Address Sam's reviews

Author: Fidget-Spinner

Include/internal/pycore_dict.h

@@ -323,7 +323,7 @@ _PyInlineValuesSize(PyTypeObject *tp)
 int
 _PyDict_DetachFromObject(PyDictObject *dict, PyObject *obj);
 
-PyDictObject *_PyObject_materialize_managed_dict_lock_held(PyObject *);
+PyDictObject *_PyObject_MaterializeManagedDict_LockHeld(PyObject *);
 
 #ifdef __cplusplus
 }

Objects/dictobject.c

@@ -6709,7 +6709,7 @@ make_dict_from_instance_attributes(PyInterpreterState *interp,
 }
 
 PyDictObject *
-_PyObject_materialize_managed_dict_lock_held(PyObject *obj)
+_PyObject_MaterializeManagedDict_LockHeld(PyObject *obj)
 {
     ASSERT_WORLD_STOPPED_OR_OBJ_LOCKED(obj);
 
@@ -6740,7 +6740,7 @@ _PyObject_MaterializeManagedDict(PyObject *obj)
         goto exit;
     }
 #endif
-    dict = _PyObject_materialize_managed_dict_lock_held(obj);
+    dict = _PyObject_MaterializeManagedDict_LockHeld(obj);
 
 #ifdef Py_GIL_DISABLED
 exit:

Objects/typeobject.c

@@ -6604,34 +6604,11 @@ compatible_for_assignment(PyTypeObject* oldto, PyTypeObject* newto, const char*
     return 0;
 }
 
-static int
-object_set_class(PyObject *self, PyObject *value, void *closure)
-{
-
-    if (value == NULL) {
-        PyErr_SetString(PyExc_TypeError,
-                        "can't delete __class__ attribute");
-        return -1;
-    }
-    if (!PyType_Check(value)) {
-        PyErr_Format(PyExc_TypeError,
-          "__class__ must be set to a class, not '%s' object",
-          Py_TYPE(value)->tp_name);
-        return -1;
-    }
-    PyTypeObject *newto = (PyTypeObject *)value;
 
-    if (PySys_Audit("object.__setattr__", "OsO",
-                    self, "__class__", value) < 0) {
-        return -1;
-    }
 
-#ifdef Py_GIL_DISABLED
-    PyInterpreterState *interp = _PyInterpreterState_GET();
-    // The real Py_TYPE(self) (`oldto`) may have changed from
-    // underneath us in another thread, so we stop the world.
-    _PyEval_StopTheWorld(interp);
-#endif
+static int
+object_set_class_no_world_stopped(PyObject *self, PyTypeObject *newto, PyTypeObject **oldto_p)
+{
     PyTypeObject *oldto = Py_TYPE(self);
 
     /* In versions of CPython prior to 3.5, the code in
@@ -6690,7 +6667,7 @@ object_set_class(PyObject *self, PyObject *value, void *closure)
         PyErr_Format(PyExc_TypeError,
                      "__class__ assignment only supported for mutable types "
                      "or ModuleType subclasses");
-        goto err;
+        return -1;
     }
 
     if (compatible_for_assignment(oldto, newto, "__class__")) {
@@ -6699,9 +6676,9 @@ object_set_class(PyObject *self, PyObject *value, void *closure)
         if (oldto->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
             PyDictObject *dict = _PyObject_GetManagedDict(self);
             if (dict == NULL) {
-                dict = _PyObject_materialize_managed_dict_lock_held(self);
+                dict = _PyObject_MaterializeManagedDict_LockHeld(self);
                 if (dict == NULL) {
-                    goto err;
+                    return -1;
                 }
             }
 
@@ -6714,35 +6691,67 @@ object_set_class(PyObject *self, PyObject *value, void *closure)
                    dict->ma_values != _PyObject_InlineValues(self));
 
             if (_PyDict_DetachFromObject(dict, self) < 0) {
-                goto err;
+                return -1;
             }
 
         }
         if (newto->tp_flags & Py_TPFLAGS_HEAPTYPE) {
             Py_INCREF(newto);
         }
 
-#ifdef Py_GIL_DISABLED
-        _PyEval_StartTheWorld(interp);
-#endif
         Py_SET_TYPE(self, newto);
 
-        if (oldto->tp_flags & Py_TPFLAGS_HEAPTYPE) {
-            Py_DECREF(oldto);
-        }
-
-        RARE_EVENT_INC(set_class);
+        *oldto_p = oldto;
 
         return 0;
     }
     else {
-        goto err;
+        return -1;
     }
-err:
+}
+
+static int
+object_set_class(PyObject *self, PyObject *value, void *closure)
+{
+
+    if (value == NULL) {
+        PyErr_SetString(PyExc_TypeError,
+                        "can't delete __class__ attribute");
+        return -1;
+    }
+    if (!PyType_Check(value)) {
+        PyErr_Format(PyExc_TypeError,
+          "__class__ must be set to a class, not '%s' object",
+          Py_TYPE(value)->tp_name);
+        return -1;
+    }
+    PyTypeObject *newto = (PyTypeObject *)value;
+
+    if (PySys_Audit("object.__setattr__", "OsO",
+                    self, "__class__", value) < 0) {
+        return -1;
+    }
+
+#ifdef Py_GIL_DISABLED
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    // The real Py_TYPE(self) (`oldto`) may have changed from
+    // underneath us in another thread, so we stop the world.
+    _PyEval_StopTheWorld(interp);
+#endif
+    PyTypeObject *oldto;
+    int res = object_set_class_no_world_stopped(self, newto, &oldto);
 #ifdef Py_GIL_DISABLED
     _PyEval_StartTheWorld(interp);
 #endif
-    return -1;
+    if (res == 0) {
+        if (oldto->tp_flags & Py_TPFLAGS_HEAPTYPE) {
+            Py_DECREF(oldto);
+        }
+
+        RARE_EVENT_INC(set_class);
+        return 0;
+    }
+    return res;
 }
 
 static PyGetSetDef object_getsets[] = {