add default_power_level_content_override config option.

changelog.d/12618.feature

@@ -1 +1 @@
-Add default_power_level_content_override config option.
+Add a `default_power_level_content_override` config option to set default room power levels.

docs/sample_config.yaml

@@ -2458,18 +2458,40 @@ push:
 # Override the default power levels for rooms created on this server, per
 # room creation preset.
 #
+# The appropriate dictionary for the room preset will be applied on top
+# of the existing power levels content.
+#
 # Useful if you know that your users need special permissions in rooms
 # that they create (e.g. to send particular types of state events without
 # needing an elevated power level).  This takes the same shape as the
 # `power_level_content_override` parameter in the /createRoom API, but
 # is applied before that parameter.
 #
-# This is something of a workaround in the absence of MSC3779 or MSC3761.
+# Valid keys are some or all of `private_chat`, `trusted_private_chat`
+# and `public_chat`. Inside each of those should be any of the
+# properties allowed in `power_level_content_override` in the
+# /createRoom API. If any property is missing, its default value will
+# continue to be use. If any property is present, it will overwrite
+# the existing default completely (so if the `events` property exists,
+# the default event power levels will be ignored).
 #
 #default_power_level_content_override:
-#   private_chat: { "events": { "com.example.foo" : 0 } }
-#   trusted_private_chat: null
-#   public_chat: null
+#    private_chat: {
+#        "events": {
+#            "com.example.myeventtype" : 0,
+#            "m.room.avatar": 50,
+#            "m.room.canonical_alias": 50,
+#            "m.room.encryption": 100,
+#            "m.room.history_visibility": 100,
+#            "m.room.name": 50,
+#            "m.room.power_levels": 100,
+#            "m.room.server_acl": 100,
+#            "m.room.tombstone": 100
+#        },
+#        "events_default": 1
+#    }
+#    trusted_private_chat: null
+#    public_chat: null
 
 
 # Uncomment to allow non-server-admin users to create groups on this server

synapse/config/room.py

@@ -100,16 +100,38 @@ def generate_config_section(self, **kwargs: Any) -> str:
         # Override the default power levels for rooms created on this server, per
         # room creation preset.
         #
+        # The appropriate dictionary for the room preset will be applied on top
+        # of the existing power levels content.
+        #
         # Useful if you know that your users need special permissions in rooms
         # that they create (e.g. to send particular types of state events without
         # needing an elevated power level).  This takes the same shape as the
         # `power_level_content_override` parameter in the /createRoom API, but
         # is applied before that parameter.
         #
-        # This is something of a workaround in the absence of MSC3779 or MSC3761.
+        # Valid keys are some or all of `private_chat`, `trusted_private_chat`
+        # and `public_chat`. Inside each of those should be any of the
+        # properties allowed in `power_level_content_override` in the
+        # /createRoom API. If any property is missing, its default value will
+        # continue to be use. If any property is present, it will overwrite
+        # the existing default completely (so if the `events` property exists,
+        # the default event power levels will be ignored).
         #
         #default_power_level_content_override:
-        #   private_chat: { "events": { "com.example.foo" : 0 } }
-        #   trusted_private_chat: null
-        #   public_chat: null
+        #    private_chat: {
+        #        "events": {
+        #            "com.example.myeventtype" : 0,
+        #            "m.room.avatar": 50,
+        #            "m.room.canonical_alias": 50,
+        #            "m.room.encryption": 100,
+        #            "m.room.history_visibility": 100,
+        #            "m.room.name": 50,
+        #            "m.room.power_levels": 100,
+        #            "m.room.server_acl": 100,
+        #            "m.room.tombstone": 100
+        #        },
+        #        "events_default": 1
+        #    }
+        #    trusted_private_chat: null
+        #    public_chat: null
         """

synapse/handlers/room.py

@@ -149,6 +149,10 @@ def __init__(self, hs: "HomeServer"):
             )
             preset_config["encrypted"] = encrypted
 
+        self._default_power_level_content_override = (
+            self.config.room.default_power_level_content_override
+        )
+
         self._replication = hs.get_replication_data_handler()
 
         # linearizer to stop two upgrades happening at once
@@ -1046,15 +1050,12 @@ async def send(etype: str, content: JsonDict, **kwargs: Any) -> int:
 
             # If the server config contains default_power_level_content_override,
             # and that contains information for this room preset, apply it.
-            default_power_level_content_override = (
-                self.config.room.default_power_level_content_override
-            )
             if (
-                default_power_level_content_override
-                and default_power_level_content_override.get(preset_config)
+                self._default_power_level_content_override
+                and self._default_power_level_content_override.get(preset_config)
             ):
                 power_level_content.update(
-                    default_power_level_content_override.get(preset_config)
+                    self._default_power_level_content_override.get(preset_config)
                 )
 
             # Finally, if the user supplied specific permissions for this room,

tests/rest/client/test_rooms.py

@@ -1136,33 +1136,6 @@ def power_levels(self, room_id: str) -> Dict[str, Any]:
             room_id, "m.room.power_levels", self.admin_access_token
         )
 
