gh-109782: Ensure os.path.isdir has the same signature on all platforms

Lib/test/test_ntpath.py

@@ -1,4 +1,5 @@
 import inspect
+import genericpath
 import ntpath
 import os
 import string
@@ -998,6 +999,16 @@ def test_fast_paths_in_use(self):
         self.assertTrue(os.path.exists is nt._path_exists)
         self.assertFalse(inspect.isfunction(os.path.exists))
 
+    def test_signatures_identical_to_other_platforms(self):
+        for func_name in "isdir", "isfile", "islink", "exists":
+            with self.subTest(func_name=func_name):
+                ntpath_function = getattr(ntpath, func_name)
+                genericpath_function = getattr(genericpath, func_name)
+                self.assertEqual(
+                    inspect.signature(ntpath_function),
+                    inspect.signature(genericpath_function)
+                )
+
     @unittest.skipIf(os.name != 'nt', "Dev Drives only exist on Win32")
     def test_isdevdrive(self):
         # Result may be True or False, but shouldn't raise

Misc/NEWS.d/next/Library/2023-09-24-16-43-33.gh-issue-109782.gMC_7z.rst

@@ -0,0 +1,2 @@
+Ensure the signature of :func:`os.path.isdir` is identical on all platforms.
+Patch by Amin Alaee.

Modules/posixmodule.c

@@ -4912,25 +4912,25 @@ os__path_splitroot_impl(PyObject *module, path_t *path)
 /*[clinic input]
 os._path_isdir
 
-    path: 'O'
+    s: 'O'
 
 Return true if the pathname refers to an existing directory.
 
 [clinic start generated code]*/
 
 static PyObject *
-os__path_isdir_impl(PyObject *module, PyObject *path)
-/*[clinic end generated code: output=00faea0af309669d input=b1d2571cf7291aaf]*/
+os__path_isdir_impl(PyObject *module, PyObject *s)
+/*[clinic end generated code: output=9d87ab3c8b8a4e61 input=c17f7ef21d22d64e]*/
 {
     HANDLE hfile;
     BOOL close_file = TRUE;
     FILE_BASIC_INFO info;
-    path_t _path = PATH_T_INITIALIZE("isdir", "path", 0, 1);
+    path_t _path = PATH_T_INITIALIZE("isdir", "s", 0, 1);
     int result;
     BOOL slow_path = TRUE;
     FILE_STAT_BASIC_INFORMATION statInfo;
 
-    if (!path_converter(path, &_path)) {
+    if (!path_converter(s, &_path)) {
         path_cleanup(&_path);
         if (PyErr_ExceptionMatches(PyExc_ValueError)) {
             PyErr_Clear();