diff --git a/src/applications/diffusion/conduit/DiffusionBranchQueryConduitAPIMethod.php b/src/applications/diffusion/conduit/DiffusionBranchQueryConduitAPIMethod.php
--- a/src/applications/diffusion/conduit/DiffusionBranchQueryConduitAPIMethod.php
+++ b/src/applications/diffusion/conduit/DiffusionBranchQueryConduitAPIMethod.php
@@ -80,7 +80,7 @@
       ->setRepository($repository);
 
     $contains = $request->getValue('contains');
-    if (strlen($contains)) {
+    if (phutil_nonempty_string($contains)) {
       $query->withContainsCommit($contains);
     }