Issue #20589: Invoking Path.owner() and Path.group() on Windows now raise

NotImplementedError instead of ImportError.

Lib/pathlib.py

@@ -1425,3 +1425,9 @@ class PosixPath(Path, PurePosixPath):
 
 class WindowsPath(Path, PureWindowsPath):
     __slots__ = ()
+
+    def owner(self):
+        raise NotImplementedError("Path.owner() is unsupported on this system")
+
+    def group(self):
+        raise NotImplementedError("Path.group() is unsupported on this system")

Lib/test/test_pathlib.py

@@ -1156,6 +1156,15 @@ class PureWindowsPathTest(_BasePurePathTest, unittest.TestCase):
         # UNC paths are never reserved
         self.assertIs(False, P('//my/share/nul/con/aux').is_reserved())
 
+    def test_owner(self):
+        P = self.cls
+        with self.assertRaises(NotImplementedError):
+            P('c:/').owner()
+
+    def test_group(self):
+        P = self.cls
+        with self.assertRaises(NotImplementedError):
+            P('c:/').group()
 
 class PurePathTest(_BasePurePathTest, unittest.TestCase):
     cls = pathlib.PurePath

Misc/NEWS

@@ -91,6 +91,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #20589: Invoking Path.owner() and Path.group() on Windows now raise
+  NotImplementedError instead of ImportError.
+
 - Issue #26177: Fixed the keys() method for Canvas and Scrollbar widgets.
 
 - Issue #15068: Got rid of excessive buffering in the fileinput module.