-    def test_default_power_levels_without_override(self) -> None:
-        room_id = self.helper.create_room_as(self.user_id)
-        self.assertEqual(
-            {
-                "ban": 50,
-                "events": {
-                    "m.room.avatar": 50,
-                    "m.room.canonical_alias": 50,
-                    "m.room.encryption": 100,
-                    "m.room.history_visibility": 100,
-                    "m.room.name": 50,
-                    "m.room.power_levels": 100,
-                    "m.room.server_acl": 100,
-                    "m.room.tombstone": 100,
-                },
-                "events_default": 0,
-                "historical": 100,
-                "invite": 50,
-                "kick": 50,
-                "redact": 50,
-                "state_default": 50,
-                "users": {"@sid1:red": 100},
-                "users_default": 0,
-            },
-            self.power_levels(room_id),
-        )
-
     def test_default_power_levels_with_room_override(self) -> None:
         """
         Create a room, providing power level overrides.
@@ -1181,20 +1154,9 @@ def test_default_power_levels_with_room_override(self) -> None:
         )
         self.assertEqual(
             {
-                "ban": 50,
-                "events": {
-                    "custom.event": 0,
-                },
-                "events_default": 0,
-                "historical": 100,
-                "invite": 50,
-                "kick": 50,
-                "redact": 50,
-                "state_default": 50,
-                "users": {"@sid1:red": 100},
-                "users_default": 0,
+                "custom.event": 0,
             },
-            self.power_levels(room_id),
+            self.power_levels(room_id)["events"],
         )
 
     @unittest.override_config(
@@ -1217,20 +1179,9 @@ def test_power_levels_with_server_override(self) -> None:
         room_id = self.helper.create_room_as(self.user_id)
         self.assertEqual(
             {
-                "ban": 50,
-                "events": {
-                    "custom.event": 0,
-                },
-                "events_default": 0,
-                "historical": 100,
-                "invite": 50,
-                "kick": 50,
-                "redact": 50,
-                "state_default": 50,
-                "users": {"@sid1:red": 100},
-                "users_default": 0,
+                "custom.event": 0,
             },
-            self.power_levels(room_id),
+            self.power_levels(room_id)["events"],
         )
 
     @unittest.override_config(
@@ -1246,7 +1197,7 @@ def test_power_levels_with_server_override(self) -> None:
     def test_power_levels_with_server_and_room_overrides(self) -> None:
         """
         With a server configured to modify the room-level defaults,
-        Create a room, providing different overrides.
+        create a room, providing different overrides.
         Confirm that the room's power levels reflect both overrides, and
         choose the room overrides where they clash.
         """
@@ -1258,28 +1209,21 @@ def test_power_levels_with_server_and_room_overrides(self) -> None:
             },
         )
 
+        # Room override wins over server config
         self.assertEqual(
-            {
-                "ban": 13,  # From server config override
-                "events": {
-                    "room.event": 0,  # From room override
-                },
-                "events_default": 0,
-                "historical": 100,
-                "invite": 50,
-                "kick": 50,
-                "redact": 50,
-                "state_default": 50,
-                "users": {"@sid1:red": 100},
-                "users_default": 0,
-            },
-            self.power_levels(room_id),
+            {"room.event": 0},
+            self.power_levels(room_id)["events"],
         )
 
+        # But where there is no room override, server config wins
+        self.assertEqual(13, self.power_levels(room_id)["ban"])
+
 
 class RoomPowerLevelOverridesInPracticeTestCase(RoomBase):
-    """Tests that we can really do various otherwise-prohibited actions
-    based on overriding the power levels in config."""
+    """
+    Tests that we can really do various otherwise-prohibited actions
+    based on overriding the power levels in config.
+    """
 
     user_id = "@sid1:red"
 
@@ -1311,7 +1255,7 @@ def test_normal_user_can_not_post_state_event(self) -> None:
         self.assertEqual(403, channel.code, msg=channel.result["body"])
         self.assertEqual(
             "You don't have permission to post that to the room. "
-            + "user_level (0) < send_level (50)",
+            "user_level (0) < send_level (50)",
             channel.json_body["error"],
         )
 
@@ -1323,8 +1267,8 @@ def test_normal_user_can_not_post_state_event(self) -> None:
         },
     )
     def test_with_config_override_normal_user_can_post_state_event(self) -> None:
-        # Given the server has config allowing normal users to post my event type
-        # And I am a normal member of a room
+        # Given the server has config allowing normal users to post my event type,
+        # and I am a normal member of a room
         room_id = self.helper.create_room_as("@some_other_guy:red")
         self.helper.join(room=room_id, user=self.user_id)
 
@@ -1373,9 +1317,9 @@ def test_any_room_override_defeats_config_override(self) -> None:
         },
     )
     def test_specific_room_override_defeats_config_override(self) -> None:
-        # Given the server has config allowing normal users to post my event type
-        # And I am a normal member of a room
-        # But the room was created with special permissions for this event type
+        # Given the server has config allowing normal users to post my event type,
+        # and I am a normal member of a room,
+        # but the room was created with special permissions for this event type
         extra_content = {
             "power_level_content_override": {"events": {"custom.event": 1}},
         }
@@ -1408,8 +1352,8 @@ def test_specific_room_override_defeats_config_override(self) -> None:
         },
     )
     def test_config_override_applies_only_to_specific_preset(self) -> None:
-        # Given the server has config for public_chats
-        # And I am a normal member of a private_chat room
+        # Given the server has config for public_chats,
+        # and I am a normal member of a private_chat room
         room_id = self.helper.create_room_as("@some_other_guy:red", is_public=False)
         self.helper.invite(room=room_id, src="@some_other_guy:red", targ=self.user_id)
         self.helper.join(room=room_id, user=self.user_id)