From 2c67ba8f1a99336c52e1fc1e9b713471055cf508 Mon Sep 17 00:00:00 2001
From: Alexander Reelsen <alexander@reelsen.net>
Date: Thu, 30 Jan 2014 10:39:18 +0100
Subject: [PATCH] REST Get Field Mapping API: Fix NPE if field not existent

When fixing #4738, a small issue leaked into the implementation.
The equals check in the RestAction only applied when the master node
returned the rest request, otherwise the object equality would not hold
due to being transferred over the wire and being deserialized into
another object (from and an equality point of view) than the
FieldMappingMetaData.NULL object - this could result in serialization
exceptions as an empty length bytes reference is used in toXContent.
---
 .../admin/indices/mapping/get/GetFieldMappingsResponse.java   | 4 ++++
 .../admin/indices/mapping/get/RestGetFieldMappingAction.java  | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java b/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
index 470ed6c4e247d..bd55901b9df05 100644
--- a/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
+++ b/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
@@ -108,6 +108,10 @@ public Map<String, Object> sourceAsMap() {
             return XContentHelper.convertToMap(source.array(), source.arrayOffset(), source.length(), true).v2();
         }
 
+        public boolean isNull() {
+            return NULL.fullName().equals(fullName) && NULL.source.length() == source.length();
+        }
+
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.field("full_name", fullName);
diff --git a/src/main/java/org/elasticsearch/rest/action/admin/indices/mapping/get/RestGetFieldMappingAction.java b/src/main/java/org/elasticsearch/rest/action/admin/indices/mapping/get/RestGetFieldMappingAction.java
index 43969c690a8e5..4ac48c0b855f3 100644
--- a/src/main/java/org/elasticsearch/rest/action/admin/indices/mapping/get/RestGetFieldMappingAction.java
+++ b/src/main/java/org/elasticsearch/rest/action/admin/indices/mapping/get/RestGetFieldMappingAction.java
@@ -119,7 +119,7 @@ private boolean isFieldMappingMissingField(ImmutableMap<String, ImmutableMap<Str
         for (ImmutableMap<String, ImmutableMap<String, FieldMappingMetaData>> value : mappingsByIndex.values()) {
             for (ImmutableMap<String, FieldMappingMetaData> fieldValue : value.values()) {
                 for (Map.Entry<String, FieldMappingMetaData> fieldMappingMetaDataEntry : fieldValue.entrySet()) {
-                    if (fieldMappingMetaDataEntry.getValue() == FieldMappingMetaData.NULL) {
+                    if (fieldMappingMetaDataEntry.getValue().isNull()) {
                         return true;
                     }
                 }