diff --git a/lib/private/Files/Cache/Cache.php b/lib/private/Files/Cache/Cache.php
index f1b4b48a1b..b84d9b218b 100644
--- a/lib/private/Files/Cache/Cache.php
+++ b/lib/private/Files/Cache/Cache.php
@@ -190,10 +190,10 @@ class Cache implements ICache {
 		}
 		$data['permissions'] = (int)$data['permissions'];
 		if (isset($data['creation_time'])) {
-			$data['creation_time'] = (int) $data['creation_time'];
+			$data['creation_time'] = (int)$data['creation_time'];
 		}
 		if (isset($data['upload_time'])) {
-			$data['upload_time'] = (int) $data['upload_time'];
+			$data['upload_time'] = (int)$data['upload_time'];
 		}
 		return new CacheEntry($data);
 	}
@@ -819,6 +819,10 @@ class Cache implements ICache {
 		$query->whereStorageId();
 
 		if ($this->querySearchHelper->shouldJoinTags($searchQuery->getSearchOperation())) {
+			$user = $searchQuery->getUser();
+			if ($user === null) {
+				throw new \InvalidArgumentException("Searching by tag requires the user to be set in the query");
+			}
 			$query
 				->innerJoin('file', 'vcategory_to_object', 'tagmap', $builder->expr()->eq('file.fileid', 'tagmap.objid'))
 				->innerJoin('tagmap', 'vcategory', 'tag', $builder->expr()->andX(
@@ -826,7 +830,7 @@ class Cache implements ICache {
 					$builder->expr()->eq('tagmap.categoryid', 'tag.id')
 				))
 				->andWhere($builder->expr()->eq('tag.type', $builder->createNamedParameter('files')))
-				->andWhere($builder->expr()->eq('tag.uid', $builder->createNamedParameter($searchQuery->getUser()->getUID())));
+				->andWhere($builder->expr()->eq('tag.uid', $builder->createNamedParameter($user->getUID())));
 		}
 
 		$searchExpr = $this->querySearchHelper->searchOperatorToDBExpr($builder, $searchQuery->getSearchOperation());
@@ -1007,7 +1011,7 @@ class Cache implements ICache {
 			return null;
 		}
 
-		return (string) $path;
+		return (string)$path;
 	}
 
 	/**
diff --git a/lib/private/Files/Search/SearchQuery.php b/lib/private/Files/Search/SearchQuery.php
index b7b8b80110..091fe57d21 100644
--- a/lib/private/Files/Search/SearchQuery.php
+++ b/lib/private/Files/Search/SearchQuery.php
@@ -37,7 +37,7 @@ class SearchQuery implements ISearchQuery {
 	private $offset;
 	/** @var  ISearchOrder[] */
 	private $order;
-	/** @var IUser */
+	/** @var ?IUser */
 	private $user;
 	private $limitToHome;
 
@@ -48,7 +48,7 @@ class SearchQuery implements ISearchQuery {
 	 * @param int $limit
 	 * @param int $offset
 	 * @param array $order
-	 * @param IUser $user
+	 * @param ?IUser $user
 	 * @param bool $limitToHome
 	 */
 	public function __construct(
@@ -56,7 +56,7 @@ class SearchQuery implements ISearchQuery {
 		int $limit,
 		int $offset,
 		array $order,
-		IUser $user,
+		?IUser $user = null,
 		bool $limitToHome = false
 	) {
 		$this->searchOperation = $searchOperation;
@@ -96,7 +96,7 @@ class SearchQuery implements ISearchQuery {
 	}
 
 	/**
-	 * @return IUser
+	 * @return ?IUser
 	 */
 	public function getUser() {
 		return $this->user;
diff --git a/lib/public/Files/Search/ISearchQuery.php b/lib/public/Files/Search/ISearchQuery.php
index 4d866f8d7b..dd7c901f7f 100644
--- a/lib/public/Files/Search/ISearchQuery.php
+++ b/lib/public/Files/Search/ISearchQuery.php
@@ -62,7 +62,7 @@ interface ISearchQuery {
 	/**
 	 * The user that issued the search
 	 *
-	 * @return IUser
+	 * @return ?IUser
 	 * @since 12.0.0
 	 */
 	public function getUser();
diff --git a/tests/lib/Files/Node/FolderTest.php b/tests/lib/Files/Node/FolderTest.php
index 1ba052b8de..6d3367ac09 100644
--- a/tests/lib/Files/Node/FolderTest.php
+++ b/tests/lib/Files/Node/FolderTest.php
@@ -305,10 +305,9 @@ class FolderTest extends NodeTest {
 			->willReturn('foo');
 
 		$cache->expects($this->once())
-			->method('search')
-			->with('%qw%')
+			->method('searchQuery')
 			->willReturn([
-				['fileid' => 3, 'path' => 'foo/qwerty', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain']
+				new CacheEntry(['fileid' => 3, 'path' => 'foo/qwerty', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain'])
 			]);
 
 		$root->expects($this->once())
@@ -358,11 +357,10 @@ class FolderTest extends NodeTest {
 			->willReturn($cache);
 
 		$cache->expects($this->once())
-			->method('search')
-			->with('%qw%')
+			->method('searchQuery')
 			->willReturn([
-				['fileid' => 3, 'path' => 'files/foo', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain'],
-				['fileid' => 3, 'path' => 'files_trashbin/foo2.d12345', 'name' => 'foo2.d12345', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain'],
+				new CacheEntry(['fileid' => 3, 'path' => 'files/foo', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain']),
+				new CacheEntry(['fileid' => 3, 'path' => 'files_trashbin/foo2.d12345', 'name' => 'foo2.d12345', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain']),
 			]);
 
 		$root->expects($this->once())
@@ -409,10 +407,9 @@ class FolderTest extends NodeTest {
 			->willReturn($cache);
 
 		$cache->expects($this->once())
-			->method('search')
-			->with('%qw%')
+			->method('searchQuery')
 			->willReturn([
-				['fileid' => 3, 'path' => 'foo/qwerty', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain']
+				new CacheEntry(['fileid' => 3, 'path' => 'foo/qwerty', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain'])
 			]);
 
 		$root->expects($this->once())
@@ -475,17 +472,15 @@ class FolderTest extends NodeTest {
 			->willReturn($subCache);
 
 		$cache->expects($this->once())
-			->method('search')
-			->with('%qw%')
+			->method('searchQuery')
 			->willReturn([
-				['fileid' => 3, 'path' => 'foo/qwerty', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain']
+				new CacheEntry(['fileid' => 3, 'path' => 'foo/qwerty', 'name' => 'qwerty', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain'])
 			]);
 
 		$subCache->expects($this->once())
-			->method('search')
-			->with('%qw%')
+			->method('searchQuery')
 			->willReturn([
-				['fileid' => 4, 'path' => 'asd/qweasd', 'name' => 'qweasd', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain']
+				new CacheEntry(['fileid' => 4, 'path' => 'asd/qweasd', 'name' => 'qweasd', 'size' => 200, 'mtime' => 55, 'mimetype' => 'text/plain'])
 			]);
 
 		$root->expects($this->once())