Do not recurse into non-spaces in the spaces summary. (#10256)

Previously m.child.room events in non-space rooms would be
treated as part of the room graph, but this is no longer
supported.

2 files changed, 15 insertions, 2 deletions

diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 414e4c019a..8363c2bb0f 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -201,6 +201,12 @@ class EventContentFields:
     )
 
 
+class RoomTypes:
+    """Understood values of the room_type field of m.room.create events."""
+
+    SPACE = "m.space"
+
+
 class RoomEncryptionAlgorithms:
     MEGOLM_V1_AES_SHA2 = "m.megolm.v1.aes-sha2"
     DEFAULT = MEGOLM_V1_AES_SHA2
diff --git a/synapse/handlers/space_summary.py b/synapse/handlers/space_summary.py
index 17fc47ce16..266f369883 100644
--- a/synapse/handlers/space_summary.py
+++ b/synapse/handlers/space_summary.py
@@ -25,6 +25,7 @@ from synapse.api.constants import (
     EventTypes,
     HistoryVisibility,
     Membership,
+    RoomTypes,
 )
 from synapse.events import EventBase
 from synapse.events.utils import format_event_for_client_v2
@@ -318,7 +319,8 @@ class SpaceSummaryHandler:
 
         Returns:
             A tuple of:
-                An iterable of a single value of the room.
+                The room information, if the room should be returned to the
+                user. None, otherwise.
 
                 An iterable of the sorted children events. This may be limited
                 to a maximum size or may include all children.
@@ -328,7 +330,11 @@ class SpaceSummaryHandler:
 
         room_entry = await self._build_room_entry(room_id)
 
-        # look for child rooms/spaces.
+        # If the room is not a space, return just the room information.
+        if room_entry.get("room_type") != RoomTypes.SPACE:
+            return room_entry, ()
+
+        # Otherwise, look for child rooms/spaces.
         child_events = await self._get_child_events(room_id)
 
         if suggested_only:
@@ -348,6 +354,7 @@ class SpaceSummaryHandler:
                     event_format=format_event_for_client_v2,
                 )
             )
+
         return room_entry, events_result
 
     async def _summarize_remote_room(