ES patch ordered fielddata settings

--- a/src/main/java/org/elasticsearch/index/mapper/core/AbstractFieldMapper.java
+++ b/src/main/java/org/elasticsearch/index/mapper/core/AbstractFieldMapper.java
@@ -24,7 +24,6 @@ import com.carrotsearch.hppc.cursors.ObjectCursor;
 import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import com.google.common.base.Objects;
 import com.google.common.collect.ImmutableList;
-
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
@@ -763,10 +762,17 @@ public abstract class AbstractFieldMapper<T> implements FieldMapper<T> {
             builder.field("similarity", SimilarityLookupService.DEFAULT_SIMILARITY);
         }
 
+        TreeMap<String, Object> orderedFielddataSettings = new TreeMap<String, Object>(new Comparator<String>() {
+            public int compare(String o1, String o2) {
+                return o1.toLowerCase().compareTo(o2.toLowerCase());
+            }
+        });
         if (customFieldDataSettings != null) {
-            builder.field("fielddata", (Map) customFieldDataSettings.getAsMap());
+            orderedFielddataSettings.putAll(customFieldDataSettings.getAsMap());
+            builder.field("fielddata", orderedFielddataSettings);
         } else if (includeDefaults) {
-            builder.field("fielddata", (Map) fieldDataType.getSettings().getAsMap());
+            orderedFielddataSettings.putAll((Map) fieldDataType.getSettings().getAsMap());
+            builder.field("fielddata", orderedFielddataSettings);
         }
         multiFields.toXContent(builder, params);
 
diff --git a/src/test/java/org/elasticsearch/index/mapper/multifield/MultiFieldTests.java b/src/test/java/org/elasticsearch/index/mapper/multifield/MultiFieldTests.java
index 7f4366d..5dc32d3 100644
--- a/src/test/java/org/elasticsearch/index/mapper/multifield/MultiFieldTests.java
+++ b/src/test/java/org/elasticsearch/index/mapper/multifield/MultiFieldTests.java
@@ -445,4 +445,37 @@ public class MultiFieldTests extends ElasticsearchSingleNodeTest {
             assertThat(field, equalTo(multiFieldNames[i++]));
         }
     }
+    
+    @Test
+    @SuppressWarnings("unchecked")
+    // The fielddata settings need to be in consistent order, else unneccesary mapping sync's can be triggered
+    public void testMultiFieldsFieldDataSettingsInConsistentOrder() throws Exception {
+        final String MY_MULTI_FIELD = "multi_field"; 
+        
+        // Generate a mapping with (un-/wrong-)ordered fielddata settings
+        XContentBuilder builder = jsonBuilder().startObject().startObject("type").startObject("properties")
+            .startObject("my_field").field("type", "string").startObject("fields").startObject(MY_MULTI_FIELD)
+            .field("type", "string").startObject("fielddata").field("filter.frequency.min", 2)
+            .field("filter.frequency.max", 2).field("filter.regex.pattern", ".*").endObject().endObject()
+            .endObject().endObject().endObject().endObject().endObject();
+        
+        String mapping = builder.string();
+        DocumentMapper docMapper = createIndex("test").mapperService().documentMapperParser().parse(mapping);
+
+        // Extract the fielddata settings of our field from the mapping 
+        Map<String, Object> sourceAsMap = XContentHelper.convertToMap(docMapper.mappingSource().compressed(), true).v2();
+        Map<String, Object> fieldDataSettings = (Map<String, Object>)
+            XContentMapValues.extractValue("type.properties.my_field.fields." + MY_MULTI_FIELD + ".fielddata", sourceAsMap);
+
+        // Extract/sort the keys of field data settings
+        String[] expectedKeys = fieldDataSettings.keySet().toArray(new String[]{});
+        Arrays.sort(expectedKeys);
+
+        // The keySet of fieldDataSettings is in order of data that was in the XContent object,
+        // so we expect the keySet to be ordered just as our sorted array
+        int i = 0;
+        for (String key : fieldDataSettings.keySet()) {
+            assertThat(key, equalTo(expectedKeys[i++]));
+        }
+    }
 }