3 files changed, 27 insertions, 8 deletions
diff --git a/synapse/storage/event_federation.py b/synapse/storage/event_federation.py
index 8bd35df119..24345b20a6 100644
--- a/synapse/storage/event_federation.py
+++ b/synapse/storage/event_federation.py
@@ -343,6 +343,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,
                 table="events",
                 keyvalues={
                     "event_id": event_id,
+                    "room_id": room_id,
                 },
                 retcol="depth",
                 allow_none=True,
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 61223da1a5..e8e5a0fe44 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -241,12 +241,18 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
 
         self._state_resolution_handler = hs.get_state_resolution_handler()
 
+    @defer.inlineCallbacks
     def persist_events(self, events_and_contexts, backfilled=False):
         """
         Write events to the database
         Args:
             events_and_contexts: list of tuples of (event, context)
-            backfilled: ?
+            backfilled (bool): Whether the results are retrieved from federation
+                via backfill or not. Used to determine if they're "new" events
+                which might update the current state etc.
+
+        Returns:
+            Deferred[int]: the stream ordering of the latest persisted event
         """
         partitioned = {}
         for event, ctx in events_and_contexts:
@@ -263,10 +269,14 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
         for room_id in partitioned:
             self._maybe_start_persisting(room_id)
 
-        return make_deferred_yieldable(
+        yield make_deferred_yieldable(
             defer.gatherResults(deferreds, consumeErrors=True)
         )
 
+        max_persisted_id = yield self._stream_id_gen.get_current_token()
+
+        defer.returnValue(max_persisted_id)
+
     @defer.inlineCallbacks
     @log_function
     def persist_event(self, event, context, backfilled=False):
diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py
index f28239a808..9b4cfeb899 100644
--- a/synapse/storage/events_worker.py
+++ b/synapse/storage/events_worker.py
@@ -19,7 +19,7 @@ from canonicaljson import json
 
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError
+from synapse.api.errors import NotFoundError
 # these are only included to make the type annotations work
 from synapse.events import EventBase  # noqa: F401
 from synapse.events import FrozenEvent
@@ -77,7 +77,7 @@ class EventsWorkerStore(SQLBaseStore):
     @defer.inlineCallbacks
     def get_event(self, event_id, check_redacted=True,
                   get_prev_content=False, allow_rejected=False,
-                  allow_none=False):
+                  allow_none=False, check_room_id=None):
         """Get an event from the database by event_id.
 
         Args:
@@ -88,7 +88,9 @@ class EventsWorkerStore(SQLBaseStore):
                 include the previous states content in the unsigned field.
             allow_rejected (bool): If True return rejected events.
             allow_none (bool): If True, return None if no event found, if
-                False throw an exception.
+                False throw a NotFoundError
+            check_room_id (str|None): if not None, check the room of the found event.
+                If there is a mismatch, behave as per allow_none.
 
         Returns:
             Deferred : A FrozenEvent.
@@ -100,10 +102,16 @@ class EventsWorkerStore(SQLBaseStore):
             allow_rejected=allow_rejected,
         )
 
-        if not events and not allow_none:
-            raise SynapseError(404, "Could not find event %s" % (event_id,))
+        event = events[0] if events else None
 
-        defer.returnValue(events[0] if events else None)
+        if event is not None and check_room_id is not None:
+            if event.room_id != check_room_id:
+                event = None
+
+        if event is None and not allow_none:
+            raise NotFoundError("Could not find event %s" % (event_id,))
+
+        defer.returnValue(event)
 
     @defer.inlineCallbacks
     def get_events(self, event_ids, check_redacted=True,