[3.10] GH-100942: Fix incorrect cast in property_copy(). (GH-100965). (#101009)

(cherry picked from commit 94fc7706b7bc3d57cdd6d15bf8e8c4499ae53a69)

Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index 7f3813fc8c..4cd4283d84 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -214,6 +214,23 @@ class PropertyTests(unittest.TestCase):
             ):
                 p.__set_name__(*([0] * i))
 
+    def test_property_setname_on_property_subclass(self):
+        # https://github.com/python/cpython/issues/100942
+        # Copy was setting the name field without first
+        # verifying that the copy was an actual property
+        # instance.  As a result, the code below was
+        # causing a segfault.
+
+        class pro(property):
+            def __new__(typ, *args, **kwargs):
+                return "abcdef"
+
+        class A:
+            pass
+
+        p = property.__new__(pro)
+        p.__set_name__(A, 1)
+        np = p.getter(lambda self: 1)
 
 # Issue 5890: subclasses of property do not preserve method __doc__ strings
 class PropertySub(property):