Add side effect note; apply review suggestions for test

Co-authored-by: Jelle Zijlstra <[email protected]>

Author: encukou

Doc/whatsnew/3.15.rst

@@ -207,6 +207,7 @@ Other language changes
 * The :attr:`~object.__dict__` and :attr:`!__weakref__` descriptors now use a
   single descriptor instance per interpreter, shared across all types that
   need them.
+  This speeds up class creation, and helps avoid reference cycles.
   (Contributed by Petr Viktorin in :gh:`135228`.)
 
 

Lib/test/test_descr.py

@@ -6070,11 +6070,11 @@ class IntSubclass(int):
                     None,
                 )
         with self.assertRaises(AttributeError):
-            print(weakref_descriptor.__get__(True, bool))
+            weakref_descriptor.__get__(True, bool)
         with self.assertRaises(AttributeError):
-            print(weakref_descriptor.__get__(SlotClass(), SlotClass))
+            weakref_descriptor.__get__(SlotClass(), SlotClass)
         with self.assertRaises(AttributeError):
-            print(weakref_descriptor.__get__(IntSubclass(), IntSubclass))
+            weakref_descriptor.__get__(IntSubclass(), IntSubclass)
 
 
 if __name__ == "__main__":

Misc/NEWS.d/next/Core_and_Builtins/2025-08-05-10-22-15.gh-issue-136966.J5lrE0.rst

@@ -1,3 +1,4 @@
 The :attr:`object.__dict__` and :attr:`!__weakref__` descriptors now use a
 single descriptor instance per interpreter, shared across all types that
 need them.
+This speeds up class creation, and helps avoid reference cycles.