diff --git a/src/ObsAdapter.php b/src/ObsAdapter.php
index 98e37ee..2cb237c 100644
--- a/src/ObsAdapter.php
+++ b/src/ObsAdapter.php
@@ -403,9 +403,15 @@ private function extractExtraMetadata(array $metadata): array
         $extracted = [];
 
         foreach (self::EXTRA_METADATA_FIELDS as $field) {
-            if (isset($metadata[$field]) && $metadata[$field] !== '') {
-                $extracted[$field] = $metadata[$field];
+            if (! isset($metadata[$field])) {
+                continue;
             }
+
+            if ($metadata[$field] === '') {
+                continue;
+            }
+
+            $extracted[$field] = $metadata[$field];
         }
 
         return $extracted;
@@ -467,7 +473,7 @@ protected function getObject(string $path): StreamInterface
     public function listDirObjects(string $dirname = '', bool $recursive = false): array
     {
         $prefix = trim($this->pathPrefixer->prefixPath($dirname), '/');
-        $prefix = empty($prefix) ? '' : $prefix . '/';
+        $prefix = $prefix === '' ? '' : $prefix . '/';
 
         $nextMarker = '';
 
@@ -511,7 +517,7 @@ public function listDirObjects(string $dirname = '', bool $recursive = false): a
     private function processObjects(array $result, ?array $objects, string $dirname): array
     {
         $result['objects'] = [];
-        if (! empty($objects)) {
+        if ($objects !== null && $objects !== []) {
             foreach ($objects as $object) {
                 $object['Prefix'] = $dirname;
                 $result['objects'][] = $object;
@@ -529,7 +535,7 @@ private function processObjects(array $result, ?array $objects, string $dirname)
      */
     private function processPrefixes(array $result, ?array $prefixes): array
     {
-        if (! empty($prefixes)) {
+        if ($prefixes !== null && $prefixes !== []) {
             foreach ($prefixes as $prefix) {
                 $result['prefix'][] = $prefix['Prefix'];
             }