[Python-checkins] [3.8] bpo-38878: Fix os.PathLike subclasshook (GH-17336) (GH-17684)

Mon Dec 23 13:31:07 EST 2019

https://github.com/python/cpython/commit/0846e5d4603434c2bbf8a528677cf1ff3fe29b95
commit: 0846e5d4603434c2bbf8a528677cf1ff3fe29b95
branch: 3.8
author: Bar Harel <bzvi7919 at gmail.com>
committer: Ivan Levkivskyi <levkivskyi at gmail.com>
date: 2019年12月23日T18:31:00Z
summary:
[3.8] bpo-38878: Fix os.PathLike __subclasshook__ (GH-17336) (GH-17684)
https://bugs.python.org/issue38878
files:
A Misc/NEWS.d/next/Library/2019-11-22-12-08-52.bpo-38878.EJ0cFf.rst
M Lib/os.py
M Lib/test/test_os.py

diff --git a/Lib/os.py b/Lib/os.py
index 52d3f1d741585..253cad1a59f35 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 @@ def __fspath__(self):
 
 @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 4a076e3bbf542..11454b2e88ff6 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -4017,6 +4017,14 @@ def test_bad_pathlike(self):
 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):
diff --git a/Misc/NEWS.d/next/Library/2019-11-22-12-08-52.bpo-38878.EJ0cFf.rst b/Misc/NEWS.d/next/Library/2019-11-22-12-08-52.bpo-38878.EJ0cFf.rst
new file mode 100644
index 0000000000000..9cbdf08dd53e3
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-11-22-12-08-52.bpo-38878.EJ0cFf.rst
@@ -0,0 +1,2 @@
+Fixed __subclasshook__ of :class:`os.PathLike` to return a correct result
+upon inheritence. Patch by Bar Harel.


[Python-checkins] [3.8] bpo-38878: Fix os.PathLike __subclasshook__ (GH-17336) (GH-17684)

[Python-checkins] [3.8] bpo-38878: Fix os.PathLike subclasshook (GH-17336) (GH-17684)