ignore user limit if user already registered

backend/server/internal/database/db.go

@@ -153,6 +153,19 @@ func (db *DB) DistinctUsers(ctx context.Context) (int64, error) {
 	return numDistinctUsers, nil
 }
 
+func (db *DB) UserAlreadyExist(ctx context.Context, userID string) (bool, error) {
+	var cnt int64
+	tx := db.WithContext(ctx).Table("devices").Where("user_id = ?", userID).Count(&cnt)
+	if tx.Error != nil {
+		return false, fmt.Errorf("tx.Error: %w", tx.Error)
+	}
+
+	if cnt > 0 {
+		return true, nil
+	}
+	return false, nil
+}
+
 func (db *DB) DumpRequestCreate(ctx context.Context, req *shared.DumpRequest) error {
 	tx := db.WithContext(ctx).Create(req)
 	if tx.Error != nil {
@@ -409,7 +422,7 @@ func (db *DB) DeepClean(ctx context.Context) error {
 			FROM devices
 			GROUP BY user_id
 			HAVING COUNT(DISTINCT device_id) = 1
-		)	
+		)
 		`)
 		if r.Error != nil {
 			return fmt.Errorf("failed to create list of single device users: %w", r.Error)
@@ -419,7 +432,7 @@ func (db *DB) DeepClean(ctx context.Context) error {
 			SELECT user_id
 			FROM usage_data
 			WHERE last_used <= (now() - INTERVAL '180 days')
-		)	
+		)
 		`)
 		if r.Error != nil {
 			return fmt.Errorf("failed to create list of inactive users: %w", r.Error)

backend/server/internal/server/api_handlers.go

@@ -201,18 +201,26 @@ func (s *Server) apiDownloadHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 func (s *Server) apiRegisterHandler(w http.ResponseWriter, r *http.Request) {
+	userId := getRequiredQueryParam(r, "user_id")
+	deviceId := getRequiredQueryParam(r, "device_id")
+	isIntegrationTestDevice := getOptionalQueryParam(r, "is_integration_test_device", false) == "true"
+
 	if getMaximumNumberOfAllowedUsers() < math.MaxInt {
-		numDistinctUsers, err := s.db.DistinctUsers(r.Context())
+		userAlreadyExist, err := s.db.UserAlreadyExist(r.Context(), userId)
 		if err != nil {
-			panic(fmt.Errorf("db.DistinctUsers: %w", err))
+			panic(fmt.Errorf("db.UserAlreadyExist: %w", err))
 		}
-		if numDistinctUsers >= int64(getMaximumNumberOfAllowedUsers()) {
-			panic(fmt.Sprintf("Refusing to allow registration of new device since there are currently %d users and this server allows a max of %d users", numDistinctUsers, getMaximumNumberOfAllowedUsers()))
+
+		if !userAlreadyExist {
+			numDistinctUsers, err := s.db.DistinctUsers(r.Context())
+			if err != nil {
+				panic(fmt.Errorf("db.DistinctUsers: %w", err))
+			}
+			if numDistinctUsers >= int64(getMaximumNumberOfAllowedUsers()) {
+				panic(fmt.Sprintf("Refusing to allow registration of new device since there are currently %d users and this server allows a max of %d users", numDistinctUsers, getMaximumNumberOfAllowedUsers()))
+			}
 		}
 	}
-	userId := getRequiredQueryParam(r, "user_id")
-	deviceId := getRequiredQueryParam(r, "device_id")
-	isIntegrationTestDevice := getOptionalQueryParam(r, "is_integration_test_device", false) == "true"
 
 	existingDevicesCount, err := s.db.CountDevicesForUser(r.Context(), userId)
 	checkGormError(err)