Allow admins to proactively block rooms (#11228)

Co-authored-by: Dirk Klimpel <5740567+dklimpel@users.noreply.github.com>
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

1 files changed, 17 insertions, 4 deletions

diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index 05c823d9ce..a2f4edebb8 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 import logging
 from http import HTTPStatus
-from typing import TYPE_CHECKING, List, Optional, Tuple
+from typing import TYPE_CHECKING, List, Optional, Tuple, cast
 from urllib import parse as urlparse
 
 from synapse.api.constants import EventTypes, JoinRules, Membership
@@ -239,9 +239,22 @@ class RoomRestServlet(RestServlet):
 
         # Purge room
         if purge:
-            await pagination_handler.purge_room(room_id, force=force_purge)
-
-        return 200, ret
+            try:
+                await pagination_handler.purge_room(room_id, force=force_purge)
+            except NotFoundError:
+                if block:
+                    # We can block unknown rooms with this endpoint, in which case
+                    # a failed purge is expected.
+                    pass
+                else:
+                    # But otherwise, we expect this purge to have succeeded.
+                    raise
+
+        # Cast safety: cast away the knowledge that this is a TypedDict.
+        # See https://github.com/python/mypy/issues/4976#issuecomment-579883622
+        # for some discussion on why this is necessary. Either way,
+        # `ret` is an opaque dictionary blob as far as the rest of the app cares.
+        return 200, cast(JsonDict, ret)
 
 
 class RoomMembersRestServlet(RestServlet):