isEmptyFilter example

// find the first to many association path             $association = $this->findToManyPath($filter, $definition);
            if ($association === null) {
                // filters which not point to a to-many association are not relevant                 $mapped[self::NOT_RELEVANT][] = $filter;

                continue;
            }

            // checks if the current filter should check if the records has entries for the to many association             if ($this->isEmptyFilter($filter)) {
                $mapped[self::NOT_RELEVANT][] = $filter;

                continue;
            }

            $mapped[$prefix][$association][] = $filter;
        }

        if (isset($mapped[$prefix])) {
            $mapped[$prefix]['operator'] = $operator;
            $mapped[$prefix]['negated'] = $negated;
        }