diff --git a/server/src/main/java/org/elasticsearch/index/mapper/ContentPath.java b/server/src/main/java/org/elasticsearch/index/mapper/ContentPath.java
index c7fcb682053ee..f458eebe5c5de 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/ContentPath.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/ContentPath.java
@@ -58,6 +58,9 @@ public boolean isWithinLeafObject() {
     }
 
     public String pathAsText(String name) {
+        if (index == 0) {
+            return name;
+        }
         sb.setLength(0);
         for (int i = 0; i < index; i++) {
             sb.append(path[i]).append(DELIMITER);