diff options
Diffstat (limited to 'Python/bltinmodule.c')
| -rw-r--r-- | Python/bltinmodule.c | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c index 6258167..9c50b88 100644 --- a/Python/bltinmodule.c +++ b/Python/bltinmodule.c @@ -35,9 +35,10 @@ int Py_HasFileSystemDefaultEncoding = 1; static PyObject * builtin___build_class__(PyObject *self, PyObject *args, PyObject *kwds) { - PyObject *func, *name, *bases, *mkw, *meta, *prep, *ns, *cell; + PyObject *func, *name, *bases, *mkw, *meta, *winner, *prep, *ns, *cell; PyObject *cls = NULL; Py_ssize_t nargs, nbases; + int isclass; assert(args != NULL); if (!PyTuple_Check(args)) { @@ -82,17 +83,42 @@ builtin___build_class__(PyObject *self, PyObject *args, PyObject *kwds) Py_DECREF(bases); return NULL; } + /* metaclass is explicitly given, check if it's indeed a class */ + isclass = PyType_Check(meta); } } if (meta == NULL) { - if (PyTuple_GET_SIZE(bases) == 0) + /* if there are no bases, use type: */ + if (PyTuple_GET_SIZE(bases) == 0) { meta = (PyObject *) (&PyType_Type); + } + /* else get the type of the first base */ else { PyObject *base0 = PyTuple_GET_ITEM(bases, 0); meta = (PyObject *) (base0->ob_type); } Py_INCREF(meta); + isclass = 1; /* meta is really a class */ + } + if (isclass) { + /* meta is really a class, so check for a more derived + metaclass, or possible metaclass conflicts: */ + winner = (PyObject *)_PyType_CalculateMetaclass((PyTypeObject *)meta, + bases); + if (winner == NULL) { + Py_DECREF(meta); + Py_XDECREF(mkw); + Py_DECREF(bases); + return NULL; + } + if (winner != meta) { + Py_DECREF(meta); + meta = winner; + Py_INCREF(meta); + } } + /* else: meta is not a class, so we cannot do the metaclass + calculation, so we will use the explicitly given object as it is */ prep = PyObject_GetAttrString(meta, "__prepare__"); if (prep == NULL) { if (PyErr_ExceptionMatches(PyExc_AttributeError)) { |