diff --git a/src/moduleutils/moduleutils.php b/src/moduleutils/moduleutils.php
index 2e138fd..8ef5b26 100644
--- a/src/moduleutils/moduleutils.php
+++ b/src/moduleutils/moduleutils.php
@@ -1,49 +1,52 @@
 <?php
 
-function phutil_get_library_root($library) {
+function phutil_get_library_root($library = null) {
+  if (!$library) {
+    $library = phutil_get_current_library_name();
+  }
   $bootloader = PhutilBootloader::getInstance();
   return $bootloader->getLibraryRoot($library);
 }
 
 function phutil_get_library_root_for_path($path) {
   foreach (Filesystem::walkToRoot($path) as $dir) {
     if (Filesystem::pathExists($dir.'/__phutil_library_init__.php')) {
       return $dir;
     }
   }
   return null;
 }
 
 function phutil_get_library_name_for_root($path) {
   $path = rtrim(Filesystem::resolvePath($path), '/');
 
   $bootloader = PhutilBootloader::getInstance();
   $libraries = $bootloader->getAllLibraries();
   foreach ($libraries as $library) {
     $root = $bootloader->getLibraryRoot($library);
     if (rtrim(Filesystem::resolvePath($root), '/') == $path) {
       return $library;
     }
   }
 
   return null;
 }
 
 function phutil_get_current_library_name() {
   $caller = head(debug_backtrace(false));
 
   $root = phutil_get_library_root_for_path($caller['file']);
   return phutil_get_library_name_for_root($root);
 }
 
 /**
  * Warns about use of deprecated behavior.
  */
 function phutil_deprecated($what, $why) {
   PhutilErrorHandler::dispatchErrorMessage(
     PhutilErrorHandler::DEPRECATED,
     $what,
     array(
       'why' => $why,
     ));
 }