gh-144220: Copy metadata before files in shutil.copytree()

Lib/shutil.py

@@ -553,6 +553,13 @@ def _copytree(entries, src, dst, symlinks, ignore, copy_function,
     errors = []
     use_srcentry = copy_function is copy2 or copy_function is copy
 
+    try:
+        copystat(src, dst)
+    except OSError as why:
+        # Copying file access times may fail on Windows
+        if getattr(why, 'winerror', None) is None:
+            errors.append((src, dst, str(why)))
+
     for srcentry in entries:
         if srcentry.name in ignored_names:
             continue
@@ -598,12 +605,7 @@ def _copytree(entries, src, dst, symlinks, ignore, copy_function,
             errors.extend(err.args[0])
         except OSError as why:
             errors.append((srcname, dstname, str(why)))
-    try:
-        copystat(src, dst)
-    except OSError as why:
-        # Copying file access times may fail on Windows
-        if getattr(why, 'winerror', None) is None:
-            errors.append((src, dst, str(why)))
+
     if errors:
         raise Error(errors)
     return dst

Lib/test/test_shutil.py

@@ -1099,6 +1099,25 @@ def test_copytree_subdirectory(self):
         rv = shutil.copytree(src_dir, dst_dir)
         self.assertEqual(['pol'], os.listdir(rv))
 
+    def test_copytree_xattr(self):
+        # gh-144220: copytree() must call copystat() to copy extended
+        # attributes before copying files.
+
+        src_dir = self.mkdtemp()
+        dst_dir = os.path.join(self.mkdtemp(), 'destination')
+        create_file((src_dir, 'test.txt'), '123')
+
+        def copystat(src, dst, *, follow_symlinks=True):
+            if os.path.isdir(dst) and os.listdir(dst):
+                raise Exception('Directory not empty')
+
+        with unittest.mock.patch('shutil.copystat', side_effect=copystat):
+            shutil.copytree(src_dir, dst_dir)
+        self.assertTrue(os.path.isfile(os.path.join(dst_dir, 'test.txt')))
+        actual = read_file((dst_dir, 'test.txt'))
+        self.assertEqual(actual, '123')
+
+
 class TestCopy(BaseTest, unittest.TestCase):
 
     ### shutil.copymode

Misc/NEWS.d/next/Library/2026-03-12-15-48-35.gh-issue-144220.bxjFNf.rst

@@ -0,0 +1,3 @@
+:func:`shutil.copytree` now copies directory metadata before copying files. It
+prevents an error when setting an extended attribute (``bcachefs.casefold``) on
+an non-empty directory. Patch by Victor Stinner.