bpo-38761: Register WeakSet as a MutableSet (GH-17104)
diff --git a/Lib/test/test_weakset.py b/Lib/test/test_weakset.py
index 569facd..49a9b5c 100644
--- a/Lib/test/test_weakset.py
+++ b/Lib/test/test_weakset.py
@@ -2,6 +2,7 @@
from weakref import WeakSet
import string
from collections import UserString as ustr
+from collections.abc import Set, MutableSet
import gc
import contextlib
@@ -437,6 +438,10 @@
def test_repr(self):
assert repr(self.s) == repr(self.s.data)
+ def test_abc(self):
+ self.assertIsInstance(self.s, Set)
+ self.assertIsInstance(self.s, MutableSet)
+
if __name__ == "__main__":
unittest.main()
diff --git a/Lib/weakref.py b/Lib/weakref.py
index d17b3ed..e3c2ce2 100644
--- a/Lib/weakref.py
+++ b/Lib/weakref.py
@@ -33,6 +33,9 @@
"WeakSet", "WeakMethod", "finalize"]
+_collections_abc.Set.register(WeakSet)
+_collections_abc.MutableSet.register(WeakSet)
+
class WeakMethod(ref):
"""
A custom `weakref.ref` subclass which simulates a weak reference to