @override
+    def method(self, _, a, A): ...
+
+
+@override  # Incorrect usage
+def func(_, a, A): ...
+
+
+func = lambda _, a, A: ...
+
+
+class Extended(Class):
+    method = override(lambda self, _, a, A: ...)  # Incorrect usage

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1746,9 +1746,12 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
                 ruff::rules::parenthesize_chained_logical_operators(checker, bool_op);
             }
         }
-        Expr::Lambda(lambda_expr) => {
+        Expr::Lambda(lambda) => {
             if checker.enabled(Rule::ReimplementedOperator) {
-                refurb::rules::reimplemented_operator(checker, &lambda_expr.into());
+                refurb::rules::reimplemented_operator(checker, &lambda.into());
+            }
+            if checker.enabled(Rule::InvalidArgumentName) {
+                pep8_naming::rules::invalid_argument_name_lambda(checker, lambda);
             }
         }
         _ => {}

crates/ruff_linter/src/checkers/ast/analyze/parameter.rs

@@ -3,7 +3,7 @@ use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
 use crate::codes::Rule;
-use crate::rules::{flake8_builtins, pep8_naming, pycodestyle};
+use crate::rules::{flake8_builtins, pycodestyle};
 
 /// Run lint rules over a [`Parameter`] syntax node.
 pub(crate) fn parameter(parameter: &Parameter, checker: &mut Checker) {
@@ -14,15 +14,6 @@ pub(crate) fn parameter(parameter: &Parameter, checker: &mut Checker) {
             parameter.name.range(),
         );
     }
-    if checker.enabled(Rule::InvalidArgumentName) {
-        if let Some(diagnostic) = pep8_naming::rules::invalid_argument_name(
-            &parameter.name,
-            parameter,
-            &checker.settings.pep8_naming.ignore_names,
-        ) {
-            checker.diagnostics.push(diagnostic);
-        }
-    }
     if checker.enabled(Rule::BuiltinArgumentShadowing) {
         flake8_builtins::rules::builtin_argument_shadowing(checker, parameter);
     }

crates/ruff_linter/src/checkers/ast/analyze/statement.rs

@@ -379,6 +379,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.enabled(Rule::NonPEP695GenericFunction) {
                 pyupgrade::rules::non_pep695_generic_function(checker, function_def);
             }
+            if checker.enabled(Rule::InvalidArgumentName) {
+                pep8_naming::rules::invalid_argument_name_function(checker, function_def);
+            }
         }
         Stmt::Return(_) => {
             if checker.enabled(Rule::ReturnOutsideFunction) {

crates/ruff_linter/src/rules/pep8_naming/mod.rs

@@ -14,6 +14,7 @@ mod tests {
     use crate::registry::Rule;
     use crate::rules::pep8_naming::settings::IgnoreNames;
     use crate::rules::{flake8_import_conventions, pep8_naming};
+    use crate::settings::types::PreviewMode;
     use crate::test::test_path;
     use crate::{assert_messages, settings};
 
@@ -88,6 +89,24 @@ mod tests {
         Ok(())
     }
 
+    #[test_case(Rule::InvalidArgumentName, Path::new("N803.py"))]
+    fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
+        let snapshot = format!(
+            "preview__{}_{}",
+            rule_code.noqa_code(),
+            path.to_string_lossy()
+        );
+        let diagnostics = test_path(
+            Path::new("pep8_naming").join(path).as_path(),
+            &settings::LinterSettings {
+                preview: PreviewMode::Enabled,
+                ..settings::LinterSettings::for_rule(rule_code)
+            },
+        )?;
+        assert_messages!(snapshot, diagnostics);
+        Ok(())
+    }
+
     #[test]
     fn camelcase_imported_as_incorrect_convention() -> Result<()> {
         let diagnostics = test_path(

crates/ruff_linter/src/rules/pep8_naming/rules/invalid_argument_name.rs

@@ -1,11 +1,12 @@
-use ruff_python_ast::Parameter;
-
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, ViolationMetadata};
+use ruff_python_ast::{ExprLambda, Parameters, StmtFunctionDef};
+use ruff_python_semantic::analyze::visibility::is_override;
+use ruff_python_semantic::ScopeKind;
 use ruff_python_stdlib::str;
 use ruff_text_size::Ranged;
 
-use crate::rules::pep8_naming::settings::IgnoreNames;
+use crate::checkers::ast::Checker;
 
