diff --git a/src/applications/celerity/controller/CelerityResourceController.php b/src/applications/celerity/controller/CelerityResourceController.php
--- a/src/applications/celerity/controller/CelerityResourceController.php
+++ b/src/applications/celerity/controller/CelerityResourceController.php
@@ -59,6 +59,7 @@
     }
 
     $cache = null;
+    $cache_key = null;
     $data = null;
     if ($is_cacheable && $is_locally_cacheable && !$dev_mode) {
       $cache = PhabricatorCaches::getImmutableCache();