parent approach

crates/ruff/tests/lint.rs

@@ -2321,9 +2321,7 @@ fn a005_module_shadowing_strict() -> Result<()> {
         ----- stdout -----
         abc/__init__.py:1:1: A005 Module `abc` shadows a Python standard-library module
         collections/__init__.py:1:1: A005 Module `collections` shadows a Python standard-library module
-        collections/abc/__init__.py:1:1: A005 Module `collections` shadows a Python standard-library module
-        collections/foobar/__init__.py:1:1: A005 Module `collections` shadows a Python standard-library module
-        Found 4 errors.
+        Found 2 errors.
 
         ----- stderr -----
         ");

crates/ruff_linter/src/rules/flake8_builtins/rules/stdlib_module_shadowing.rs

@@ -80,24 +80,24 @@ pub(crate) fn stdlib_module_shadowing(
     };
 
     // convert a filesystem path like `foobar/collections/abc` to a reversed sequence of modules
-    // like `["foobar", "collections", "abc"]`, stripping anything that's not a normal component
+    // like `["abc", "collections", "foobar"]`, stripping anything that's not a normal component
     let mut components = path
         .components()
         .filter(|c| matches!(c, Component::Normal(_)))
-        .map(|c| c.as_os_str().to_string_lossy());
+        .map(|c| c.as_os_str().to_string_lossy())
+        .rev();
 
-    // in strict mode, check the last path component, matching the upstream rule. in non-strict
-    // mode, only compare the first component (the root package)
-    let module_name = if settings.flake8_builtins.builtins_strict_checking {
-        components.last()?
-    } else {
-        components.next()?
-    };
+    let module_name = components.next()?;
 
     if is_allowed_module(settings, &module_name) {
         return None;
     }
 
+    // not allowed generally, but check for a parent in non-strict mode
+    if !settings.flake8_builtins.builtins_strict_checking && components.next().is_some() {
+        return None;
+    }
+
     Some(Diagnostic::new(
         StdlibModuleShadowing {
             name: module_name.to_string(),