Examine all m.direct rooms to find a DM as fallback (#10127)

src/utils/DMRoomMap.ts

@@ -192,6 +192,16 @@ export default class DMRoomMap {
             .reduce((obj, r) => (obj[r.userId] = r.room) && obj, {});
     }
 
+    /**
+     * @returns all room Ids from m.direct
+     */
+    public getRoomIds(): Set<string> {
+        return Object.values(this.mDirectEvent).reduce((prevRoomIds: Set<string>, roomIds: string[]): Set<string> => {
+            roomIds.forEach((roomId) => prevRoomIds.add(roomId));
+            return prevRoomIds;
+        }, new Set<string>());
+    }
+
     private getUserToRooms(): { [key: string]: string[] } {
         if (!this.userToRooms) {
             const userToRooms = this.mDirectEvent;

src/utils/dm/findDMForUser.ts

@@ -21,17 +21,8 @@ import { isLocalRoom } from "../localRoom/isLocalRoom";
 import { isJoinedOrNearlyJoined } from "../membership";
 import { getFunctionalMembers } from "../room/getFunctionalMembers";
 
-/**
- * Tries to find a DM room with a specific user.
- *
- * @param {MatrixClient} client
- * @param {string} userId ID of the user to find the DM for
- * @returns {Room} Room if found
- */
-export function findDMForUser(client: MatrixClient, userId: string): Room {
-    const roomIds = DMRoomMap.shared().getDMRoomsForUserId(userId);
-    const rooms = roomIds.map((id) => client.getRoom(id));
-    const suitableDMRooms = rooms
+function extractSuitableRoom(rooms: Room[], userId: string): Room | undefined {
+    const suitableRooms = rooms
         .filter((r) => {
             // Validate that we are joined and the other person is also joined. We'll also make sure
             // that the room also looks like a DM (until we have canonical DMs to tell us). For now,
@@ -44,7 +35,7 @@ export function findDMForUser(client: MatrixClient, userId: string): Room {
                 const functionalUsers = getFunctionalMembers(r);
                 const members = r.currentState.getMembers();
                 const joinedMembers = members.filter(
-                    (m) => !functionalUsers.includes(m.userId) && isJoinedOrNearlyJoined(m.membership),
+                    (m) => !functionalUsers.includes(m.userId) && m.membership && isJoinedOrNearlyJoined(m.membership),
                 );
                 const otherMember = joinedMembers.find((m) => m.userId === userId);
                 return otherMember && joinedMembers.length === 2;
@@ -54,7 +45,34 @@ export function findDMForUser(client: MatrixClient, userId: string): Room {
         .sort((r1, r2) => {
             return r2.getLastActiveTimestamp() - r1.getLastActiveTimestamp();
         });
-    if (suitableDMRooms.length) {
-        return suitableDMRooms[0];
+
+    if (suitableRooms.length) {
+        return suitableRooms[0];
     }
+
+    return undefined;
+}
+
+/**
+ * Tries to find a DM room with a specific user.
+ *
+ * @param {MatrixClient} client
+ * @param {string} userId ID of the user to find the DM for
+ * @returns {Room | undefined} Room if found
+ */
+export function findDMForUser(client: MatrixClient, userId: string): Room | undefined {
+    const roomIdsForUserId = DMRoomMap.shared().getDMRoomsForUserId(userId);
+    const roomsForUserId = roomIdsForUserId.map((id) => client.getRoom(id)).filter((r): r is Room => r !== null);
+    const suitableRoomForUserId = extractSuitableRoom(roomsForUserId, userId);
+
+    if (suitableRoomForUserId) {
+        return suitableRoomForUserId;
+    }
+
+    // Try to find in all rooms as a fallback
+    const allRoomIds = DMRoomMap.shared().getRoomIds();
+    const allRooms = Array.from(allRoomIds)
+        .map((id) => client.getRoom(id))
+        .filter((r): r is Room => r !== null);
+    return extractSuitableRoom(allRooms, userId);
 }

src/utils/dm/findDMRoom.ts

@@ -29,7 +29,7 @@ import { findDMForUser } from "./findDMForUser";
  */
 export function findDMRoom(client: MatrixClient, targets: Member[]): Room | null {
     const targetIds = targets.map((t) => t.userId);
-    let existingRoom: Room;
+    let existingRoom: Room | undefined;
     if (targetIds.length === 1) {
         existingRoom = findDMForUser(client, targetIds[0]);
     } else {