Fix Python 3.4 cpp implementation

Fixes the ScalarMapContainer/MessageMapContainer implementations on
Python 3.4, by dynamically allocating their PyTypeObjects using
PyType_FromSpecWithBases, instead of statically allocating them. This is
necessary because Python 3.4+ disallows statically allocating a class
with a dynamically allocated parent.

Signed-off-by: Dan O'Reilly <oreilldf@gmail.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
index 62c7c478..04544cad 100644
--- a/python/google/protobuf/pyext/message.cc
+++ b/python/google/protobuf/pyext/message.cc
@@ -2863,6 +2863,14 @@ bool InitProto2MessageModule(PyObject *m) {
     }
 
     Py_INCREF(mutable_mapping);
+#if PY_MAJOR_VERSION >= 3
+    PyObject* bases = PyTuple_New(1);
+    PyTuple_SET_ITEM(bases, 0, mutable_mapping.get());
+
+    ScalarMapContainer_Type = 
+        PyType_FromSpecWithBases(&ScalarMapContainer_Type_spec, bases);
+    PyModule_AddObject(m, "ScalarMapContainer", ScalarMapContainer_Type);
+#else
     ScalarMapContainer_Type.tp_base =
         reinterpret_cast<PyTypeObject*>(mutable_mapping.get());
 
@@ -2872,6 +2880,7 @@ bool InitProto2MessageModule(PyObject *m) {
 
     PyModule_AddObject(m, "ScalarMapContainer",
                        reinterpret_cast<PyObject*>(&ScalarMapContainer_Type));
+#endif
 
     if (PyType_Ready(&ScalarMapIterator_Type) < 0) {
       return false;
@@ -2880,6 +2889,12 @@ bool InitProto2MessageModule(PyObject *m) {
     PyModule_AddObject(m, "ScalarMapIterator",
                        reinterpret_cast<PyObject*>(&ScalarMapIterator_Type));
 
+
+#if PY_MAJOR_VERSION >= 3
+    MessageMapContainer_Type = 
+        PyType_FromSpecWithBases(&MessageMapContainer_Type_spec, bases);
+    PyModule_AddObject(m, "MessageMapContainer", MessageMapContainer_Type);
+#else
     Py_INCREF(mutable_mapping);
     MessageMapContainer_Type.tp_base =
         reinterpret_cast<PyTypeObject*>(mutable_mapping.get());
@@ -2890,6 +2905,7 @@ bool InitProto2MessageModule(PyObject *m) {
 
     PyModule_AddObject(m, "MessageMapContainer",
                        reinterpret_cast<PyObject*>(&MessageMapContainer_Type));
+#endif
 
     if (PyType_Ready(&MessageMapIterator_Type) < 0) {
       return false;