Fixed a crash in member list loading (#1199)

src/MemberList.cpp

@@ -40,14 +40,17 @@ MemberListBackend::MemberListBackend(const QString &room_id, QObject *parent)
 void
 MemberListBackend::addUsers(const std::vector<RoomMember> &members)
 {
+    auto thisRoom = ChatPage::instance()->timelineManager()->rooms()->getRoomById(room_id_);
+    if (thisRoom.isNull()) {
+        nhlog::ui()->error("Could not load the current room");
+        return;
+    }
+
     beginInsertRows(
       QModelIndex{}, m_memberList.count(), m_memberList.count() + (int)members.size() - 1);
 
     for (const auto &member : members)
-        m_memberList.push_back(
-          {member,
-           ChatPage::instance()->timelineManager()->rooms()->currentRoom()->avatarUrl(
-             member.user_id)});
+        m_memberList.push_back({member, thisRoom->avatarUrl(member.user_id)});
 
     endInsertRows();
 }