[3.13] GH-117195: Avoid assertion error in `object.__sizeof__` (GH-117220) (GH-119456)

diff --git a/Lib/test/test_long.py b/Lib/test/test_long.py
index d299c34cec076d0468461e7330b3508e736c1470..41b973da2c7df09c728a3f5c8d6abd3536d2b04b 100644 (file)
--- a/Lib/test/test_long.py
+++ b/Lib/test/test_long.py
@@ -1639,6 +1639,8 @@ class LongTest(unittest.TestCase):
                     MyInt.__basicsize__ + MyInt.__itemsize__ * ndigits
                 )
 
+        # GH-117195 -- This shouldn't crash
+        object.__sizeof__(1)
 
 if __name__ == "__main__":
     unittest.main()

diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-03-25-15-07-01.gh-issue-117195.OWakgD.rst b/Misc/NEWS.d/next/Core and Builtins/2024-03-25-15-07-01.gh-issue-117195.OWakgD.rst
new file mode 100644 (file)
index 0000000..ae1e5ac
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2024-03-25-15-07-01.gh-issue-117195.OWakgD.rst
@@ -0,0 +1,2 @@
+Avoid assertion failure for debug builds when calling
+``object.__sizeof__(1)``

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index b7c3fcf47f23fc1fe0deaca8549fad35fb8fe805..4af49714b492fd7347b1722a898dab66196cd228 100644 (file)
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -7037,8 +7037,11 @@ object___sizeof___impl(PyObject *self)
 
     res = 0;
     isize = Py_TYPE(self)->tp_itemsize;
-    if (isize > 0)
-        res = Py_SIZE(self) * isize;
+    if (isize > 0) {
+        /* This assumes that ob_size is valid if tp_itemsize is not 0,
+         which isn't true for PyLongObject. */
+        res = _PyVarObject_CAST(self)->ob_size * isize;
+    }
     res += Py_TYPE(self)->tp_basicsize;
 
     return PyLong_FromSsize_t(res);