gh-118507 : Refactor ntpath native functions (gh-119381)

This refactoring will make future backports easier without changing behaviours,
apart from correcting a bug when passing a pipe to `ntpath.isfile`.

Author: nineteendo

Lib/test/test_genericpath.py

@@ -135,6 +135,10 @@ def test_exists(self):
         self.assertIs(self.pathmodule.exists(filename), False)
         self.assertIs(self.pathmodule.exists(bfilename), False)
 
+        if self.pathmodule is not genericpath:
+            self.assertIs(self.pathmodule.lexists(filename), False)
+            self.assertIs(self.pathmodule.lexists(bfilename), False)
+
         create_file(filename)
 
         self.assertIs(self.pathmodule.exists(filename), True)

Lib/test/test_ntpath.py

@@ -976,6 +976,27 @@ def test_isfile_driveletter(self):
             raise unittest.SkipTest('SystemDrive is not defined or malformed')
         self.assertFalse(os.path.isfile('\\\\.\\' + drive))
 
+    @unittest.skipUnless(hasattr(os, 'pipe'), "need os.pipe()")
+    def test_isfile_anonymous_pipe(self):
+        pr, pw = os.pipe()
+        try:
+            self.assertFalse(ntpath.isfile(pr))
+        finally:
+            os.close(pr)
+            os.close(pw)
+
+    @unittest.skipIf(sys.platform != 'win32', "windows only")
+    def test_isfile_named_pipe(self):
+        import _winapi
+        named_pipe = f'//./PIPE/python_isfile_test_{os.getpid()}'
+        h = _winapi.CreateNamedPipe(named_pipe,
+                                    _winapi.PIPE_ACCESS_INBOUND,
+                                    0, 1, 0, 0, 0, 0)
+        try:
+            self.assertFalse(ntpath.isfile(named_pipe))
+        finally:
+            _winapi.CloseHandle(h)
+
     @unittest.skipIf(sys.platform != 'win32', "windows only")
     def test_con_device(self):
         self.assertFalse(os.path.isfile(r"\\.\CON"))

Misc/NEWS.d/next/Core and Builtins/2024-05-22-13-51-40.gh-issue-118507.xkIQ3v.rst

@@ -0,0 +1 @@
+Fix :func:`os.path.isfile` on Windows for pipes.