From 7709a99e6ffe690abe9dd6999bf09f6f1ad7d32f Mon Sep 17 00:00:00 2001
From: Mathieu Velten <mathieuv@matrix.org>
Date: Mon, 22 May 2023 18:32:32 +0200
Subject: [PATCH] Fix order

---
 synapse/handlers/room_list.py                 |  1 +
 .../callbacks/public_rooms_callbacks.py       |  4 +-
 tests/module_api/test_fetch_public_rooms.py   | 68 +++++++++++--------
 3 files changed, 41 insertions(+), 32 deletions(-)

diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py
index f759c2888b..6c821669b0 100644
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@@ -189,6 +189,7 @@ class RoomListHandler:
                 if batch_token
                 else None,
             )
+            module_public_rooms.reverse()
 
             # Insert the module's reported public rooms into the list
             for new_room in module_public_rooms:
diff --git a/synapse/module_api/callbacks/public_rooms_callbacks.py b/synapse/module_api/callbacks/public_rooms_callbacks.py
index 88f996b684..9934f70c27 100644
--- a/synapse/module_api/callbacks/public_rooms_callbacks.py
+++ b/synapse/module_api/callbacks/public_rooms_callbacks.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import logging
-from typing import Awaitable, Callable, Iterable, List, Optional, Tuple
+from typing import Awaitable, Callable, List, Optional, Tuple
 
 from synapse.types import PublicRoom
 
@@ -23,7 +23,7 @@ logger = logging.getLogger(__name__)
 # Types for callbacks to be registered via the module api
 FETCH_PUBLIC_ROOMS_CALLBACK = Callable[
     [bool, Optional[int], Optional[Tuple[int, str]]],
-    Awaitable[Iterable[PublicRoom]],
+    Awaitable[List[PublicRoom]],
 ]
 
 
diff --git a/tests/module_api/test_fetch_public_rooms.py b/tests/module_api/test_fetch_public_rooms.py
index dacc05ac5f..bee351f29e 100644
--- a/tests/module_api/test_fetch_public_rooms.py
+++ b/tests/module_api/test_fetch_public_rooms.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from http import HTTPStatus
-from typing import Iterable, Optional, Tuple
+from typing import List, Optional, Tuple
 
 from twisted.test.proto_helpers import MemoryReactor
 
@@ -47,38 +47,46 @@ class FetchPublicRoomsTestCase(HomeserverTestCase):
 
         async def cb(
             forwards: bool, limit: Optional[int], bounds: Optional[Tuple[int, str]]
-        ) -> Iterable[PublicRoom]:
-            room1 = PublicRoom(
-                room_id="!test1:test",
-                num_joined_members=1,
-                world_readable=True,
-                guest_can_join=False,
-            )
-            room3 = PublicRoom(
-                room_id="!test3:test",
-                num_joined_members=3,
-                world_readable=True,
-                guest_can_join=False,
-            )
-            room3_2 = PublicRoom(
-                room_id="!test3_2:test",
-                num_joined_members=3,
-                world_readable=True,
-                guest_can_join=False,
-            )
-            rooms = [room3_2, room3, room1]
-            if not forwards:
-                rooms.reverse()
+        ) -> List[PublicRoom]:
+            rooms_db = [
+                PublicRoom(
+                    room_id="!test1:test",
+                    num_joined_members=1,
+                    world_readable=True,
+                    guest_can_join=False,
+                ),
+                PublicRoom(
+                    room_id="!test3:test",
+                    num_joined_members=3,
+                    world_readable=True,
+                    guest_can_join=False,
+                ),
+                PublicRoom(
+                    room_id="!test3_2:test",
+                    num_joined_members=3,
+                    world_readable=True,
+                    guest_can_join=False,
+                ),
+            ]
+
+            result = []
+            if limit is not None and bounds is not None:
+                (last_joined_members, last_room_id) = bounds
+                for r in rooms_db:
+                    if r.num_joined_members <= last_joined_members:
+                        if r.room_id == last_room_id:
+                            break
+                        result.append(r)
+            else:
+                result = rooms_db
+
+            if forwards:
+                result.reverse()
 
             if limit is not None:
-                if bounds is None:
-                    return rooms[:limit]
+                result = result[:limit]
 
-                (last_joined_members, last_room_id) = bounds
-                if last_joined_members < 3 or last_room_id == room3_2.room_id:
-                    return [room3, room1]
-
-            return [room3_2, room3, room1]
+            return result
 
         self._module_api.register_public_rooms_callbacks(fetch_public_rooms=cb)