diff --git a/src/Cache/RedisCacheTagsChecksum.php b/src/Cache/RedisCacheTagsChecksum.php
index a5f03dd..d2e9c79 100644
--- a/src/Cache/RedisCacheTagsChecksum.php
+++ b/src/Cache/RedisCacheTagsChecksum.php
@@ -83,7 +83,7 @@ class RedisCacheTagsChecksum implements CacheTagsChecksumInterface, CacheTagsInv
     // combine it with the tags array to get the expected return value and run
     // it through intval() to convert to integers and FALSE to 0.
     $values = $this->client->mget($keys);
-    return $values ? array_map('intval', array_combine($tags, $values)) : [];
+    return is_array($values) ? array_map('intval', array_combine($tags, $values)) : [];
   }
 
   /**