diff --git a/src/infrastructure/export/engine/PhabricatorProjectsExportEngineExtension.php b/src/infrastructure/export/engine/PhabricatorProjectsExportEngineExtension.php
--- a/src/infrastructure/export/engine/PhabricatorProjectsExportEngineExtension.php
+++ b/src/infrastructure/export/engine/PhabricatorProjectsExportEngineExtension.php
@@ -24,6 +24,9 @@
     $viewer = $this->getViewer();
 
     $object_phids = mpull($objects, 'getPHID');
+    if (!$object_phids) {
+      return array();
+    }
 
     $projects_query = id(new PhabricatorEdgeQuery())
       ->withSourcePHIDs($object_phids)
diff --git a/src/infrastructure/export/engine/PhabricatorSubscriptionsExportEngineExtension.php b/src/infrastructure/export/engine/PhabricatorSubscriptionsExportEngineExtension.php
--- a/src/infrastructure/export/engine/PhabricatorSubscriptionsExportEngineExtension.php
+++ b/src/infrastructure/export/engine/PhabricatorSubscriptionsExportEngineExtension.php
@@ -24,6 +24,9 @@
     $viewer = $this->getViewer();
 
     $object_phids = mpull($objects, 'getPHID');
+    if (!$object_phids) {
+      return array();
+    }
 
     $projects_query = id(new PhabricatorEdgeQuery())
       ->withSourcePHIDs($object_phids)