diff --git a/src/applications/herald/adapter/HeraldCommitAdapter.php b/src/applications/herald/adapter/HeraldCommitAdapter.php
index e872bbb725..85dfcb30fc 100644
--- a/src/applications/herald/adapter/HeraldCommitAdapter.php
+++ b/src/applications/herald/adapter/HeraldCommitAdapter.php
@@ -175,13 +175,13 @@ final class HeraldCommitAdapter extends HeraldObjectAdapter {
       case HeraldFieldConfig::FIELD_DIFFERENTIAL_REVIEWERS:
         $revision = $this->loadDifferentialRevision();
         if (!$revision) {
-          return null;
+          return array();
         }
         return $revision->getReviewers();
       case HeraldFieldConfig::FIELD_DIFFERENTIAL_CCS:
         $revision = $this->loadDifferentialRevision();
         if (!$revision) {
-          return null;
+          return array();
         }
         return $revision->getCCPHIDs();
       default: