diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py index 1a8ae1cd42356e..71f72cb2557670 100644 --- a/Lib/test/test_dict.py +++ b/Lib/test/test_dict.py @@ -1815,6 +1815,16 @@ class FrozenDictSubclass2(frozendict): self.assertEqual(fd, frozendict(a=None, b=None, c=None)) self.assertEqual(type(fd), FrozenDictSubclass2) + # Dict subclass which overrides the constructor + class DictSubclass(dict): + def __new__(self): + return created + + fd = DictSubclass.fromkeys("abc") + self.assertEqual(fd, frozendict(x=1, a=None, b=None, c=None)) + self.assertEqual(type(fd), DictSubclass) + self.assertEqual(created, frozendict(x=1)) + if __name__ == "__main__": unittest.main() diff --git a/Objects/dictobject.c b/Objects/dictobject.c index 8d3c34f87e2afe..af3fcca7455470 100644 --- a/Objects/dictobject.c +++ b/Objects/dictobject.c @@ -138,6 +138,7 @@ As a consequence of this, split keys have a maximum size of 16. // Forward declarations static PyObject* frozendict_new(PyTypeObject *type, PyObject *args, PyObject *kwds); +static PyObject* dict_new(PyTypeObject *type, PyObject *args, PyObject *kwds); static int dict_merge(PyObject *a, PyObject *b, int override); @@ -3305,15 +3306,18 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value) return NULL; } - // If cls is a frozendict subclass with overridden constructor, + // If cls is a dict or frozendict subclass with overridden constructor, // copy the frozendict. PyTypeObject *cls_type = _PyType_CAST(cls); - if (PyFrozenDict_Check(d) - && PyObject_IsSubclass(cls, (PyObject*)&PyFrozenDict_Type) - && cls_type->tp_new != frozendict_new) - { + if (PyFrozenDict_Check(d) && cls_type->tp_new != frozendict_new) { // Subclass-friendly copy - PyObject *copy = frozendict_new(cls_type, NULL, NULL); + PyObject *copy; + if (PyObject_IsSubclass(cls, (PyObject*)&PyFrozenDict_Type)) { + copy = frozendict_new(cls_type, NULL, NULL); + } + else { + copy = dict_new(cls_type, NULL, NULL); + } if (copy == NULL) { Py_DECREF(d); return NULL;