bpo-38523: ignore_dangling_symlinks does not apply recursively (GH-22937)

(cherry picked from commit 5ff81da)

Co-authored-by: Zackery Spytz <[email protected]>

Author: miss-islington

Lib/shutil.py

@@ -487,12 +487,13 @@ def _copytree(entries, src, dst, symlinks, ignore, copy_function,
                     # otherwise let the copy occur. copy2 will raise an error
                     if srcentry.is_dir():
                         copytree(srcobj, dstname, symlinks, ignore,
-                                 copy_function, dirs_exist_ok=dirs_exist_ok)
+                                 copy_function, ignore_dangling_symlinks,
+                                 dirs_exist_ok)
                     else:
                         copy_function(srcobj, dstname)
             elif srcentry.is_dir():
                 copytree(srcobj, dstname, symlinks, ignore, copy_function,
-                         dirs_exist_ok=dirs_exist_ok)
+                         ignore_dangling_symlinks, dirs_exist_ok)
             else:
                 # Will raise a SpecialFileError for unsupported file types
                 copy_function(srcobj, dstname)

Lib/test/test_shutil.py

@@ -731,18 +731,25 @@ def _copy(src, dst):
 
     @os_helper.skip_unless_symlink
     def test_copytree_dangling_symlinks(self):
-        # a dangling symlink raises an error at the end
         src_dir = self.mkdtemp()
+        valid_file = os.path.join(src_dir, 'test.txt')
+        write_file(valid_file, 'abc')
+        dir_a = os.path.join(src_dir, 'dir_a')
+        os.mkdir(dir_a)
+        for d in src_dir, dir_a:
+            os.symlink('IDONTEXIST', os.path.join(d, 'broken'))
+            os.symlink(valid_file, os.path.join(d, 'valid'))
+
+        # A dangling symlink should raise an error.
         dst_dir = os.path.join(self.mkdtemp(), 'destination')
-        os.symlink('IDONTEXIST', os.path.join(src_dir, 'test.txt'))
-        os.mkdir(os.path.join(src_dir, 'test_dir'))
-        write_file((src_dir, 'test_dir', 'test.txt'), '456')
         self.assertRaises(Error, shutil.copytree, src_dir, dst_dir)
 
-        # a dangling symlink is ignored with the proper flag
+        # Dangling symlinks should be ignored with the proper flag.
         dst_dir = os.path.join(self.mkdtemp(), 'destination2')
         shutil.copytree(src_dir, dst_dir, ignore_dangling_symlinks=True)
-        self.assertNotIn('test.txt', os.listdir(dst_dir))
+        for root, dirs, files in os.walk(dst_dir):
+            self.assertNotIn('broken', files)
+            self.assertIn('valid', files)
 
         # a dangling symlink is copied if symlinks=True
         dst_dir = os.path.join(self.mkdtemp(), 'destination3')

Misc/NEWS.d/next/Library/2020-10-23-22-20-52.bpo-38523.CrkxLh.rst

@@ -0,0 +1,2 @@
+:func:`shutil.copytree` now applies the *ignore_dangling_symlinks* argument
+recursively.