[3.8] bpo-38878: Fix os.PathLike __subclasshook__ (GH-17336) (GH-17684)
https://bugs.python.org/issue38878
diff --git a/Lib/os.py b/Lib/os.py
index 52d3f1d..253cad1 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -26,6 +26,8 @@
import sys
import stat as st
+from _collections_abc import _check_methods
+
_names = sys.builtin_module_names
# Note: more names are added to __all__ later.
@@ -1070,7 +1072,9 @@
@classmethod
def __subclasshook__(cls, subclass):
- return hasattr(subclass, '__fspath__')
+ if cls is PathLike:
+ return _check_methods(subclass, '__fspath__')
+ return NotImplemented
if name == 'nt':
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 4a076e3..11454b2 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -4017,6 +4017,14 @@
self.assertRaises(ZeroDivisionError, self.fspath,
FakePath(ZeroDivisionError()))
+ def test_pathlike_subclasshook(self):
+ # bpo-38878: subclasshook causes subclass checks
+ # true on abstract implementation.
+ class A(os.PathLike):
+ pass
+ self.assertFalse(issubclass(FakePath, A))
+ self.assertTrue(issubclass(FakePath, os.PathLike))
+
class TimesTests(unittest.TestCase):
def test_times(self):