Support PEP 562 (#841)

resources/test/fixtures/N807.py

@@ -10,6 +10,27 @@ def good__():
     pass
 
 
+def nested():
+    def __bad__():
+        pass
+
+    def __good():
+        pass
+
+    def good__():
+        pass
+
+
 class Class:
     def __good__(self):
         pass
+
+
+# https://peps.python.org/pep-0562/
+def __getattr__(name):
+    pass
+
+
+# https://peps.python.org/pep-0562/
+def __dir__():
+    pass

src/pep8_naming/checks.rs

@@ -132,6 +132,11 @@ pub fn dunder_function_name(scope: &Scope, stmt: &Stmt, name: &str) -> Option<Ch
         return None;
     }
     if name.starts_with("__") && name.ends_with("__") {
+        // Allowed under PEP 562 (https://peps.python.org/pep-0562/).
+        if matches!(scope.kind, ScopeKind::Module) && (name == "__getattr__" || name == "__dir__") {
+            return None;
+        }
+
         return Some(Check::new(
             CheckKind::DunderFunctionName,
             Range::from_located(stmt),

src/snapshots/ruff__linter__tests__N807_N807.py.snap

@@ -10,4 +10,12 @@ expression: checks
     row: 5
     column: 0
   fix: ~
+- kind: DunderFunctionName
+  location:
+    row: 14
+    column: 4
+  end_location:
+    row: 17
+    column: 4
+  fix: ~