[3.15] gh-158998: Fix os.statx() ignoring follow_symlinks=False (GH-158999) (#160996)

(cherry picked from commit b84e0b7)

Co-authored-by: Jonathan J. Helmus <jjhelmus@gmail.com>

Author: miss-islington

Lib/test/test_os/test_os.py

@@ -752,13 +752,13 @@ def test_stat_result_pickle(self):
                 unpickled = pickle.loads(p)
                 self.assertEqual(result, unpickled)
 
-    def check_statx_attributes(self, filename):
+    def check_statx_attributes(self, filename, follow_symlinks=True):
         maximal_mask = 0
         for name in dir(os):
             if name.startswith('STATX_'):
                 maximal_mask |= getattr(os, name)
-        result = os.statx(filename, maximal_mask)
-        stat_result = os.stat(filename)
+        result = os.statx(filename, maximal_mask, follow_symlinks=follow_symlinks)
+        stat_result = os.stat(filename, follow_symlinks=follow_symlinks)
 
         time_attributes = ('stx_atime', 'stx_btime', 'stx_ctime', 'stx_mtime')
         # gh-83714: stx_btime can be None on tmpfs even if STATX_BTIME mask
@@ -873,6 +873,28 @@ def getmask(name):
     def test_statx_attributes(self):
         self.check_statx_attributes(self.fname)
 
+    @unittest.skipUnless(hasattr(os, 'statx'), 'test needs os.statx()')
+    @os_helper.skip_unless_symlink
+    def test_statx_attributes_symlink(self):
+        link = self.fname + '-link'
+        os.symlink(os.path.basename(self.fname), link)
+        self.addCleanup(os_helper.unlink, link)
+
+        with self.subTest(broken=False, follow_symlinks=True):
+            self.check_statx_attributes(link, follow_symlinks=True)
+
+        with self.subTest(broken=False, follow_symlinks=False):
+            self.check_statx_attributes(link, follow_symlinks=False)
+
+        # break the symlink
+        os.unlink(self.fname)
+        with self.subTest(broken=True, follow_symlinks=True):
+            with self.assertRaises(FileNotFoundError):
+                os.statx(link, os.STATX_BASIC_STATS, follow_symlinks=True)
+
+        with self.subTest(broken=True, follow_symlinks=False):
+            self.check_statx_attributes(link, follow_symlinks=False)
+
     @unittest.skipUnless(hasattr(os, 'statx'), 'test needs os.statx()')
     def test_statx_attributes_bytes(self):
         try:

Misc/NEWS.d/next/Library/2026-10-08-21-02-38.gh-issue-158998.DZYJI7.rst

@@ -0,0 +1 @@
+Fix :func:`os.statx` ignoring the *follow_symlinks* argument.

Modules/posixmodule.c

@@ -3709,6 +3709,9 @@ os_statx_impl(PyObject *module, path_t *path, unsigned int mask, int flags,
                      "use dir_fd kwarg instead of AT_EMPTY_PATH flag");
         return NULL;
     }
+    if (!follow_symlinks) {
+        flags |= AT_SYMLINK_NOFOLLOW;
+    }
 
     /* Future bits may refer to members beyond the current size of struct
        statx, so we need to mask them off to prevent memory corruption. */