reraise exceptions more carefully

We need to be careful (under python 2, at least) that when we reraise an
exception after doing some error handling, we actually reraise the original
exception rather than anything that might have been raised (and handled) during
the error handling.

1 files changed, 14 insertions, 7 deletions

diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 21628a8540..8e2e44bdcd 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -13,6 +13,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import logging
+import simplejson
+import sys
+
+from canonicaljson import encode_canonical_json
+import six
 from twisted.internet import defer, reactor
 from twisted.python.failure import Failure
 
@@ -34,11 +40,6 @@ from synapse.replication.http.send_event import send_event_to_master
 
 from ._base import BaseHandler
 
-from canonicaljson import encode_canonical_json
-
-import logging
-import simplejson
-
 logger = logging.getLogger(__name__)
 
 
@@ -729,8 +730,14 @@ class EventCreationHandler(object):
         except:  # noqa: E722, as we reraise the exception this is fine.
             # Ensure that we actually remove the entries in the push actions
             # staging area, if we calculated them.
-            preserve_fn(self.store.remove_push_actions_from_staging)(event.event_id)
-            raise
+            tp, value, tb = sys.exc_info()
+
+            run_in_background(
+                self.store.remove_push_actions_from_staging,
+                event.event_id,
+            )
+
+            six.reraise(tp, value, tb)
 
     @defer.inlineCallbacks
     def persist_and_notify_client_event(