Fix bug when PurePath takes and ignores **kwargs

Author: uriyyo

Lib/pathlib.py

@@ -650,7 +650,7 @@ class PurePath(object):
         '_str', '_hash', '_pparts', '_cached_cparts',
     )
 
-    def __new__(cls, *args):
+    def __new__(cls, *args, **kwargs):
         """Construct a PurePath from one or several strings and or existing
         PurePath objects.  The strings and path objects are combined so as
         to yield a canonicalized path, which is incorporated into the
@@ -660,6 +660,9 @@ def __new__(cls, *args):
             cls = PureWindowsPath if os.name == 'nt' else PurePosixPath
         return cls._from_parts(args)
 
+    def __init__(self, *_):
+        pass  # bpo-29847
+
     def __reduce__(self):
         # Using the parts tuple helps share interned path parts
         # when pickling related paths.
@@ -1071,9 +1074,6 @@ def __new__(cls, *args, **kwargs):
         self._init()
         return self
 
-    def __init__(self, *_):
-        pass  # bpo-29847
-
     def _init(self,
               # Private non-constructor arguments
               template=None,

Lib/test/test_pathlib.py

@@ -681,6 +681,21 @@ def test_pickling_common(self):
             self.assertEqual(hash(pp), hash(p))
             self.assertEqual(str(pp), str(p))
 
+    def test_kwargs(self):
+        with self.assertRaisesRegex(TypeError, 'got an unexpected keyword argument'):
+            self.cls(arg=None)
+
+    def test_subclass_kwargs(self):
+        class _PathSubclass(self.cls):
+            _flavour = self.cls()._flavour
+
+            def __init__(self, *args, **kwargs):
+                self.kwargs = kwargs
+
+        _kwargs = {"a": 1, "b": 2}
+        p = _PathSubclass(**_kwargs)
+        self.assertEqual(p.kwargs, _kwargs)
+
 
 class PurePosixPathTest(_BasePurePathTest, unittest.TestCase):
     cls = pathlib.PurePosixPath
@@ -2300,21 +2315,6 @@ def test_complex_symlinks_relative(self):
     def test_complex_symlinks_relative_dot_dot(self):
         self._check_complex_symlinks(os.path.join('dirA', '..'))
 
-    def test_kwargs(self):
-        with self.assertRaisesRegex(TypeError, 'got an unexpected keyword argument'):
-            self.cls(arg=None)
-
-    def test_subclass_kwargs(self):
-        class _PathSubclass(self.cls):
-            _flavour = self.cls()._flavour
-
-            def __init__(self, *args, **kwargs):
-                self.kwargs = kwargs
-
-        _kwargs = {"a": 1, "b": 2}
-        p = _PathSubclass(**_kwargs)
-        self.assertEqual(p.kwargs, _kwargs)
-
 
 class PathTest(_BasePathTest, unittest.TestCase):
     cls = pathlib.Path