Return error when peer is not valid (#1573)

Fix count with invalid peers

management/server/group.go

@@ -115,6 +115,13 @@ func (am *DefaultAccountManager) SaveGroup(accountID, userID string, newGroup *G
 	if err != nil {
 		return err
 	}
+
+	for _, peerID := range newGroup.Peers {
+		if account.Peers[peerID] == nil {
+			return status.Errorf(status.InvalidArgument, "peer with ID \"%s\" not found", peerID)
+		}
+	}
+
 	oldGroup, exists := account.Groups[newGroup.ID]
 	account.Groups[newGroup.ID] = newGroup
 

management/server/http/groups_handler.go

@@ -240,10 +240,9 @@ func (h *GroupsHandler) GetGroup(w http.ResponseWriter, r *http.Request) {
 func toGroupResponse(account *server.Account, group *server.Group) *api.Group {
 	cache := make(map[string]api.PeerMinimum)
 	gr := api.Group{
-		Id:         group.ID,
-		Name:       group.Name,
-		PeersCount: len(group.Peers),
-		Issued:     &group.Issued,
+		Id:     group.ID,
+		Name:   group.Name,
+		Issued: &group.Issued,
 	}
 
 	for _, pid := range group.Peers {
@@ -261,5 +260,8 @@ func toGroupResponse(account *server.Account, group *server.Group) *api.Group {
 			gr.Peers = append(gr.Peers, peerResp)
 		}
 	}
+
+	gr.PeersCount = len(gr.Peers)
+
 	return &gr
 }