Mapping: Allow to update/merge the dynamic flag

Allow to update / merge in the dynamic flag on object or the root object mapper, meaning that it can be changed dynamically using the update mapping API.
closes elastic#3384

src/main/java/org/elasticsearch/index/mapper/object/ObjectMapper.java

@@ -61,7 +61,7 @@ public class ObjectMapper implements Mapper, AllFieldMapper.IncludeInAll {
     public static class Defaults {
         public static final boolean ENABLED = true;
         public static final Nested NESTED = Nested.NO;
-        public static final Dynamic DYNAMIC = null; // not set, inherited from father
+        public static final Dynamic DYNAMIC = null; // not set, inherited from root
         public static final ContentPath.Type PATH_TYPE = ContentPath.Type.FULL;
     }
 
@@ -286,7 +286,7 @@ protected void processField(Builder builder, String fieldName, Object fieldNode)
 
     private final Filter nestedTypeFilter;
 
-    private final Dynamic dynamic;
+    private volatile Dynamic dynamic;
 
     private final ContentPath.Type pathType;
 
@@ -389,7 +389,7 @@ public String nestedTypePathAsString() {
     }
 
     public final Dynamic dynamic() {
-        return this.dynamic;
+        return this.dynamic == null ? Dynamic.TRUE : this.dynamic;
     }
 
     protected boolean allowValue() {
@@ -800,6 +800,12 @@ public void merge(final Mapper mergeWith, final MergeContext mergeContext) throw
             }
         }
 
+        if (!mergeContext.mergeFlags().simulate()) {
+            if (mergeWithObject.dynamic != null) {
+                this.dynamic = mergeWithObject.dynamic;
+            }
+        }
+
         doMerge(mergeWithObject, mergeContext);
 
         List<Mapper> mappersToTraverse = new ArrayList<Mapper>();
@@ -866,16 +872,8 @@ public void toXContent(XContentBuilder builder, Params params, ToXContent custom
         } else if (mappers.isEmpty()) { // only write the object content type if there are no properties, otherwise, it is automatically detected
             builder.field("type", CONTENT_TYPE);
         }
-        // grr, ugly! on root, dynamic defaults to TRUE, on children, it defaults to null to
-        // inherit the root behavior
-        if (this instanceof RootObjectMapper) {
-            if (dynamic != Dynamic.TRUE) {
-                builder.field("dynamic", dynamic.name().toLowerCase(Locale.ROOT));
-            }
-        } else {
-            if (dynamic != Defaults.DYNAMIC) {
-                builder.field("dynamic", dynamic.name().toLowerCase(Locale.ROOT));
-            }
+        if (dynamic != null) {
+            builder.field("dynamic", dynamic.name().toLowerCase(Locale.ROOT));
         }
         if (enabled != Defaults.ENABLED) {
             builder.field("enabled", enabled);

src/main/java/org/elasticsearch/index/mapper/object/RootObjectMapper.java

@@ -109,10 +109,6 @@ protected ObjectMapper createMapper(String name, String fullPath, boolean enable
             } else {
                 dates = dynamicDateTimeFormatters.toArray(new FormatDateTimeFormatter[dynamicDateTimeFormatters.size()]);
             }
-            // root dynamic must not be null, since its the default
-            if (dynamic == null) {
-                dynamic = Dynamic.TRUE;
-            }
             return new RootObjectMapper(name, enabled, dynamic, pathType, mappers,
                     dates,
                     dynamicTemplates.toArray(new DynamicTemplate[dynamicTemplates.size()]),

src/test/java/org/elasticsearch/test/unit/index/mapper/merge/TestMergeMapperTests.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.index.analysis.NamedAnalyzer;
 import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.mapper.object.ObjectMapper;
 import org.elasticsearch.test.unit.index.mapper.MapperTestUtils;
 import org.junit.Test;
 
@@ -62,6 +63,20 @@ public void test1Merge() throws Exception {
         assertThat(stage1.mappers().smartName("obj1.prop1"), notNullValue());
     }
 
+    @Test
+    public void testMergeObjectDynamic() throws Exception {
+        String objectMapping = XContentFactory.jsonBuilder().startObject().startObject("type1").endObject().endObject().string();
+        DocumentMapper mapper = MapperTestUtils.newParser().parse(objectMapping);
+        assertThat(mapper.root().dynamic(), equalTo(ObjectMapper.Dynamic.TRUE));
+
+        String withDynamicMapping = XContentFactory.jsonBuilder().startObject().startObject("type1").field("dynamic", "false").endObject().endObject().string();
+        DocumentMapper withDynamicMapper = MapperTestUtils.newParser().parse(withDynamicMapping);
+        assertThat(withDynamicMapper.root().dynamic(), equalTo(ObjectMapper.Dynamic.FALSE));
+
+        DocumentMapper.MergeResult mergeResult = mapper.merge(withDynamicMapper, mergeFlags().simulate(false));
+        assertThat(mergeResult.hasConflicts(), equalTo(false));
+        assertThat(mapper.root().dynamic(), equalTo(ObjectMapper.Dynamic.FALSE));
+    }
 
     @Test
     public void testMergeObjectAndNested() throws Exception {