Ignore functional members in admin rooms (#1782)

* Support functional member filtering out of admin rooms.

* tidyup

* Add test

* lint

* changelog

* Add ignoreFunctionalMembersInAdminRooms to schema

* Add sample config change

changelog.d/1782.misc

@@ -0,0 +1 @@
+Add option to ignore "functional members" when checking if an admin room contains two users.

config.sample.yaml

@@ -604,6 +604,8 @@ ircService:
     longReplyTemplate: "<$NICK> \"$ORIGINAL\" <- $REPLY"
     # how much time needs to pass between the reply and the original message to switch to the long format
     shortReplyTresholdSeconds: 300
+    # Ignore users mentioned in a io.element.functional_members state event when checking admin room membership
+    ignoreFunctionalMembersInAdminRooms: false
 
   # Maximum number of montly active users, beyond which the bridge gets blocked (both ways)
   # RMAUlimit: 100
@@ -701,4 +703,4 @@ database:
 #   # The Redis URI to connect to 
 #   redisUrl: redis://user:password@host:port/dbnum
 #   # Should the connections persist after the bridge successfully shuts down?
-#   persistConnectionsOnShutdown: true
+#   persistConnectionsOnShutdown: true

config.schema.yml

@@ -171,6 +171,8 @@ properties:
                         type: "string"
                     shortReplyTresholdSeconds:
                         type: "integer"
+                    ignoreFunctionalMembersInAdminRooms:
+                        type: "boolean"
             ircHandler:
                 type: "object"
                 properties:

spec/integ/admin-rooms.spec.js

@@ -1065,6 +1065,87 @@ describe("Admin rooms", function() {
             );
     });
 
+    it("mx bot should be NOT kicked when there are > 2 users in room and functional members are present", async () => {
+
+        const intent = env.clientMock._intent(botUserId);
+        const sdk = intent.underlyingClient;
+        sdk.getRoomState.and.callFake(
+            function (roomId) {
+                expect(roomId).toBe(adminRoomId, 'Room state returned should be for admin room');
+                return Promise.resolve([
+                    {
+                        content: {membership: "join"},
+                        type: "m.room.member",
+                        state_key: "@bot:fake"
+                    },
+                    {
+                        content: {membership: "join"},
+                        type: "m.room.member",
+                        state_key: "@user1:fake"
+                    },
+                    {
+                        content: {membership: "join"},
+                        type: "m.room.member",
+                        state_key: "@user2:fake"
+                    }, {
+                        type: "io.element.functional_members",
+                        state_key: "",
+                        content: {
+                            service_members: ["@user2:fake"]
+                        }
+                    }
+                ]);
+            }
+        );
+
+        intent.leaveRoom.and.callFake(function(roomId) {
+            fail('Bot should not leave room');
+        });
+
+        let sentMessage = true;
+        sdk.sendEvent.and.callFake((roomId, type, content) => {
+            expect(roomId).toBe(adminRoomId, 'Bot did not send message to admin room');
+            sentMessage = true;
+            return Promise.resolve({});
+        });
+
+        await env.mockAppService._trigger("type:m.room.member", {
+            content: {
+                membership: "join",
+            },
+            state_key: botUserId,
+            sender: "@user1:localhost",
+            room_id: adminRoomId,
+            type: "m.room.member"
+        });
+
+        await env.mockAppService._trigger("type:m.room.member", {
+            content: {
+                membership: "join",
+            },
+            state_key: botUserId,
+            sender: "@user2:localhost",
+            room_id: adminRoomId,
+            type: "m.room.member"
+        });
+
+        // trigger the bot to leave
+        await env.mockAppService._trigger("type:m.room.message", {
+            content: {
+                body: "!help",
+                msgtype: "m.text"
+            },
+            sender: "@user2:localhost",
+            room_id: adminRoomId,
+            type: "m.room.message"
+        }).then(
+            () => {
+                expect(sentMessage).toBe(true);
+            },
+            (err) => {console.log(err)}
+        );
+});
+
     it("mx bot should NOT be kicked when there are 2 users in room and a message is sent", async () => {
             const intent = env.clientMock._intent(botUserId);
             const sdk = intent.underlyingClient;

spec/util/test-config.json

@@ -43,6 +43,9 @@
         "ircHandler": {
             "powerLevelGracePeriodMs": 500
         },
+        "matrixHandler": {
+            "ignoreFunctionalMembersInAdminRooms": true
+        },
         "servers": {
             "irc.example": {
                 "port": 6667,

src/bridge/MatrixHandler.ts

@@ -38,6 +38,12 @@ async function reqHandler(req: BridgeRequest, promise: PromiseLike<unknown>|void
 const MSG_PMS_DISABLED = "[Bridge] Sorry, PMs are disabled on this bridge.";
 const MSG_PMS_DISABLED_FEDERATION = "[Bridge] Sorry, PMs are disabled on this bridge over federation.";
 
+const FUNCTIONAL_MEMBERS_EVENT = "io.element.functional_members";
+
+interface FunctionalMembersEventContent {
+    service_members: string[];
+}
+
 export interface MatrixHandlerConfig {
     /* Number of events to store in memory for use in replies. */
     eventCacheSize: number;
@@ -51,6 +57,9 @@ export interface MatrixHandlerConfig {
     longReplyTemplate: string;
     // Format of the text explaining why a message is truncated and pastebinned
     truncatedMessageTemplate: string;
+    // Ignore io.element.functional_members members joining admin rooms.
+    // See https://github.com/vector-im/element-meta/blob/develop/spec/functional_members.md
+    ignoreFunctionalMembersInAdminRooms: boolean;
 }
 
 export const DEFAULTS: MatrixHandlerConfig = {
@@ -60,6 +69,7 @@ export const DEFAULTS: MatrixHandlerConfig = {
     shortReplyTemplate: "$NICK: $REPLY",
     longReplyTemplate: "<$NICK> \"$ORIGINAL\" <- $REPLY",
     truncatedMessageTemplate: "(full message at <$URL>)",
+    ignoreFunctionalMembersInAdminRooms: false,
 };
 
 export interface MatrixEventInvite {
@@ -277,8 +287,18 @@ export class MatrixHandler {
             (m.content as {membership: string}).membership === "join"
         );
 
+        let functionalMembers = this.config.ignoreFunctionalMembersInAdminRooms &&
+            ((
+                this.memberTracker?.getState(adminRoom.getId(), FUNCTIONAL_MEMBERS_EVENT, "") as StateLookupEvent|null
+            )?.content as FunctionalMembersEventContent)?.service_members || [];
+
+        if (!Array.isArray(functionalMembers)) {
+            // Guard against invalid types.
+            functionalMembers = [];
+        }
+
         // If an admin room has more than 2 people in it, kick the bot out
-        if (members.length > 2) {
+        if (members.filter(m => !functionalMembers.includes(m.state_key)).length > 2) {
             req.log.error(
                 `onAdminMessage: admin room has ${members.length}` +
                 ` users instead of just 2; bot will leave`