Fix a couple of bugs in the transaction and keyring code

synapse/crypto/keyring.py

@@ -275,7 +275,8 @@ class Keyring(object):
                     for server_name, groups in missing_groups.items()
                 }
 
-            for group in missing_groups.values():
+            for groups in missing_groups.values():
+                for group in groups:
                     group_id_to_deferred[group.group_id].errback(SynapseError(
                         401,
                         "No key for %s with id %s" % (

synapse/storage/transactions.py

@@ -24,6 +24,7 @@ from collections import namedtuple
 
 import itertools
 import logging
+import ujson as json
 
 logger = logging.getLogger(__name__)
 
@@ -101,7 +102,7 @@ class TransactionStore(SQLBaseStore):
         )
 
         if result and result["response_code"]:
-            return result["response_code"], result["response_json"]
+            return result["response_code"], json.loads(str(result["response_json"]))
         else:
             return None