Fix buildMimeIds() when the ID is 0

diff --git a/framework/Mime/lib/Horde/Mime/Part.php b/framework/Mime/lib/Horde/Mime/Part.php
index 830cfd6..a385020 100644 (file)
--- a/framework/Mime/lib/Horde/Mime/Part.php
+++ b/framework/Mime/lib/Horde/Mime/Part.php
@@ -1331,7 +1331,9 @@ class Horde_Mime_Part
             }
         } else {
             $this->setMimeId($id);
-            $id .= '.';
+            $id = $id
+                ? $id . '.'
+                : '';
 
             if ($this->getType() == 'message/rfc822') {
                 if (count($this->_parts)) {