Fix _cbson DBPointer decoding in py3 PYTHON-586

bson/__init__.py

@@ -270,8 +270,8 @@ def _get_regex(data, position, as_class, tz_aware, uuid_subtype):
 
 
 def _get_ref(data, position, as_class, tz_aware, uuid_subtype):
-    position += 4
-    collection, position = _get_c_string(data, position)
+    collection, position = _get_string(data, position,
+                                       as_class, tz_aware, uuid_subtype)
     oid, position = _get_oid(data, position)
     return DBRef(collection, oid), position
 

bson/_cbsonmodule.c

@@ -1883,7 +1883,11 @@ static PyObject* get_value(PyObject* self, const char* buffer, unsigned* positio
             *position += coll_length;
 
             if ((objectid_type = _get_object(state->ObjectId, "bson.objectid", "ObjectId"))) {
+#if PY_MAJOR_VERSION >= 3
+                id = PyObject_CallFunction(objectid_type, "y#", buffer + *position, 12);
+#else
                 id = PyObject_CallFunction(objectid_type, "s#", buffer + *position, 12);
+#endif
                 Py_DECREF(objectid_type);
             }
             if (!id) {

test/test_bson.py

@@ -220,6 +220,19 @@ class TestBSON(unittest.TestCase):
         qcheck.check_unittest(self, encode_then_decode,
                               qcheck.gen_mongo_dict(3))
 
+    def test_dbpointer(self):
+        # *Note* - DBPointer and DBRef are *not* the same thing. DBPointer
+        # is a deprecated BSON type. DBRef is a convention that does not
+        # exist in the BSON spec, meant to replace DBPointer. PyMongo does
+        # not support creation of the DBPointer type, but will decode
+        # DBPointer to DBRef.
+
+        bs = b("\x18\x00\x00\x00\x0c\x00\x01\x00\x00"
+               "\x00\x00RY\xb5j\xfa[\xd8A\xd6X]\x99\x00")
+
+        self.assertEqual({'': DBRef('', ObjectId('5259b56afa5bd841d6585d99'))},
+                         bson.BSON(bs).decode())
+
     def test_bad_dbref(self):
         ref_only = {'ref': {'$ref': 'collection'}}
         id_only = {'ref': {'$id': ObjectId()}}