diff --git a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
--- a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
+++ b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
@@ -872,7 +872,7 @@
   protected function readBoolFromRequest(
     AphrontRequest $request,
     $key) {
-    if (!strlen($request->getStr($key))) {
+    if (!phutil_nonempty_string($request->getStr($key))) {
       return null;
     }
     return $request->getBool($key);