commit 929b83d97b6f2747e58a6a58a2a5d76b92a8a248
Author: fago <nuppla@zites.net>
Date:   Thu Feb 28 10:49:19 2013 +0100

    Use drupal_strlen

diff --git a/core/lib/Drupal/Core/TypedData/ItemList.php b/core/lib/Drupal/Core/TypedData/ItemList.php
index 4230ddc..3c6d01a 100644
--- a/core/lib/Drupal/Core/TypedData/ItemList.php
+++ b/core/lib/Drupal/Core/TypedData/ItemList.php
@@ -79,7 +79,8 @@ public function getString() {
       foreach ($this->list as $item) {
         $strings[] = $item->getString();
       }
-      return implode(', ', array_filter($strings, 'strlen'));
+      // Remove any empty strings resulting from empty items.
+      return implode(', ', array_filter($strings, 'drupal_strlen'));
     }
   }
 
diff --git a/core/lib/Drupal/Core/TypedData/Type/Map.php b/core/lib/Drupal/Core/TypedData/Type/Map.php
index d7df77a..01598d0 100644
--- a/core/lib/Drupal/Core/TypedData/Type/Map.php
+++ b/core/lib/Drupal/Core/TypedData/Type/Map.php
@@ -78,7 +78,8 @@ public function getString() {
     foreach ($this->getProperties() as $property) {
       $strings[] = $property->getString();
     }
-    return implode(', ', array_filter($strings, 'strlen'));
+    // Remove any empty strings resulting from empty items.
+    return implode(', ', array_filter($strings, 'drupal_strlen'));
   }
 
   /**