From 5e8519ea3b8bb9482f3b35adc04e5e4b69d14976 Mon Sep 17 00:00:00 2001
From: Patrick Cloke <patrickc@matrix.org>
Date: Tue, 14 Dec 2021 08:57:12 -0500
Subject: [PATCH 1/2] Convert EventStreamResult to attrs.

---
 synapse/handlers/events.py |  7 ++++---
 synapse/notifier.py        | 25 +++++++++++++++++++------
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index 32b0254c5f08..afed80ba14c0 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -79,13 +79,14 @@ async def get_stream(
                 # thundering herds on restart.
                 timeout = random.randint(int(timeout * 0.9), int(timeout * 1.1))
 
-            events, tokens = await self.notifier.get_events_for(
+            stream_result = await self.notifier.get_events_for(
                 auth_user,
                 pagin_config,
                 timeout,
                 is_guest=is_guest,
                 explicit_room_id=room_id,
             )
+            events = stream_result.events
 
             time_now = self.clock.time_msec()
 
@@ -128,8 +129,8 @@ async def get_stream(
 
             chunk = {
                 "chunk": chunks,
-                "start": await tokens[0].to_string(self.store),
-                "end": await tokens[1].to_string(self.store),
+                "start": await stream_result.start_token.to_string(self.store),
+                "end": await stream_result.end_token.to_string(self.store),
             }
 
             return chunk
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 60e5409895e6..bbabdb05875c 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 
 import logging
-from collections import namedtuple
 from typing import (
     Awaitable,
     Callable,
@@ -44,7 +43,13 @@
 from synapse.logging.utils import log_function
 from synapse.metrics import LaterGauge
 from synapse.streams.config import PaginationConfig
-from synapse.types import PersistedEventPosition, RoomStreamToken, StreamToken, UserID
+from synapse.types import (
+    JsonDict,
+    PersistedEventPosition,
+    RoomStreamToken,
+    StreamToken,
+    UserID,
+)
 from synapse.util.async_helpers import ObservableDeferred, timeout_deferred
 from synapse.util.metrics import Measure
 from synapse.visibility import filter_events_for_client
@@ -178,7 +183,12 @@ def new_listener(self, token: StreamToken) -> _NotificationListener:
             return _NotificationListener(self.notify_deferred.observe())
 
 
-class EventStreamResult(namedtuple("EventStreamResult", ("events", "tokens"))):
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class EventStreamResult:
+    events: List[Union[JsonDict, EventBase]]
+    start_token: StreamToken
+    end_token: StreamToken
+
     def __bool__(self):
         return bool(self.events)
 
@@ -582,9 +592,12 @@ async def check_for_updates(
             before_token: StreamToken, after_token: StreamToken
         ) -> EventStreamResult:
             if after_token == before_token:
-                return EventStreamResult([], (from_token, from_token))
+                return EventStreamResult([], from_token, from_token)
 
-            events: List[EventBase] = []
+            # The events fetched from each source are a JsonDict, EventBase, or
+            # UserPresenceState, but see below for UserPresenceState being
+            # converted to JsonDict.
+            events: List[Union[JsonDict, EventBase]] = []
             end_token = from_token
 
             for name, source in self.event_sources.sources.get_sources():
@@ -623,7 +636,7 @@ async def check_for_updates(
                 events.extend(new_events)
                 end_token = end_token.copy_and_replace(keyname, new_key)
 
-            return EventStreamResult(events, (from_token, end_token))
+            return EventStreamResult(events, from_token, end_token)
 
         user_id_for_stream = user.to_string()
         if is_peeking:

From da6a0e5782939fd009612634d18e6852071887fc Mon Sep 17 00:00:00 2001
From: Patrick Cloke <patrickc@matrix.org>
Date: Tue, 14 Dec 2021 09:55:26 -0500
Subject: [PATCH 2/2] Newsfragment

---
 changelog.d/11574.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/11574.misc

diff --git a/changelog.d/11574.misc b/changelog.d/11574.misc
new file mode 100644
index 000000000000..2b090a3780d0
--- /dev/null
+++ b/changelog.d/11574.misc
@@ -0,0 +1 @@
+Convert `EventStreamResult` from a `namedtuple` to `attrs` to improve type hints.