Issue #1721812: Binary operations and copy operations on set/frozenset
subclasses need to return the base type, not the subclass itself.
diff --git a/Objects/setobject.c b/Objects/setobject.c
index d24e1af..d08ff5f 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1017,6 +1017,18 @@
return (PyObject *)so;
}
+static PyObject *
+make_new_set_basetype(PyTypeObject *type, PyObject *iterable)
+{
+ if (type != &PySet_Type && type != &PyFrozenSet_Type) {
+ if (PyType_IsSubtype(type, &PySet_Type))
+ type = &PySet_Type;
+ else
+ type = &PyFrozenSet_Type;
+ }
+ return make_new_set(type, iterable);
+}
+
/* The empty frozenset is a singleton */
static PyObject *emptyfrozenset = NULL;
@@ -1129,7 +1141,7 @@
static PyObject *
set_copy(PySetObject *so)
{
- return make_new_set(Py_TYPE(so), (PyObject *)so);
+ return make_new_set_basetype(Py_TYPE(so), (PyObject *)so);
}
static PyObject *
@@ -1225,7 +1237,7 @@
if ((PyObject *)so == other)
return set_copy(so);
- result = (PySetObject *)make_new_set(Py_TYPE(so), NULL);
+ result = (PySetObject *)make_new_set_basetype(Py_TYPE(so), NULL);
if (result == NULL)
return NULL;
@@ -1520,7 +1532,7 @@
return NULL;
}
- result = make_new_set(Py_TYPE(so), NULL);
+ result = make_new_set_basetype(Py_TYPE(so), NULL);
if (result == NULL)
return NULL;
@@ -1641,7 +1653,7 @@
Py_INCREF(other);
otherset = (PySetObject *)other;
} else {
- otherset = (PySetObject *)make_new_set(Py_TYPE(so), other);
+ otherset = (PySetObject *)make_new_set_basetype(Py_TYPE(so), other);
if (otherset == NULL)
return NULL;
}
@@ -1672,7 +1684,7 @@
PyObject *rv;
PySetObject *otherset;
- otherset = (PySetObject *)make_new_set(Py_TYPE(so), other);
+ otherset = (PySetObject *)make_new_set_basetype(Py_TYPE(so), other);
if (otherset == NULL)
return NULL;
rv = set_symmetric_difference_update(otherset, (PyObject *)so);