Enforce that / lists passed as arguments must be empty.

gcloud/datastore/connection.py

@@ -219,6 +219,12 @@ def lookup(self, dataset_id, key_pbs, missing=None, deferred=None):
                   If multiple keys were provided and no results matched,
                   this will return an empty list.
         """
+        if missing is not None and missing != []:
+            raise ValueError('missing must be None or an empty list')
+
+        if deferred is not None and deferred != []:
+            raise ValueError('deferred must be None or an empty list')
+
         lookup_request = datastore_pb.LookupRequest()
 
         single_key = isinstance(key_pbs, datastore_pb.Key)

gcloud/datastore/test_connection.py

@@ -329,6 +329,16 @@ def test_lookup_multiple_keys_w_missing(self):
         self.assertEqual(keys[0], key_pb1)
         self.assertEqual(keys[1], key_pb2)
 
+    def test_lookup_multiple_keys_w_missing_non_empty(self):
+        from gcloud.datastore.key import Key
+        DATASET_ID = 'DATASET'
+        key_pb1 = Key(path=[{'kind': 'Kind', 'id': 1234}]).to_protobuf()
+        key_pb2 = Key(path=[{'kind': 'Kind', 'id': 2345}]).to_protobuf()
+        conn = self._makeOne()
+        missing = ['this', 'list', 'is', 'not', 'empty']
+        self.assertRaises(ValueError,
+            conn.lookup, DATASET_ID, [key_pb1, key_pb2], missing=missing)
+
     def test_lookup_multiple_keys_w_deferred(self):
         from gcloud.datastore.connection import datastore_pb
         from gcloud.datastore.key import Key
@@ -368,6 +378,16 @@ def test_lookup_multiple_keys_w_deferred(self):
         self.assertEqual(keys[0], key_pb1)
         self.assertEqual(keys[1], key_pb2)
 
+    def test_lookup_multiple_keys_w_deferred_non_empty(self):
+        from gcloud.datastore.key import Key
+        DATASET_ID = 'DATASET'
+        key_pb1 = Key(path=[{'kind': 'Kind', 'id': 1234}]).to_protobuf()
+        key_pb2 = Key(path=[{'kind': 'Kind', 'id': 2345}]).to_protobuf()
+        conn = self._makeOne()
+        deferred = ['this', 'list', 'is', 'not', 'empty']
+        self.assertRaises(ValueError,
+            conn.lookup, DATASET_ID, [key_pb1, key_pb2], deferred=deferred)
+
     def test_lookup_multiple_keys_w_deferred_from_backend_but_not_passed(self):
         from gcloud.datastore.connection import datastore_pb
         from gcloud.datastore.key import Key