1 files changed, 6 insertions, 2 deletions
diff --git a/lib/private/Files/Cache/QuerySearchHelper.php b/lib/private/Files/Cache/QuerySearchHelper.php
index 2d9d8f374f7..47380b72ffa 100644
--- a/lib/private/Files/Cache/QuerySearchHelper.php
+++ b/lib/private/Files/Cache/QuerySearchHelper.php
@@ -88,14 +88,18 @@ class QuerySearchHelper {
 	 * @param ISearchOperator $operator
 	 */
 	public function searchOperatorArrayToDBExprArray(IQueryBuilder $builder, array $operators) {
-		return array_map(function ($operator) use ($builder) {
+		return array_filter(array_map(function ($operator) use ($builder) {
 			return $this->searchOperatorToDBExpr($builder, $operator);
-		}, $operators);
+		}, $operators));
 	}
 
 	public function searchOperatorToDBExpr(IQueryBuilder $builder, ISearchOperator $operator) {
 		$expr = $builder->expr();
 		if ($operator instanceof ISearchBinaryOperator) {
+			if (count($operator->getArguments()) === 0) {
+				return null;
+			}
+
 			switch ($operator->getType()) {
 				case ISearchBinaryOperator::OPERATOR_NOT:
 					$negativeOperator = $operator->getArguments()[0];