bpo-38894: Fix pathlib.Path.glob in the presence of symlinks and insufficient permissions (GH-18815)

Co-authored-by: Matt Wozniski <mwozniski@bloomberg.net>
(cherry picked from commit eb7560a73d46800e4ade4a8869139b48e6c92811)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/Lib/test/test_pathlib.py b/Lib/test/test_pathlib.py
index 97fc5d8..3622694 100644
--- a/Lib/test/test_pathlib.py
+++ b/Lib/test/test_pathlib.py
@@ -1508,6 +1508,42 @@ class _BasePathTest(object):
         self.assertEqual(set(p.glob("dirA/../file*")), { P(BASE, "dirA/../fileA") })
         self.assertEqual(set(p.glob("../xyzzy")), set())
 
+    @support.skip_unless_symlink
+    def test_glob_permissions(self):
+        # See bpo-38894
+        P = self.cls
+        base = P(BASE) / 'permissions'
+        base.mkdir()
+
+        file1 = base / "file1"
+        file1.touch()
+        file2 = base / "file2"
+        file2.touch()
+
+        subdir = base / "subdir"
+
+        file3 = base / "file3"
+        file3.symlink_to(subdir / "other")
+
+        # Patching is needed to avoid relying on the filesystem
+        # to return the order of the files as the error will not
+        # happen if the symlink is the last item.
+
+        with mock.patch("os.scandir") as scandir:
+            scandir.return_value = sorted(os.scandir(base))
+            self.assertEqual(len(set(base.glob("*"))), 3)
+
+        subdir.mkdir()
+
+        with mock.patch("os.scandir") as scandir:
+            scandir.return_value = sorted(os.scandir(base))
+            self.assertEqual(len(set(base.glob("*"))), 4)
+
+        subdir.chmod(000)
+
+        with mock.patch("os.scandir") as scandir:
+            scandir.return_value = sorted(os.scandir(base))
+            self.assertEqual(len(set(base.glob("*"))), 4)
 
     def _check_resolve(self, p, expected, strict=True):
         q = p.resolve(strict)