Merge pull request #6790 from matrix-org/rav/msc2260.1

MSC2260: change the default power level for m.room.aliases events

2 files changed, 32 insertions, 15 deletions

diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index a07d2f1a17..8c5980cb0c 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -151,7 +151,12 @@ class DirectoryHandler(BaseHandler):
 
         yield self._create_association(room_alias, room_id, servers, creator=user_id)
         if send_event:
-            yield self.send_room_alias_update_event(requester, room_id)
+            try:
+                yield self.send_room_alias_update_event(requester, room_id)
+            except AuthError as e:
+                # sending the aliases event may fail due to the user not having
+                # permission in the room; this is permitted.
+                logger.info("Skipping updating aliases event due to auth error %s", e)
 
     @defer.inlineCallbacks
     def delete_association(self, requester, room_alias, send_event=True):
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index a9490782b7..a95b45d791 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -30,6 +30,7 @@ from twisted.internet import defer
 from synapse.api.constants import EventTypes, JoinRules, RoomCreationPreset
 from synapse.api.errors import AuthError, Codes, NotFoundError, StoreError, SynapseError
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion
+from synapse.events.utils import copy_power_levels_contents
 from synapse.http.endpoint import parse_and_validate_server_name
 from synapse.storage.state import StateFilter
 from synapse.types import (
@@ -286,7 +287,16 @@ class RoomCreationHandler(BaseHandler):
             except AuthError as e:
                 logger.warning("Unable to update PLs in old room: %s", e)
 
-        logger.info("Setting correct PLs in new room to %s", old_room_pl_state.content)
+        new_pl_content = copy_power_levels_contents(old_room_pl_state.content)
+
+        # pre-msc2260 rooms may not have the right setting for aliases. If no other
+        # value is set, set it now.
+        events_default = new_pl_content.get("events_default", 0)
+        new_pl_content.setdefault("events", {}).setdefault(
+            EventTypes.Aliases, events_default
+        )
+
+        logger.info("Setting correct PLs in new room to %s", new_pl_content)
         yield self.event_creation_handler.create_and_send_nonmember_event(
             requester,
             {
@@ -294,7 +304,7 @@ class RoomCreationHandler(BaseHandler):
                 "state_key": "",
                 "room_id": new_room_id,
                 "sender": requester.user.to_string(),
-                "content": old_room_pl_state.content,
+                "content": new_pl_content,
             },
             ratelimit=False,
         )
@@ -367,6 +377,15 @@ class RoomCreationHandler(BaseHandler):
             if old_event:
                 initial_state[k] = old_event.content
 
+        # deep-copy the power-levels event before we start modifying it
+        # note that if frozen_dicts are enabled, `power_levels` will be a frozen
+        # dict so we can't just copy.deepcopy it.
+        initial_state[
+            (EventTypes.PowerLevels, "")
+        ] = power_levels = copy_power_levels_contents(
+            initial_state[(EventTypes.PowerLevels, "")]
+        )
+
         # Resolve the minimum power level required to send any state event
         # We will give the upgrading user this power level temporarily (if necessary) such that
         # they are able to copy all of the state events over, then revert them back to their
@@ -375,8 +394,6 @@ class RoomCreationHandler(BaseHandler):
         # Copy over user power levels now as this will not be possible with >100PL users once
         # the room has been created
 
-        power_levels = initial_state[(EventTypes.PowerLevels, "")]
-
         # Calculate the minimum power level needed to clone the room
         event_power_levels = power_levels.get("events", {})
         state_default = power_levels.get("state_default", 0)
@@ -386,16 +403,7 @@ class RoomCreationHandler(BaseHandler):
         # Raise the requester's power level in the new room if necessary
         current_power_level = power_levels["users"][user_id]
         if current_power_level < needed_power_level:
-            # make sure we copy the event content rather than overwriting it.
-            # note that if frozen_dicts are enabled, `power_levels` will be a frozen
-            # dict so we can't just copy.deepcopy it.
-
-            new_power_levels = {k: v for k, v in power_levels.items() if k != "users"}
-            new_power_levels["users"] = {
-                k: v for k, v in power_levels.get("users", {}).items() if k != user_id
-            }
-            new_power_levels["users"][user_id] = needed_power_level
-            initial_state[(EventTypes.PowerLevels, "")] = new_power_levels
+            power_levels["users"][user_id] = needed_power_level
 
         yield self._send_events_for_new_room(
             requester,
@@ -813,6 +821,10 @@ class RoomCreationHandler(BaseHandler):
                     EventTypes.RoomHistoryVisibility: 100,
                     EventTypes.CanonicalAlias: 50,
                     EventTypes.RoomAvatar: 50,
+                    # MSC2260: Allow everybody to send alias events by default
+                    # This will be reudundant on pre-MSC2260 rooms, since the
+                    # aliases event is special-cased.
+                    EventTypes.Aliases: 0,
                 },
                 "events_default": 0,
                 "state_default": 50,