gh-93334: Fix homonym edge case in PathFinder.find_spec

python · brettcannon · Sep 5, 2025 · Oct 8, 2022 · Oct 8, 2022 · Apr 8, 2023
commit 17ddcd0a5211099e3010f9d72b84629082a0d8e6
@@ -1347,7 +1347,7 @@ def __init__(self, name, path, path_finder):
     def _find_parent_path_names(self):
         """Returns a tuple of (parent-module-name, parent-path-attr-name)"""
         parent, dot, me = self._name.rpartition('.')
-        if dot == '':
+        if dot == '' or parent not in sys.modules:
             # This is a top-level module. sys.path contains the parent path.
             return 'sys', 'path'
         # Not a top-level module. parent-module.__path__ contains the

diff --git a/Lib/test/test_importlib/namespace_pkgs/homonym/README.md b/Lib/test/test_importlib/namespace_pkgs/homonym/README.md
@@ -0,0 +1,2 @@
+This directory should not be a package, but should share a name with an
+unrelated subpackage.
diff --git a/Lib/test/test_importlib/namespace_pkgs/project4/homonym.py b/Lib/test/test_importlib/namespace_pkgs/project4/homonym.py
@@ -0,0 +1 @@
+attr = 'homonym'
@@ -316,6 +316,17 @@ def test_module_before_namespace_package(self):
         self.assertEqual(a_test.attr, 'in module')
 
 
+class DirectoryHomonym(NamespacePackageTest):
+    paths = ['']
+
+    def test_namespace_package_submodule_homonym(self):
+        submodule_path = 'project4.homonym'
+        got = importlib.machinery.PathFinder.find_spec(submodule_path)
+        self.assertEqual(got.name, submodule_path)
+        self.assertIsNone(got.loader)
+        self.assertTrue(got.submodule_search_locations[0].endswith('homonym'))
+
+
 class ReloadTests(NamespacePackageTest):
     paths = ['portion1']
 

diff --git a/Misc/NEWS.d/next/Library/2022-10-08-14-56-07.gh-issue-93334.0KUm8d.rst b/Misc/NEWS.d/next/Library/2022-10-08-14-56-07.gh-issue-93334.0KUm8d.rst
@@ -0,0 +1,3 @@
+Prevent :exc:`KeyError` thrown by :meth:`importlib.machinery.PathFinder.find_spec`
+when a directory that is not a module shares a name with a namespace package
+submodule, and where a `path` argument is not provided.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		This directory should not be a package, but should share a name with an
Comment thread brettcannon marked this conversation as resolved.
		unrelated subpackage.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		attr = 'homonym'
Comment thread brettcannon marked this conversation as resolved. Outdated