Speedup os.path.isjunction and os.path.lexists on Windows with a …

…native implementation.

Lib/ntpath.py

@@ -279,19 +279,11 @@ def dirname(p):
 
 # Is a path a junction?
 
-if hasattr(os.stat_result, 'st_reparse_tag'):
-    def isjunction(path):
-        """Test whether a path is a junction"""
-        try:
-            st = os.lstat(path)
-        except (OSError, ValueError, AttributeError):
-            return False
-        return bool(st.st_reparse_tag == stat.IO_REPARSE_TAG_MOUNT_POINT)
-else:
-    def isjunction(path):
-        """Test whether a path is a junction"""
-        os.fspath(path)
-        return False
+def isjunction(path):
+    """Test whether a path is a junction
+    Junctions are not supported on the current platform"""
+    os.fspath(path)
+    return False
 
 
 # Being true for dangling symbolic links is also useful.
@@ -875,9 +867,11 @@ def commonpath(paths):
     from nt import _path_isdir as isdir
     from nt import _path_isfile as isfile
     from nt import _path_islink as islink
+    from nt import _path_isjunction as isjunction
     from nt import _path_exists as exists
+    from nt import _path_lexists as lexists
 except ImportError:
-    # Use genericpath.* as imported above
+    # Use Python version or genericpath.* as imported above
     pass
 
 

Lib/test/test_ntpath.py

@@ -1016,8 +1016,12 @@ def test_fast_paths_in_use(self):
         self.assertFalse(inspect.isfunction(os.path.isfile))
         self.assertTrue(os.path.islink is nt._path_islink)
         self.assertFalse(inspect.isfunction(os.path.islink))
+        self.assertTrue(os.path.isjunction is nt._path_isjunction)
+        self.assertFalse(inspect.isfunction(os.path.isjunction))
         self.assertTrue(os.path.exists is nt._path_exists)
         self.assertFalse(inspect.isfunction(os.path.exists))
+        self.assertTrue(os.path.lexists is nt._path_lexists)
+        self.assertFalse(inspect.isfunction(os.path.lexists))
 
     @unittest.skipIf(os.name != 'nt', "Dev Drives only exist on Win32")
     def test_isdevdrive(self):

Misc/NEWS.d/next/Core and Builtins/2024-05-08-18-33-07.gh-issue-118507.OCQsAY.rst

@@ -0,0 +1 @@
+Speedup :func:`os.path.isjunction` and :func:`os.path.lexists` on Windows with a native implementation.

Modules/posixmodule.c

@@ -5165,6 +5165,25 @@ os__path_exists_impl(PyObject *module, PyObject *path)
 }
 
 
+/*[clinic input]
+os._path_lexists -> bool
+
+    path: object
+    /
+
+Test whether a path exists.  Returns True for broken symbolic links.
+
+[clinic start generated code]*/
+
+static int
+os__path_lexists_impl(PyObject *module, PyObject *path)
+/*[clinic end generated code: output=fec4a91cf4ffccf1 input=8843d4d6d4e7c779]*/
+{
+    path_t _path = PATH_T_INITIALIZE("_path_lexists", "path", 0, 1);
+    return _testFileExists(&_path, path, FALSE);
+}
+
+
 /*[clinic input]
 os._path_isdir -> bool
 
@@ -5218,6 +5237,23 @@ os__path_islink_impl(PyObject *module, PyObject *path)
     return _testFileType(&_path, path, PY_IFLNK);
 }
 
+/*[clinic input]
+os._path_isjunction -> bool
+
+    path: object
+
+Test whether a path is a junction
+
+[clinic start generated code]*/
+
+static int
+os__path_isjunction_impl(PyObject *module, PyObject *path)
+/*[clinic end generated code: output=f1d51682a077654d input=103ccedcdb714f11]*/
+{
+    path_t _path = PATH_T_INITIALIZE("_path_isjunction", "path", 0, 1);
+    return _testFileType(&_path, path, PY_IFMNT);
+}
+
 #undef PY_IFREG
 #undef PY_IFDIR
 #undef PY_IFLNK
@@ -16009,7 +16045,9 @@ static PyMethodDef posix_methods[] = {
     OS__PATH_ISDIR_METHODDEF
     OS__PATH_ISFILE_METHODDEF
     OS__PATH_ISLINK_METHODDEF
+    OS__PATH_ISJUNCTION_METHODDEF
     OS__PATH_EXISTS_METHODDEF
+    OS__PATH_LEXISTS_METHODDEF
     {NULL,              NULL}            /* Sentinel */
 };