[MM-59519] preserve DM/GM unread/read state over export and import (#27707)

server/channels/store/sqlstore/channel_store.go

@@ -4088,7 +4088,7 @@ func (s SqlChannelStore) GetAllDirectChannelsForExportAfter(limit int, afterId s
 		channelIds = append(channelIds, channel.Id)
 	}
 	query = s.getQueryBuilder().
-		Select("u.Username as Username, ChannelId, UserId, cm.Roles as Roles, LastViewedAt, MsgCount, MentionCount, MentionCountRoot, COALESCE(UrgentMentionCount, 0) UrgentMentionCount, cm.NotifyProps as NotifyProps, LastUpdateAt, SchemeUser, SchemeAdmin, (SchemeGuest IS NOT NULL AND SchemeGuest) as SchemeGuest").
+		Select("u.Username as Username, ChannelId, UserId, cm.Roles as Roles, LastViewedAt, MsgCount, MsgCountRoot, MentionCount, MentionCountRoot, COALESCE(UrgentMentionCount, 0) UrgentMentionCount, cm.NotifyProps as NotifyProps, LastUpdateAt, SchemeUser, SchemeAdmin, (SchemeGuest IS NOT NULL AND SchemeGuest) as SchemeGuest").
 		From("ChannelMembers cm").
 		Join("Users u ON ( u.Id = cm.UserId )").
 		Where(sq.Eq{"cm.ChannelId": channelIds})
@@ -4106,12 +4106,11 @@ func (s SqlChannelStore) GetAllDirectChannelsForExportAfter(limit int, afterId s
 	// Populate each channel with its members
 	dmChannelsMap := make(map[string]*model.DirectChannelForExport)
 	for _, channel := range directChannelsForExport {
-		channel.Members = &[]string{}
+		channel.Members = []*model.ChannelMemberForExport{}
 		dmChannelsMap[channel.Id] = channel
 	}
 	for _, member := range channelMembers {
-		members := dmChannelsMap[member.ChannelId].Members
-		*members = append(*members, member.Username)
+		dmChannelsMap[member.ChannelId].Members = append(dmChannelsMap[member.ChannelId].Members, member)
 	}
 
 	return directChannelsForExport, nil