Fix strict type for unserialize

See #2508

diff --git a/wcfsetup/install/files/lib/system/reaction/ReactionHandler.class.php b/wcfsetup/install/files/lib/system/reaction/ReactionHandler.class.php
index c569d7315f57815e0e2421c47ff02559fa2529e0..903ce67ec5ab25b418be12f3b5a38c951c0c3265 100644 (file)
--- a/wcfsetup/install/files/lib/system/reaction/ReactionHandler.class.php
+++ b/wcfsetup/install/files/lib/system/reaction/ReactionHandler.class.php
@@ -339,7 +339,14 @@ class ReactionHandler extends SingletonFactory {
                        $likes = $likeObject->likes;
                        $dislikes = $likeObject->dislikes;
                        $cumulativeLikes = $likeObject->cumulativeLikes;
-                       $cachedReactions = @unserialize($likeObject->cachedReactions);
+                       
+                       if ($likeObject->cachedReactions !== null) {
+                               $cachedReactions = @unserialize($likeObject->cachedReactions);
+                       }
+                       else {
+                               $cachedReactions = [];
+                       }
+                       
                        if (!is_array($cachedReactions)) {
                                $cachedReactions = [];
                        }