 /// ## What it does
 /// Checks for argument names that do not follow the `snake_case` convention.
@@ -22,6 +23,8 @@ use crate::rules::pep8_naming::settings::IgnoreNames;
 /// > mixedCase is allowed only in contexts where that’s already the
 /// > prevailing style (e.g. threading.py), to retain backwards compatibility.
 ///
+/// In [preview], overridden methods are ignored.
+///
 /// ## Example
 /// ```python
 /// def my_function(A, myArg):
@@ -35,6 +38,7 @@ use crate::rules::pep8_naming::settings::IgnoreNames;
 /// ```
 ///
 /// [PEP 8]: https://peps.python.org/pep-0008/#function-and-method-arguments
+/// [preview]: https://docs.astral.sh/ruff/preview/
 #[derive(ViolationMetadata)]
 pub(crate) struct InvalidArgumentName {
     name: String,
@@ -49,22 +53,54 @@ impl Violation for InvalidArgumentName {
 }
 
 /// N803
-pub(crate) fn invalid_argument_name(
-    name: &str,
-    parameter: &Parameter,
-    ignore_names: &IgnoreNames,
-) -> Option<Diagnostic> {
-    if !str::is_lowercase(name) {
-        // Ignore any explicitly-allowed names.
+pub(crate) fn invalid_argument_name_function(
+    checker: &mut Checker,
+    function_def: &StmtFunctionDef,
+) {
+    let semantic = checker.semantic();
+    let scope = semantic.current_scope();
+
+    if checker.settings.preview.is_enabled()
+        && matches!(scope.kind, ScopeKind::Class(_))
+        && is_override(&function_def.decorator_list, semantic)
+    {
+        return;
+    }
+
+    invalid_argument_name(checker, &function_def.parameters);
+}
+
+/// N803
+pub(crate) fn invalid_argument_name_lambda(checker: &mut Checker, lambda: &ExprLambda) {
+    let Some(parameters) = &lambda.parameters else {
+        return;
+    };
+
+    invalid_argument_name(checker, parameters);
+}
+
+/// N803
+fn invalid_argument_name(checker: &mut Checker, parameters: &Parameters) {
+    let ignore_names = &checker.settings.pep8_naming.ignore_names;
+
+    for parameter in parameters {
+        let name = parameter.name().as_str();
+
+        if str::is_lowercase(name) {
+            continue;
+        }
+
         if ignore_names.matches(name) {
-            return None;
+            continue;
         }
-        return Some(Diagnostic::new(
+
+        let diagnostic = Diagnostic::new(
             InvalidArgumentName {
                 name: name.to_string(),
             },
             parameter.range(),
-        ));
+        );
+
+        checker.diagnostics.push(diagnostic);
     }
-    None
 }

crates/ruff_linter/src/rules/pep8_naming/snapshots/ruff_linter__rules__pep8_naming__tests__N803_N803.py.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff_linter/src/rules/pep8_naming/mod.rs
-snapshot_kind: text
 ---
 N803.py:1:16: N803 Argument name `A` should be lowercase
   |
@@ -16,3 +15,31 @@ N803.py:6:28: N803 Argument name `A` should be lowercase
   |                            ^ N803
 7 |         return _, a, A
   |
+
+N803.py:18:28: N803 Argument name `A` should be lowercase
+   |
+16 | class Extended(Class):
+17 |     @override
+18 |     def method(self, _, a, A): ...
+   |                            ^ N803
+   |
+
+N803.py:22:16: N803 Argument name `A` should be lowercase
+   |
+21 | @override  # Incorrect usage
+22 | def func(_, a, A): ...
+   |                ^ N803
+   |
+
+N803.py:25:21: N803 Argument name `A` should be lowercase
+   |
+25 | func = lambda _, a, A: ...
+   |                     ^ N803
+   |
+
+N803.py:29:42: N803 Argument name `A` should be lowercase
+   |
+28 | class Extended(Class):
+29 |     method = override(lambda self, _, a, A: ...)  # Incorrect usage
+   |                                          ^ N803
+   |

crates/ruff_linter/src/rules/pep8_naming/snapshots/ruff_linter__rules__pep8_naming__tests__preview__N803_N803.py.snap

@@ -0,0 +1,37 @@
+---
+source: crates/ruff_linter/src/rules/pep8_naming/mod.rs
+---
+N803.py:1:16: N803 Argument name `A` should be lowercase
+  |
+1 | def func(_, a, A):
+  |                ^ N803
+2 |     return _, a, A
+  |
+
+N803.py:6:28: N803 Argument name `A` should be lowercase
+  |
+5 | class Class:
+6 |     def method(self, _, a, A):
+  |                            ^ N803
+7 |         return _, a, A
+  |
+
+N803.py:22:16: N803 Argument name `A` should be lowercase
+   |
+21 | @override  # Incorrect usage
+22 | def func(_, a, A): ...
+   |                ^ N803
+   |
+
+N803.py:25:21: N803 Argument name `A` should be lowercase
+   |
+25 | func = lambda _, a, A: ...
+   |                     ^ N803
+   |
+
+N803.py:29:42: N803 Argument name `A` should be lowercase
+   |
+28 | class Extended(Class):
+29 |     method = override(lambda self, _, a, A: ...)  # Incorrect usage
+   |                                          ^ N803
+   |