diff --git a/lib/Github/Api/GitData/Trees.php b/lib/Github/Api/GitData/Trees.php
index d514d9f8205..939e8619b73 100644
--- a/lib/Github/Api/GitData/Trees.php
+++ b/lib/Github/Api/GitData/Trees.php
@@ -54,7 +54,7 @@ public function create($username, $repository, array $params)
             }
 
             // If `sha` is not set, `content` is required
-            if (!isset($tree['sha']) && !isset($tree['content'])) {
+            if (!array_key_exists('sha', $tree) && !isset($tree['content'])) {
                 throw new MissingArgumentException("tree.$key.content");
             }
         }